U.S. patent application number 10/652587 was filed with the patent office on 2004-06-03 for eucalyptus biokraft pulping process.
This patent application is currently assigned to Biopulping International, Inc.. Invention is credited to Akhtar, Masood, Bajpai, Pramod K., Bajpai, Pratima.
Application Number | 20040104003 10/652587 |
Document ID | / |
Family ID | 32393778 |
Filed Date | 2004-06-03 |
United States Patent
Application |
20040104003 |
Kind Code |
A1 |
Bajpai, Pratima ; et
al. |
June 3, 2004 |
Eucalyptus biokraft pulping process
Abstract
In a new process for preparing pulped wood chips for paper
making, chips from a hardwood such as eucalyptus are inoculated
with a living culture of one or more white rot fungi. The fungi
propagate throughout the body of the wood chip, selectively
attacking the lignin of the wood without harming the cellulosic
fibers. Subsequent kraft pulping with standard chemicals results in
less chemical usage, reduced utilization of energy, improved
strength, and reduced cooking time.
Inventors: |
Bajpai, Pratima; (Patiala,
IN) ; Bajpai, Pramod K.; (Patiala, IN) ;
Akhtar, Masood; (Madison, WI) |
Correspondence
Address: |
MICHAEL BEST & FRIEDRICH, LLP
ONE SOUTH PINCKNEY STREET
P O BOX 1806
MADISON
WI
53701
|
Assignee: |
Biopulping International,
Inc.
Madison
WI
Thapar Centre for Industrial Research & Development
Patiala
|
Family ID: |
32393778 |
Appl. No.: |
10/652587 |
Filed: |
August 29, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10652587 |
Aug 29, 2003 |
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09646256 |
Nov 28, 2000 |
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6613192 |
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09646256 |
Nov 28, 2000 |
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PCT/US98/05101 |
Mar 13, 1998 |
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Current U.S.
Class: |
162/72 ; 162/91;
435/277; 435/278 |
Current CPC
Class: |
D21C 1/00 20130101; D21C
5/005 20130101; D21C 3/02 20130101 |
Class at
Publication: |
162/072 ;
162/091; 435/277; 435/278 |
International
Class: |
D21H 025/02; D21H
011/20 |
Claims
We claim:
1. A method for producing paper pulp for use in the making of paper
from eucalyptus wood chips, comprising in the steps of: a)
inoculating the wood chips with white rot fungi; b) fermenting the
wood chips so as to cause a propagation of the fungus through the
wood chips and allow the fungus to modify lignin; and c) pulping
the degraded wood chips by a known kraft process.
2. A method as claimed in claim 1 together with the further step of
bleaching the kraft pulp by a known multistage bleaching
process.
3. Canceled.
4. A method as claimed in claim 1 wherein the fermentation step is
a static fermentation step.
5. A method as claimed in claim 1 wherein the white rot fungus is
C. subvermispora.
6. A method as claimed in claim 5 wherein the C. subvermispora is a
strain selected from the group consisting of: L-14807-SS-3, CZ-3,
FP-105752-SS-5, FP-10572 and L-9186-SP.
7. A method as claimed in claim 1 wherein said white rot fungus is
Hyphodontia setulosa.
8. A method as claimed in claim 1 wherein said white rot fungus is
Phlebia subserialis.
9. A method as claimed in claim 1 wherein said white rot fungus is
Phlebia brevispora.
10. A method as claimed in claim 1 wherein said white rot fungus is
Phlebia tremellosa.
11. A method claimed in claim 1 wherein said white rot fungus is
Phanerochaete chrysosporium.
12. A method as claimed in claim 1 wherein the wood chips are
inoculated with the fungus and without nutrients.
13. A method as claimed in claim 1 wherein the wood chips are
inoculated with the fungus and known nutrients.
14. A method as claimed in claim 1 wherein the moisture content of
the chips prior to the step of inoculation is kept at fibre
saturation point or greater.
15. A method as claimed in claim 1 wherein said moisture content is
50-55% of the total wood based on a wet weight of the chips.
16. A method as claimed in claim 1 wherein the wood chips are
inoculated with 1 to 5 gms inoculum/ton of wood.
17. A method as claimed in claim 1 wherein the moisture content in
the wood during the step of fermentation is 55-65%.
18. Biotreated eucalyptus wood chips for kraft pulping prepared by
the process comprising inoculating the eucalyptus wood chips with
white rot fungi, and fermenting the wood chips so as to cause
propagation of the fungus through the wood chips and obtain
chemically modified lignin.
19. A method as claimed in claim 1, further comprising making paper
from pulp produced in step (c).
Description
FIELD OF THE INVENTION
[0001] This invention relates to a method for producing paper pulp
for use in the making of paper.
BACKGROUND OF THE INVENTION
[0002] In the manufacture of paper from wood, the wood is first
converted to pulp. Pulping involves treating wood to separate the
cellulose fibers. Pulping processes are divided into two broad
classes: chemical pulping and mechanical pulping. Chemical pulping
involves the use of chemicals to solubilize the lignin in the wood
cell wall and to release cellulose fibers. Lignin is a natural
glue-like material that holds the wood cell wall together. Chemical
pulping is a low yield process (about 50%) with significant waste
treatment and chemical recycling costs; however, the pulp produced
has extremely high strength properties. Mechanical pulping involves
the use of mechanical force to separate cellulose fibers.
Mechanical processes are high yield (up to 95%) but give paper with
lower strength properties, high color reversion and low brightness.
Thus, currently available pulping processes offer a spectrum of
pulp properties ranging from high yield, low strength mechanical
pulps to low yield, high strength chemical pulp. A mixture of
chemical pulp and mechanical pulp is used in many paper production
processes to exploit these differences.
[0003] It has been suggested that biological systems can be also
used to assist in the pulping of the wood. Attempts to improve
primary pulp production processes by using isolated ligninolytic
enzymes have so far been inhibited by the complex chemistry of the
ligninolytic enzyme system, low yields in enzyme production and the
ultrastructure of wood itself. White rot fungi, however, have great
potential for this application. These fungi not only produce the
whole set of enzymes necessary for lignin degradation but also act
as a transport system for these enzymes by bringing them into the
depth of wood chips and create the physiological conditions
necessary for enzymatic reactions. Some of the white rot fungi are
relatively selective for lignin and in that way their action mimic
that of chemical pulping agents. It is these selective lignin
degrading fungi which are useful for biopulping.
[0004] The use of white rot fungi for the biological
delignification of wood was first studied at the West Virginia Pulp
and Paper Company (now Westvaco) in the 1950s (Lawson and Still,
1957). In the 1970s Eriksson and coworkers at STFI demonstrated
that fungal treatment could result in significant energy savings
for mechanical pulping (U.S. Pat. No. 3,962,033, 1976; Ander and
Eriksson, 1975; Eriksson and Vallander, 1982). Two sequential
biopulping consortia comprised of the USDA Forest Products
Laboratory (FPL), the Universities of Wisconsin and Minnesota, and
22 pulp and paper and allied companies have established the
techno-economic feasibility of biopulping in connection with
mechanical refining (Akhtar et al., 1992a,b, 1993, Blanchette et
al., 1984, 1988, Leatham et al., 1989, 1990a,b, 1990, Myers et al.,
1988). Four U.S. patents have been granted to the Wisconsin Alumni
Research Foundation (WARF) (U.S. Pat. Nos. 5,055,159, 1991;
5,460,697, 1994; PCT Int. Appl. WO9605362 A 1 February 1996, U.S.
patent Ser. No. 08/801,704, File No. 960296.94339).
[0005] The effect of fungal pretreatment on chemical pulp
production has been investigated to a much lesser extent. On
biosulfite pulping, some work has been done in Austria and at FPL,
U.S.A. However, detailed studies have not been carried out. Messner
et al. (1992) reported .about.30% reduction in kappa number in 2
weeks in case of birch and spruce. The brightness of the unbleached
pulp increased by 4 ISO points. However, the strength properties
deteriorated. Scott et al. (1996) reported about 48 and 21%
reduction in kappa number (residual lignin in pulp) in 2 weeks with
Ceriporiopsis subvermispora strains CZ-3 and SS-3 respectively
during calcium acid sulfite pulping. However, the effect of fungal
treatment on brightness and strength properties of the pulp were
not examined. Also, the bleaching response of the fungal-treated
pulp was not seen.
[0006] On biokraft pulping, some work has been done at FPL, U.S.A.
and other laboratories on pine, aspen and red oak. Wolfaardt et al.
(1993, 1996) reported about 18% reduction in kappa number at mill
conditions, when pine wood was treated with white rot fungi.
However, under all the tested conditions, yield and viscosity was
lower and the alkali consumption was higher. Oriaran et al. (1990)
reported that glucose supplemented aspen chips pretreated with
white rot fungi led to kappa number reduction of 3 and 9% in 20 and
30 days respectively. A marked decrease in beating time was
observed only after an incubation period of 30 days, while in the
same period the water retention value increased from 102% to 137%
and the fines also increased. However, the brightness of unbleached
pulp decreased drastically by 62%. Tensile strength increased by
21% after 30 days, while the tear index decreased. Results obtained
with red oak were similar to those obtained with aspen (Oriaran,
1991; Lobosky, 1991). A systematic literature survey has shown that
no work has been done on biokraft pulping of eucalyptus. To the
best of our knowledge, this is the first report where positive
results on biokraft pulping have been obtained.
[0007] The present invention deals with a method for biokraft
pulping of eucalyptus. It involves partial degradation/modification
of eucalyptus wood with white rot fungi followed by kraft pulping
of the treated wood. It has been found that pretreatment with white
rot fungi improves chemical pulping efficiency and pulp properties
(brightness and strength). Treated wood chips could be pulped in a
shorter cooking time or could alternatively be used to produce pulp
using lower active alkali charge or sulfidity. The bleached
biopulps are easier to refine than the reference pulp.
SUMMARY OF THE INVENTION
[0008] An object of this invention is to provide a novel method for
producing paper pulp for use in the making of paper by fungal
treatment.
[0009] Another object of this invention is to provide a method for
producing paper pulp for use in the making of paper which avoids or
reduces the nutrient requirements during fungal treatment of wood
chips.
[0010] Still another object of this invention is to provide a
method for producing paper pulp for use in the making of paper
which requires less amount of chemicals in comparison to
conventional kraft pulping and consequently reduced effluents.
[0011] It is another object of the present invention to provide a
method for producing paper pulp for use in the making of paper
having higher strength.
[0012] Yet another object of the present invention is to provide a
method for producing paper pulp for use in the making of paper and
wherein the cooking time is reduced.
[0013] Other objects and advantages of the present invention will
be more apparent from the ensuing description.
[0014] According to this invention there is provided a method for
producing pulp from eucalyptus pulp for use in the making of paper
comprising in the steps of:
[0015] a) inoculating eucalyptus wood chips with white rot
fungi;
[0016] b) incubating the wood chips so as to cause a propagation of
the fungus through the wood chips and allow the fungus to modify
lignin; and
[0017] c) pulping of the degraded wood chips by a known kraft
process;
[0018] In another embodiment, the foregoing steps are augmented by
the further step of bleaching the kraft pulp by conventional
bleaching processes. It will be further recognized that the
eucalyptus chips biotreated by the metabolic activity of the white
rot fungi during incubation are themselves a commodity of commerce
which may be utilized directly in a kraft process, or transported
to another location for kraft pulping at a time remote from the
initial big treatment step.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] The present invention deals with the biological pretreatment
of wood chips for making of chemical pulp, for manufacture of
paper. It has been particularly found that through the use of white
rot fungi and the maintenance of suitable conditions during the
treatment of wood chips by white rot fungi, it is possible to
utilize a biological treatment or pretreatment as a part of
chemical pulping (kraft) process on eucalyptus which is a major raw
material for manufacture of paper in many countries. It has been
found that the process results in shorter cooking time or chemical
savings and energy savings and also results in a paper which has a
higher strength than that made from purely kraft pulping process.
The experimental evidence presented makes it clear that the
procedure is efficacious and efficient and enables the creation of
commercial scale procedures for implementing the general process
described herein.
[0020] This process makes use of white rot fungi. The particular
species of fungus found to be useful is C. subvermispora. However,
other white rot fungi can also be used. Strains of C. subvermispora
can be maintained by conventional fungal culture techniques most
conveniently by growing on potato-dextrose-agar (PDA) slants. Stock
slants may routinely be prepared from an original culture for
routine use and may be refrigerated until used. The particular
strain of C. subvermispora utilized in the examples below,
L-14807-SS-3 was obtained from the Center for Mycology Research,
Forest Products Laboratory, Madison, Wis. It was found that the
particular fungi described herein was particularly well-suited for
biokraft pulping application (Tables 1-4). However, other white rot
fungi--Hyphodontia setulosa, Phlebia subserialis, Phlebia
brevispora, Phlebia tremellosa, Phanerochaete chrysosporium and
other strains of C. subvermispora--CZ-3, L-9186-SP, FP-105732,
FP-105752-SS5, have also been found to be suitable for the present
invention (Tables 5-13).
[0021] The process of the present invention is intended and
particularly adapted for the biopulping of eucalyptus. The wood is
converted to chips through a conventional technology. Wood chips
are heat treated, preferably with steam, to disable but not
necessarily sterilize the chips prior to inoculation with the
fungus. The moisture content in the chips is kept at fiber
saturation point or greater. A preferred moisture content would be
approximately 50-55% of the total wood based on wet weight basis of
the chips.
[0022] Fungi are preferably applied to the wood as follows. To
inoculate significant volumes of wood chips, a starter inoculum may
be prepared. PDA plates are inoculated from PDA slants and
incubated at 27.+-.1.degree. C. and 70-90% relative humidity. These
plates are used to inoculate 1 liter Erlenmeyer flasks containing
potato dextrose broth and yeast extract. The inoculated flasks are
incubated without agitation in an incubator at 27.+-.1.degree. C.
and 70-90% relative humidity for 7-10 days. The surface of the
medium is covered with the fungus in the form of mat. The fungal
mat is removed from the medium, washed with sterilized water on
sterilized buchner funnel to remove all the medium. The fungal mat
is transferred into a sterile waring blender with sterile forceps
and blended with sterile water. This suspension is used to
inoculate wood chips. Scaling up the foregoing culture steps for
preparing the fungal inoculation involves preparation of media in
commercial scale vats, and growth of fungi in commercial scale
fermenters. Using industrial scale equipment, fungal cultures in
500-1500 gallon batches are readily obtainable.
[0023] Fungal treatment of wood chips is carried in bioreactor
which may be any of a number of styles capable of handling solid
media fermentation culture. It is merely required that the
stationary or solid phase reactor have sufficient aeration so as to
ensure adequate O.sub.2 flow to the fungus and significant removal
of CO.sub.2 therefrom. In fact, it is an advantage of the process
that it can be conducted in static fermentation procedure without
the need for an exotic or moving fermenting chamber thereby
allowing the process to be used more practically on a large scale.
Simply some level of aeration, humidity and temperature control is
required. On an industrial scale, the inoculated chip mass may be
incubated in cylindrical silos or in open chip piles of 20-200
tons, under nonstick conditions, provided proper ventilation is
maintained, as discussed more fully hereafter.
[0024] For the fungal treatment, wood chips are put in the
bioreactor, autoclaved and cooled to room temperature, or exposed
to steam to disable native microorganism populations without
absolute sterilization. The wood chips to be treated are inoculated
with starter culture. The amount of inoculum added to the chips can
vary. It should be sufficient to ensure growth and spread to all
chips in the bioreactor. Inoculum level of 1 to 5 gm per ton of
wood chips was found to be sufficient. The chips so inoculated will
then be incubated during a time period in which the fungal mycelia
will penetrate throughout the wood chips. It has been found that
nutrients are not required during fungal treatment of eucalyptus
wood chips. Addition of nutrients does not give additional
biopulping benefits but result in more loss in the weight of wood
chips and unbleached pulp yield. The most desired temperature range
depends on the fungal strains.
[0025] It has been found that a bioreactor kept in the range of
27.+-.2.degree. C. with a moisture content in the wood of 55-65%
achieves a great degree of mycelia penetration of wood chips that
results in significant degradation of wood chips for paper pulping
process. The wood chips are aerated continuously during the
incubation period with the air saturated with moisture that the
wood maintains the constant moisture content of about 55-65%. It
has been found that under the conditions used experimentally, an
incubation period of 1 to 3 weeks results in significant
modification of the wood chips and reduction in cooking time or
chemicals requirement and energy savings in the subsequent chemical
(kraft) pulping process.
[0026] The biologically degraded wood chips are then subjected to
chemical pulping (kraft) process. The treated chips could be cooked
in shorter time or require less chemicals during cooking and less
energy during refining. The biokraft pulps made through this
procedure is then bleached in a multistage bleaching process and
made into paper using standard paper-making techniques. Paper made
from biokraft pulp is better in quality, strength and texture to
that created through simple kraft pulping process.
[0027] Effective biopulping can be carried out under nonsterile
conditions in which naturally occurring flora are present and
viable. However, better results are obtained with steamed or
autoclaved wood chips. Eucalyptus wood chips are exposed to live
steam resulting in elevating their surface temperature to about
90.degree. to 100.degree. C., as measured immediately after steam
treatment. The exposure time is a function of the temperature of
the superheated vapor and also the inlet pressure. While
101.degree. to 108.degree. C. influent steam at 15 to 75 in line
psi for exposure times of 3 to 50 seconds is adequate, the optimum
values are best determined in a few empirical process runs for the
particular type and configuration of equipment, as hereinafter
described in more detail.
[0028] The chamber in which steam treatment takes place should not
be too tightly packed. Open space of about under 10% to over 65% of
the volume capacity is sufficient to allow penetration of steam to
all chip surfaces provided that the chips can be mechanically
turned or agitated to prevent impeded exposure to steam at touching
surfaces. For example, in the screw conveyor used in a preferred
embodiment of the invention, the open space above the chips in the
conveyor was found to be approximately 57% to 69%. (In addition,
the void space between the chips amounted to approximately 61%.
Therefore, the total void space in the conveyor amounted to
approximately 83% (large chips) to 88% (small chips). Uniformity of
steam treatment is very important, as the naturally occurring flora
must be uniformly disabled or biosuppressed physiologically to
avoid spots of overgrowth by contaminants during the subsequent
incubation step.
[0029] A particularly efficient method of steam treatment is by
injecting steam into a continuous flow screw or auger bearing the
chips at about 30% to 45% spacial density as discussed above. It
was found that exposure time of chips adequate for the present
process could be only 40 seconds compared to 5-10 minutes in a
quiescent batch mode. Steam was released at moderate pressure and
applied ambiently without pressurizing the vessel.
[0030] A number of species of contaminating organisms can readily
be isolated from moistened wood chips including Aspergillis spp.,
Colletotrichum spp., Trichoderma spp., Gliocladium spp., Ophiostoma
spp., Penicillium spp., Ceratocystis spp. , Nectria spp., Cytospora
spp., and Alternaria spp. Many of these are more physiologically
robust and faster growing than the inoculating lignin-degrading or
modifying fungi of choice. Growth of these organisms is also
enhanced in many instances by the nutrient adjuvants contained in
the fungal inoculum. Therefore, addition of such nutrients is
avoided.
[0031] Once the indigenous, undesirable microbes are disabled or
suppressed by steam treatment, the less robust and more fastidious
white-rot fungi in the inoculum are able to remain dominant over
extended periods. The disabled organisms are still viable and
capable of becoming dominant, as shown by biopulping runs in which
the treatment temperature was inadvertently allowed to rise only to
suboptimal levels. In those instances the runs were ruined by
overgrowth of the contaminating fungi. Clearly a highly delicate
but controllable process balance must be maintained, but it is
unclear scientifically what competitive factors are at work to
maintain the desired biological balance over extended incubations.
Reducing exposure to steam to a minimum without sterilization also
has favorable implications for process costs. The low exposure time
conductive to a continuous treatment means that high volume
treatment required in any commercial scale process is attainable in
the present invention.
[0032] In the next step of the process, the chips must be cooled
sufficiently to permit inoculation of the biopulping fungi without
killing or disabling them. Many of the useful species may actually
be more sensitive to elevated temperatures than their naturally
occurring flora counterparts. Chips steam treated on a continuously
moving path are passed through heat transfer means which cool the
chips to an appropriate temperature for inoculation. Applicants
have found that the most cost effective and simplest method is to
place an in-line air blower manifold directly in the conveyance
path, and adjust the air flow to a rate that will cool the passing
chips adequately.
[0033] It has been determined empirically that chips cooled to
about 40.degree.-45.degree. C. and as high as 50.degree. C. are
cool enough not to heat shock the fungi contained in the inoculum.
The highest temperature tolerated by biopulping organisms may vary
from species to species, so that some empirical tests may be
necessary to determine a physiologically suitable temperature for
inoculation of that species. Cooling only to the highest
physiologically suitable temperature minimizes the cooling time and
speeds the process, and reduces the energy consumed.
[0034] Inoculation of the biopulping fungi is preferably carried
out in-line, and applied as a liquid spray to the passing wood
chips. As in the steam treatment, the working action of agitated
conveyor or auger allows inoculum to be uniformly adsorbed onto the
chip surfaces by tumbling and churning during rotary or other
agitated conveyance. It is important that the inoculum be applied
substantially thoroughly and uniformly to the chip surfaces. If the
biopulping fungi are to maintain dominance over other flora, the
contaminating flora should not be given a sufficient opportunity to
reestablish themselves in local areas of the chip surfaces where
coverage of inoculum is uneven.
[0035] The enzymatic breakdown or modification of lignin by fungi
is an exothermic reaction, so that when a large mass of chips is
undergoing delignification, a substantial concentration of heat
ensues. As the surface area of the mass of chips diminishes
relative to the total mass, the problem intensifies since wood
itself is an excellent heat insulator. The most practical way to
dissipate heat in the chips to prevent the temperature from
exceeding the level at which the biopulping fungi are killed, and
the contaminants begin to overgrow the fungi, is by forcing air
through the chips.
[0036] It has been found that the temperature of chip piles can be
adequately controlled and maintained at levels biocompatible with
the continued propagation and dominance of the fungus by loading
the chips onto an air pervious frame defining a plurality of ducts
through which forced air is passed. It has been empirically
determined that the humidity of the air should be in a range from
at least 30% up to over 95% relative humidity, preferably about
85%, and the flow rate should be adjusted seasonally to maintain
the temperature in the core of the pile within the active growth
range of the fungus, which must be determined for each species. In
the case of C. subvermispora, the range is approximately 27.degree.
to 32.degree. C.
[0037] After inoculation, the chips may be conveniently collected
in large piles. Temperature and humidity control are important for
optimal fungal propagation and lignin degradation or modification.
It has been determined that practical control can be maintained for
piles loaded onto the bottom frame referred to above having
dimensions about 40-55 feet high, 100 feet wide and any length. Two
400 foot long piles can accommodate a pulp plant utilizing 600 tons
of chips daily. To obtain proper humidity, wet bulb/dry bulb tests
can be performed on the influent air. Relative humidity should
preferably be maintained at about 70%-90%. Humidification of air by
conventional means such as fogging prior to pumping or fanning into
the frame ducts is generally necessary. The amount of heat
generated in the pile generally requires continuous dissipation by
forced air flow even during the winter months in the northern
climes.
[0038] Incubation times are related to the degree of lignin
digestion or modification desired, the type of wood chips being
handled, and the particular fungus or combination of fungi being
utilized in the process. Useful periods of incubation range from a
few days to four weeks. On the other hand, prolonged incubation
results in larger standing inventories of chips and larger on site
storage capacity.
[0039] Tubular reactors (silo reactors) can also be used for
biopulping. This silo reactor has a large-scale (multiton)
capacity. A perforated plate at the bottom of the reactor supports
the chips approximately 5 cm above the bottom of the reactor. Air
is supplied to this void space at the bottom center of the reactor.
A baffle plate immediately above the air inlet distributes the air
more evenly across the bottom of the reactor.
[0040] Approximately 160 kg of chips (dry basis) were
decontaminated by steaming, as noted above. After cooling
(typically overnight), the chips were inoculated using a protocol
involving mixing of the inoculum in a large rotating "V" mixer or
by auger. The inoculated chips are then transferred to the silo
reactor via auger. The chips are ventilated with nearly saturated
moist air with the velocity adjusted to maintain the proper
temperature range throughout the reactor.
[0041] The details of the process of the present invention will
become more apparent from the following examples which describe the
laboratory-scale utilization of the present process and the results
achieved thereby.
EXAMPLES
[0042] 1. Biokraft Pulping of Eucalyptus with C. subvermispora at
the Same Active Alkali Charge.
[0043] In this example, C. subvermispora L-14807-SS-3 culture which
was maintained on PDA slant was used. Working culture was prepared
from the stock culture for routine use. For inoculum preparation,
PDA plate cultures were inoculated from the working stock culture.
The plate cultures were incubated at 27.+-.1.degree. C. at 70-90%
relative humidity for 7-10 days. These plates were used to
inoculate 1 liter Erlenmeyer flasks containing 100 ml of liquid
medium which contained 36 g of potato dextrose broth and 10.91 g of
yeast extract in 1500 ml water. The inoculated flasks were
incubated without agitation in an incubator at 27.+-.1.degree. C.
and 70-90% relative humidity for 10 days. The surface of the medium
was covered with the fungus in the form of mat. The fungal mat was
removed from the medium, washed with sterilized water to remove all
the medium. The fungal mat was transferred into a sterile waring
blender with sterile forceps. About 50 ml of sterile water was
added to the blender and the mycelium was blended for 15 seconds.
The fungal suspension was transferred to a beaker and diluted to
100 ml by adding sterile water. This suspension was used to
inoculate wood chips. 1500 gm (o.d. basis) of eucalyptus wood chips
were put in aerated static bed bioreactor and autoclaved at
121.degree. C. for 60 min. and cooled to room temperature. About
7.5 mg (dry wt.) of the fungus (5 g dry wt. of the fungus per ton
of material) was added to 1500 gm of wood chips in the bioreactor
and mixed thoroughly. The moisture content of chips was adjusted to
50-55%. The bioreactor was incubated in a room temperature varying
between 27-32.degree. C. The bioreactor was aerated with humidified
air at a rate of 1 cubic ft. per hour. After incubation for 2
weeks, the fungal-treated wood chips were removed from the
bioreactor and subjected to kraft pulping in bomb digesters. The
conditions for the kraft cooks were 17% active alkali (AA) as
Na.sub.2O, 22.9% sulfidity, 3.0 liquor/wood ratio, 165.degree. C.
cooking temperature, 90 minutes to cooking temperature and 90
minutes at cooking temperature. The biokraft pulp was bleached in a
multistage bleaching process (CEHD) sequence and made into
paper.
[0044] The fungus was found to grow very well on eucalyptus chips
in the bioreactor. The fungal-treated chips appeared brighter than
the control chips. The weight loss of wood chips after the fungal
treatment was about 2.4%. When the cooking was done at the same
active alkali charge for reference chips as well as fungal-treated
chips, the brightness and strength properties of unbleached biopulp
were higher as compared to those of control. However, the
unbleached yield of the biopulp was lower and there was no drop in
the permanganate number (P.No.) of the biopulp. The unbleached
brightness of biopulp was higher by more than 2 points. Tensile
index and breaking length of biopulp increased by 13.8%, burst
index increased by 35.7% and double fold increased by 66.6%. The
unbleached yield of the biopulp decreased slightly. The bleaching
response of biopulp was better than that of control. The final
brightness of biopulp (CEHD sequence) was higher by 2 points. The
bleached biopulp was easier to refine than the reference pulp. The
beating time was reduced by 33%. The strength properties of
bleached biopulp were better than those of control (Table 1).
[0045] 2. Biokraft Pulping of Eucalyptus with C. subvermispora at
Reduced Active Alkali Charge.
[0046] In this example, fungal-treated chips (Inoculum level 5 g/T
wood) were cooked at 14% AA charge. Even then, the unbleached
brightness of biopulp was better than that of the reference pulp
(no fungal treatment) obtained by cooking the chips at 17% AA
charge. The strength properties of biopulp (with 14% AA charge)
were substantially higher and the bleaching response was better
than those of reference pulps (with 17% AA charge). When the
bleaching was done under identical conditions at the same total
chemical charge, the final brightness of these biopulps was higher
by about 1 point in a 4-stage (CEHD) bleaching sequence. The
bleached biopulps were easier to refine than the reference pulp.
The beating time was reduced by .about.20%. Most of the strength
properties of the bleached biopulps were better than those of
control (Table 2).
[0047] 3. Biokraft Pulping of Eucalyptus with C. subvermispora at
Reduced Cooking Time.
[0048] In this example, fungal-treated wood chips (Inoculum level,
5 g/T wood) were cooked for shorter time as compared to reference
chips. Cooking time was reduced by 16.6, 25.0 and 33.3%. The time
to cooking temperature was fixed at 90 minutes and time at cooking
temperature was reduced. When the cooking time was reduced by 25%
and 33.3%, the control wood chips after cooking remain partially
uncooked. On the other hand, the fungal-treated chips were still
uniformly cooked even with 30 minutes cooking. In all the cases,
the brightness and mechanical properties of unbleached biopulps
were higher and the bleaching response was better as compared to
control (untreated chips cooked for 90 minutes at 165.degree. C).
The final brightness of the biopulps in CEHD sequence was also
higher as compared to control. When the cooking time was reduced by
16.6 and 25%, higher final pulp brightness was obtained at the same
total chemical charge. The bleached biopulps were easier to refine
than the reference pulp. The beating time was reduced by 16-18%.
There was no significant difference in the strength properties of
bleached biopulps and reference pulp (Table 3).
[0049] 4. Biokraft Pulsing of Eucalyptus with C. subvermispora at
Reduced Sulfidity.
[0050] In this example, fungal-treated chips (Inoculum level, 5 g/T
wood) were cooked at reduced sulfidity. The sulfidity was reduced
from 22.9% to 16%. The unbleached brightness and strength
properties of the fungal-treated chips at 16% sulfidity level were
found to be higher than those of reference chips cooked at 22.9%
sulfidity (Table 4).
[0051] References Cited
[0052] Akhtar, M., Attridge, M. C. and Myers, G. C. (1992a) Tappi
J., 75(2), 105-109.
[0053] Akhtar, M., Attridge, M. C., and Blanchette, R. A. (1992b)
In: Biotechnology in the pulp and paper industry (Kuwahara, M. and
Shimada, M. eds.) Tokyo, UNI Publishers Company Ltd., p. 545.
[0054] Akhtar, M., Attridge, M. C., Myers, G. C. and Blanchette, R.
A. (1993) Holzforschung, 47(1), 36-40.
[0055] Ander, P. and Eriksson, K. E. (1975) Svensk Papperstidning,
18, 641.
[0056] Bar-lev, S. S., Kirk, T. K. and Chang, H. M. (1982) Tappi
J., 65(10), 111-113.
[0057] Blanchette, R. A. (1984) Applied & Environmental
Microbiology, 48(3), 647-653.
[0058] Blanchette, R. A. and Burnes, T. A. (1988) Biomass, 15,
93-101.
[0059] Eriksson, K. E. and Vallander, L. (1982) Svensk
Paperstidning, 85(6), R33-R38.
[0060] Eriksson, K. E., Ander, P., Henningsson, M. and Nilsson, T.,
U.S. Pat. No. 3,962,033, June 1976.
[0061] Labosky Jr., P., Zhang, J. and Royse, D. J. (1991) Wood
Fiber Sci., 23, 533-542.
[0062] Lawson, L. R. and Still, C. N. (1957) Tappi J., 40,
56A-80A.
[0063] Leatham, G. F. et al., Presented at Biotechnology in the
Pulp and Paper Industry, 4th International Conference, Raleigh, N.
C., May 16-19, 1989.
[0064] Leatham, G. F., Myers, G. C., Wegner, T. H. and Blanchette,
R. A. (1990a) Tappi J., 73(3), 249-255.
[0065] Leatham, G. F., Myers, G. C., Wegner, T. H. and Blanchette,
R. A. (1990b) Tappi J., 73(5), 197-200.
[0066] Messner, K., Masek, S., Srebotnik, E. and Techt, G. (1992)
In: Biotechnology in the Pulp and Paper Industry, Proceedings of
the 5th International Conference on Biotechnology in the Pulp and
Paper Industry (Kuwahara, M. and Shimada, M., Eds.) pp. 9-13, Uni
Publishers Co. Ltd., Tokyo.
[0067] Myers, G. C., Leatham, G. F., Wegner, T. H. and Blanchette,
R. A. (1988) Tappi J., 71(5), 105-108.
[0068] Oriaran, T. Ph., Labosky Jr., P. and Blankenhorn, P. R.
(1990) Tappi J., 73(7), 147-152.
[0069] Oriaran, T. Ph., Labosky Jr., P. and Blankenhorn, P. R.
(1991) Wood Fiber Sci., 23, 316-327.
[0070] Scott, G. M., Akhtar, M., Lentz, M., Sykes, M. and Abubakr,
S. (1996) Biotechnology in the Pulp and Paper Industry: Recent
Advances in Applied and Fundamental Research (Srebotnik, E.,
Messner, K. Ed.), Facultas-Universitats Verlag, Bergasse 5, A-1090
Wien, Austria, p. 217-219.
[0071] Wolfaardt, J. F., Boshoff, I. E., Bosman, J. L., Rabie, C.
J. and van der Esthuizen, G. C. A. (1993) In: FEMS Symposium,
Lignin Biodegradation and Transformation, Book of Proceedings
(Duarte, J. C., Ferreira, M. C. and Ander, P., Eds.) pp. 67-69,
Forbitec Editions, Lisboa.
[0072] Wolfaardt, J. F., Bosman, J. L., Jacobs, A., Male, J. R. and
Rabie, C. J. (1996) Biotechnology in the Pulp and Paper Industry:
Recent Advances in Applied and Fundamental Research (Srebotnik, E.,
Messner, K. Ed.), Facultas-Universitats Verlag, Bergasse 5, A-1090
Wien, Austria, p. 211-216.
1TABLE 1 Biokraft pulping of eucalyptus with C. subvermispora
L-14807-SS-3 at same active alkali charge.sup.1 a. Pulp properties
Parameter Treated.sup.2 Control P.No. 14.46 14.40 Unbleached
brightness 29.1 27.0 (% PV) Unbleached pulp yield 45.8 46.1 (%)
Final brightness 87.2 85.2 (% PV) Bleach chemical consumption
(kg/TP) Elemental Cl.sub.2 40.0 40.0 NaOH 18.8 18.8 Hypo 12.3 12.3
Chlorine dioxide 6.0 6.0 b. Strength properties Unbleached Bleached
Parameter Control Treated Control Treated Wetness (.degree. SR) 17
18 35 35 Beating time -- -- 30 20 (min) Tensile index 42.15 47.98
75.51 82.30 (N m/g) Breaking 4299 4894 7702 8394 length (m) Burst
index 1.93 2.62 4.59 5.14 (kN/g) Tear index (mNm.sup.2/g) 5.66 5.48
6.92 7.20 Double fold 6 10 102 112 (No.) .sup.1Kraft cooking of
fungal-treated chips and reference chips (no fungal treatment)
conducted at 17% AA charge .sup.2Fungal treatment for 2 weeks;
Inoculum level, 5 g/T wood
[0073]
2TABLE 2 Biokraft pulping of eucalyptus with C. subvermispora at
reduced active alkali charge a. Pulp properties. AA charge (%) 17
14 14 14 Parameter Control Treated Control Treated P. No. 13.50
15.86 16.28 15.86 Unbleached brightness 27.3 28.3 25.9 28.3 (% PV)
Unbleached pulp yield 45.67 45.53 47.15 45.53 (%) Final brightness
87.0 88.3 87.6 89.1 (% PV) Bleach chemical consumption (kg/TP)
Elemental Cl.sub.2 37.5 37.5 46.1 46.1 NaOH 19.1 19.1 18.9 18.9
Hypo 13.5 13.5 12.8 12.8 Chlorine dioxide 6.0 6.0 6.0 6.0 Treatment
of eucalyptus with C. subvermispora L-14807-SS-3 for 2 weeks,
Inoculum level, 5 g/T wood Cooking of fungal-treated chips
conducted at 14% AA charge; cooking of reference chips conducted at
17% and 14% AA charge b. Strength properties Unbleached Bleached
Control Treated Control Treated Parameter 17% AA 14% AA 14% AA 17%
AA 14% AA Wetness 16.5 17.0 17.5 35.0 35.0 (.degree.SR) Beating
time -- -- -- 29.0 22.5 (min) Tensile 33.68 34.1 40.75 66.25 72.26
index (N m/g) Breaking 3435 3478 4157 6757 7364 length (m) Burst
index 1.38 1.62 1.89 4.30 4.85 (kN/g) Tear index 5.45 5.77 6.81
7.68 7.88 (mN m.sup.2/g) Double fold 5 8 10 58 80 (No.)
[0074]
3TABLE 3 Effect of fungal treatment on cooking time 1) Reduction of
cooking time by 16.6% a. Pulp properties Control Treated Control
Treated Parameter 90 min. 60 min. 60 min. 60 min. P.No. 14.66 15.85
15.66 15.85 Unbleached 28.0 29.5 28.9 29.5 brightness (% PV)
Unbleached pulp 46.0 44.8 46.5 44.8 yield (%) Final brightness 88.6
90.5 89.5 90.4 (% PV) Bleach chemical consumption (kg/TP) Elemental
Cl.sub.2 40.9 40.9 44.0 44.0 NaOH 19.4 19.4 19.5 19.5 Hypo 19.2
19.2 19.6 19.6 Chlorine 5.0 5.0 5.0 5.0 dioxide b. Strength
properties Unbleached Bleached Control Treated Control Treated
Parameter 90 min. 60 min. 90 min. 60 min. Wetness (.degree. SR)
17.0 18.0 35.0 35.5 Beating time -- -- 25.0 21.0 (min) Tensile
index 32.22 36.93 63.09 64.54 (N m/g) Breaking 3286 3767 6435 6583
length (m) Burst index 1.42 1.81 4.05 4.10 (kN/g) Tear index
(mNm.sup.2/g) 5.79 6.00 7.76 7.20 Double fold 5 8 50 54 (No.) 2)
Reduction of cooking time by 25% a. Pulp properties Control Treated
Control Treated Parameter 90 min. 45 min. 45 min. 45 min. P.No.
14.66 16.50 partially 16.50 uncooked chips Unbleached brightness
28.0 30.5 30.8 (% PV) Unbleached pulp yield 45.9 44.9 44.9 (%)
Final brightness 88.6 90.1 90.5 (% PV) Bleach chemical consumption
(kg/TP) Elemental Cl.sub.2 40.9 40.9 47.7 NaOH 19.2 19.2 19.7 Hypo
19.5 19.5 21.4 Chlorine dioxide 5.0 5.0 5.0 b. Strength properties
Unbleached Bleached Control Treated Control Treated Parameter 90
min. 45 min. 90 min. 45 min. Wetness (.degree.SR) 17.0 18.0 35.0
35.0 Beating time -- -- 25.0 21.0 (min) Tensile index 32.22 39.89
63.09 67.94 (N m/g) Breaking 3286 3989 6435 6930 length (m) Burst
index 1.42 1.91 4.05 4.20 (kN/g) Tear index (mNm.sup.2/g) 5.79 5.91
7.76 7.50 Double fold 5 7 50 60 No.) +TC,1/32 3) Reduction of
cooking time by 33.3% a. Pulp properties Control Treated Control
Treated Parameter 90 min. 30 min. 30 min. 30 min. P.No. 13.81 16.59
partially 16.59 uncooked chips Unbleached brightness 27.6 30.8 30.8
(% PV) Unbleached pulp yield 46.076 46.37 46.37 (%) Final
brightness 88.6 88.71 90.5 (% PV) Bleach chemical consumption
(kg/TP) Elemental Cl.sub.2 38.4 38.4 46.2 NaOH 19.8 22.3 22.3 Hypo
16.2 16.2 16.3 Chlorine dioxide 6.0 6.0 6.0 b. Strength properties
Unbleached Bleached Control Treated Control Treated Parameter 90
min 30 min 90 min 30 min Wetness (.degree.SR) 17.0 17.5 33.5 33.5
Beating time -- -- 27.0 22.0 (min) Tensile index 39.75 43.65 68.89
70.52 (N m/g) Breaking 4055 4453 7026 7193 length (m) Burst index
1.94 2.18 4.59 4.79 (kN/g) Tear index (mNm.sup.2/g) 6.73 7.03 7.75
8.14 Double fold 7 11 58 58 (No.) Treatment of eucalyptus with C.
subvermispora L-14801-SS-3 for 2 weeks Time to cooking temperature
was fixed at 90 min and time at cooking temperature was reduced.
Treatment of eucalyptus with C. subvermispora L-14807-SS-3 for 2
weeks, Inoculum level 5 g/T wood.
[0075]
4TABLE 4 Effect of fungal treatment on sulfidity requirement in
cooking Control Treated Parameter 22.9% S 16% S 16% S 22.9% S P.No
13.71 14.16 14.16 13.82 Unbleached 28.9 28.0 30.3 31.2 brightness
(% PV) Unbleached pulp 46.2 45.6 45.4 45.1 yield (%) Wetness
(.degree.SR) 17.5 17.5 18.0 18.0 Tensile index 35.71 33.91 41.79
42.10 (N m/g) Breaking length (m) 3642 3458 4262 4293 Burst index
(kN/g) 1.55 1.32 1.81 2.01 Tear index (mNm.sup.2/g) 5.69 5.35 6.90
6.12 Double fold (No.) 5 4 8 9 Treatment of eucalyptus chips with
C. subvermispora for L-14807-SS-3 for 2 weeks, Inoculum level, 5
g/T wood. Cooking conditions: 17% AA as Na.sub.2O, 165.degree. C.,
time to cooking temp. 90 min., Time at cooking temp. 90 min.
[0076]
5TABLE 5 Biokraft pulping of eucalyptus with C. subvermispora CZ-3
at reduced active alkali charge a. Pulp properties AA Charge (%) 17
14 14 14 Parameter Control Treated Control Treated P.No. 13.54
16.41 16.04 16.41 Unbleached brightness 28.4 28.8 28.2 28.8 (% PV)
Unbleached pulp yield 46.20 45.55 47.61 45.55 (%) Final brightness
87.7 87.8 88.7 89.3 (% PV) Bleach chemical consumption (kg/TP)
Elemental Cl.sub.2 37.6 37.6 45.3 45.3 NaOH 19.2 19.2 19.0 19.0
Hypo 13.9 13.9 13.2 13.2 Chlorine dioxide 6.0 6.0 6.0 6.0 b.
Strength properties Unbleached Bleached Control Treated Control
Treated Parameter 17% AA 14% AA 14% AA 17% AA 14% AA Wetness 17.0
17.0 17.5 35.5 35.0 (.degree.SR) Beating time -- -- -- 28.5 20.5
(min) Tensile 36.02 43.63 44.65 74.64 76.34 index (N m/g) Breaking
3674 4452 4554 7614 7788 length (m) Burst index 1.54 1.85 2.40 5.06
5.22 (kN/g) Tear index 6.98 7.01 7.76 7.90 8.19 (mNm.sup.2/g)
Double fold 6 10 11 93 115 (No.) Treatment of eucalyptus with C.
subvermispora CZ-3 for 2 weeks, Inoculum level, 5 g/T wood Cooking
of fungal-treated chips conducted at 14% AA charge; cooking of
reference chips conducted at 17% and 14% AA charge
[0077]
6TABLE 6 Biokraft pulping of eucalyptus with C. subvermispora
L-9186-SP at reduced active alkali charge a. Pulp properties AA
Charge (%) 17 14 14 14 Parameter Control Treated Control Treated
P.No. 13.89 16.25 16.42 16.25 Unbleached pulp yield 46.10 46.85
47.13 46.85 (%) Unbleached brightness 27.8 28.9 27.7 28.9 (% PV)
Final brightness 88.7 89.5 89.4 90.6 (% PV) Bleach chemical
consumption (kg/TP) Elemental Cl.sub.2 38.6 38.6 46.6 46.6 NaOH
19.1 19.1 18.8 18.8 Hypo 13.4 13.4 12.3 12.3 Chlorine dioxide 6.0
6.0 6.0 6.0 b. Strength properties Unbleached Bleached Control
Treated Control Treated Parameter 17% AA 14% AA 14% AA 17% AA 14%
AA Wetness 16.0 16.0 16.5 36.5 36.5 (.degree.SR) Beating time -- --
-- 23.0 19.0 (min) Tensile 35.95 38.32 42.31 70.22 70.61 index (N
m/g) Breaking 3667 3908 4316 7163 7202 length (m) Burst index 1.67
1.78 1.93 4.48 5.21 (kN/g) Tear index 6.49 7.06 7.31 7.69 7.87
(mNm.sup.2/g) Double fold 7 8 10 65 90 (No.) Treatment of
eucalyptus with C. subvermispora L-9186-SP for 2 weeks, Inoculum
level, 5 g/T wood Cooking of fungal-treated chips conducted at 14%
AA charge; cooking of reference chips conducted at 17% and 14% AA
charge
[0078]
7TABLE 7 Biokraft pulping of eucalyptus with C. subvermispora
FP-105752 at reduced active alkali charge a. Pulp properties AA
Charge (%) 17 14 14 14 Parameter Control Treated Control Treated
P.No. 14.25 16.89 16.65 16.89 Unbleached pulp yield 45.98 46.41
47.67 46.41 (%) Unbleached brightness 28.8 28.8 28.4 28.8 (% PV)
Final brightness 88.0 89.2 89.2 90.0 (% PV) Bleach chemical
consumption (kg/TP) Elemental Cl.sub.2 39.7 39.7 47.4 47.4 NaOH
18.8 18.8 18.4 18.4 Hypo 12.3 12.3 10.9 10.9 Chlorine dioxide 6.0
6.0 6.0 6.0 b. Strength properties Unbleached Bleached Control
Treated Control Treated Parameter 17% AA 14% AA 14% AA 17% AA 14%
AA Wetness 16.5 16.5 17.0 35.0 35.0 (.degree.SR) Beating time -- --
-- 29.5 20.0 (min) Tensile 33.29 41.49 42.14 71.58 72.98 index (N
m/g) Breaking 3395 4232 4298 7301 7444 length (m) Burst index 1.70
1.98 2.01 4.90 5.25 (kN/g) Tear index 6.01 6.28 6.25 7.88 8.13
(mNm.sup.2/g) Double fold 6 8 12 88 126 (No.)
[0079]
8TABLE 8 Biokraft pulping of eucalyptus with C. subvermispora
FP-105752-SS-5 at reduced active alkali charge a. Pulp properties
AA Charge (%) 17 14 14 14 Parameter Control Treated Control Treated
P.No. 13.91 16.51 16.37 16.51 Unbleached pulp yield 46.49 46.42
47.74 46.42 (%) Unbleached brightness 28.6 29.0 28.5 29.0 (% PV)
Final brightness 86.9 87.5 87.8 88.9 (% PV) Bleach chemical
consumption (kg/TP) Elemental Cl.sub.2 38.7 38.7 46.4 46.4 NaOH
19.5 19.5 19.4 19.4 Hypo 14.9 14.9 14.6 14.6 Chlorine dioxide 6.0
6.0 6.0 6.0 b. Strength properties Unbleached Bleached Control
Treated Control Treated Parameter 17% AA 14% AA 14% AA 17% AA 14%
AA Wetness 16.5 16.0 17.0 35.0 35.5 (.degree.SR) Beating time -- --
-- 26.0 19.0 (min) Tensile 37.60 40.10 41.00 69.50 79.10 index (N
m/g) Breaking 3835 4090 4183 7089 8069 length (m) Burst index 1.64
1.84 1.96 4.88 5.34 (kN/g) Tear index 6.54 6.80 6.55 8.71 7.88
(mNm.sup.2/g) Double fold 6 7 10 82 93 (No.) Treatment of
eucalyptus with C. subvermispora FP-105752-SS-5 for 2 weeks,
Inoculum level, 5 g/T wood Cooking of fungal-treated chips
conducted at 14% AA charge; cooking of reference chips conducted at
17% and 14% AA charge
[0080]
9TABLE 9 Biokraft pulping of eucalyptus with Phlebia brevispora at
reduced active alkali charge a. Pulp properties AA charge (%) 17 14
14 14 Parameter Control Treated Control Treated P. No. 13.06 16.11
15.62 15.9 Unbleached pulp yield 45.80 45.10 46.50 45.30 (%)
Unbleached brightness 27.6 28.7 27.0 27.5 (% PV) Final brightness
87.4 88.4 88.1 89.2 (% PV) Bleach chemical consumption (kg/TP)
Elemental Cl.sub.2 36.3 36.3 43.9 43.9 NaOH 19.9 19.9 19.7 19.7
Hypo 14.7 14.7 13.8 13.8 Chlorine dioxide 6.0 6.0 6.0 6.0 Treatment
of eucalyptus with Phlebia brevispora for 2 weeks, Inoculum level,
5 g/T wood Cooking of fungal-treated chips conducted at 14% AA
charge; cooking of reference chips conducted at 17% and 14% AA
charge b. Strength properties Unbleached Bleached Control Treated
Control Treated Parameter 17% AA 14% AA 14% AA 17% AA 14% AA
Wetness 17.0 17.0 17.5 35.5 35.5 (.degree.SR) Beating time -- -- --
26.0 21.0 (min) Tensile 36.02 43.63 44.65 74.64 76.34 index (N m/g)
Breaking 3674 4452 4554 7614 7788 length (m) Burst index 1.70 1.95
2.30 4.95 5.16 (kN/g) Tear index 6.89 7.06 7.31 7.69 7.87 (mN
m.sup.2/g) Double fold 6 10 11 93 115 (No.)
[0081]
10TABLE 10 Biokraft pulping of eucalyptus with Hyphodontia setulosa
at reduced active alkali charge a. Pulp properties AA Charge (%) 17
14 14 14 Parameter Control Treated Control Treated P.No. 13.39
15.50 16.37 15.90 Unbleached brightness 27.9 29.0 27.1 29.0 (% PV)
Unbleached pulp yield 45.92 45.75 47.01 46.10 (%) Final brightness
87.5 88.9 88.6 89.9 (% PV) Bleach chemical consumption (kg/TP)
Elemental Cl.sub.2 37.2 37.2 46.4 46.4 NaOH 20.0 20.0 19.6 19.6
Hypo 16.7 16.7 12.3 12.3 Chlorine dioxide 6.0 6.0 6.0 6.0 b.
Strength properties Unbleached Bleached Control Treated Control
Treated Parameter 17% AA 14% AA 14% AA 17% AA 14% AA Wetness 17.0
17.0 17.5 35.5 35.5 (.degree.SR) Beating time -- -- -- 28.0 22.0
(min) Tensile 37.60 40.10 41.00 69.50 79.10 index (N m/g) Breaking
3835 4090 4183 7089 8069 length (m) Burst index 1.60 1.85 2.20 5.06
5.22 (kN/g) Tear index 6.90 7.01 7.69 7.90 8.06 (mNm.sup.2/g)
Double fold 6 9 11 91 110 (No.) Treatment of eucalyptus with
Hyphodontia setulosa for 2 weeks, Inoculum level, 5 g/T wood
Cooking of fungal-treated chips conducted at 14% AA charge; cooking
of reference chips conducted at 17% and 14% AA charge
[0082]
11TABLE 11 Biokraft pulping of eucalyptus with Phlebia subserialis
at reduced active alkali charge a. Pulp properties AA Charge (%) 17
14 14 14 Parameter Control Treated Control Treated P.No. 13.50
15.90 16.20 15.90 Unbleached brightness 27.1 28.1 27.3 28.4 (% PV)
Unbleached pulp yield 45.60 45.00 46.90 45.80 (%) Final brightness
87.4 88.5 88.3 89.5 (% PV) Bleach chemical consumption (kg/TP)
Elemental Cl.sub.2 37.5 37.5 46.0 46.0 NaOH 20.1 20.1 19.8 19.8
Hypo 14.6 14.6 12.6 12.6 Chlorine dioxide 6.0 6.0 6.0 6.0 b.
Strength properties Unbleached Bleached Control Treated Control
Treated Parameter 17% AA 14% AA 14% AA 17% AA 14% AA Wetness 17.0
17.0 17.5 36.0 36.0 (.degree.SR) Beating time -- -- -- 26.0 20.5
(min) Tensile 36.60 43.93 48.06 72.29 72.18 index (N m/g) Breaking
3733 4481 4902 7374 7362 length (m) Burst index 1.65 1.96 2.20 4.58
4.64 (kN/g) Tear index 6.10 7.3 7.60 7.71 8.42 (mNm.sup.2/g) Double
fold 6 10 14 72 97 (No.) Treatment of eucalyptus with Phlebia
subserialis for 2 weeks, Inoculum level, 5 g/T wood Cooking of
fungal-treated chips conducted at 14% AA charge; cooking of
reference chips conducted at 17% and 14% AA charge
[0083]
12TABLE 12 Biokraft pulping of eucalyptus with Phlebia tremellosa
at reduced active alkali charge a. Pulp properties AA Charge (%) 17
14 14 14 Parameter Control Treated Control Treated P.No. 13.89
15.90 16.00 16.30 Unbleached brightness 28.6 29.7 28.0 28.8 (% PV)
Unbleached pulp yield 46.00 45.50 46.90 45.80 (%) Final brightness
87.5 88.6 88.4 89.4 (% PV) Bleach chemical consumption (kg/TP)
Elemental Cl.sub.2 38.6 38.6 45.3 45.3 NaOH 19.1 19.1 19.0 19.0
Hypo 13.4 13.4 13.2 13.2 Chlorine dioxide 6.0 6.0 6.0 6.0 b.
Strength properties Unbleached Bleached Control Treated Control
Treated Parameter 17% AA 14% AA 14% AA 17% AA 14% AA Wetness 17.0
17.0 17.5 35.0 35.0 (.degree.SR) Beating time -- -- -- 25.0 21.0
(min) Tensile 37.60 40.10 41.00 69.50 79.10 index (N m/g) Breaking
3835 4090 4183 7089 8069 length (m) Burst index 1.64 1.84 1.92 4.88
5.34 (kN/g) Tear index 6.54 6.80 6.55 7.80 8.10 (mNm.sup.2/g)
Double fold 6 7 10 82 93 (No.) Treatment of eucalyptus with Phlebia
tremellosa for 2 weeks, Inoculum level, 5 g/T wood Cooking of
fungal-treated chips conducted at 14% AA charge; cooking of
reference chips conducted at 17% and 14% AA charge
[0084]
13TABLE 13 Biokraft pulping of eucalyptus with Phanerochaete
chrysosporium at reduced active alkali charge AA charge (%) 17 14
14 14 Parameter Control Treated Control Treated a. Pulp properties
P.No. 13.54 16.09 16.20 15.90 Unbleached brightness 27.1 28.2 27.3
28.6 (% PV) Unbleached pulp yield 45.30 46.51 46.90 46.30 (%) Final
brightness 86.6 88.0 87.8 89.0 (% PV) Bleach chemical consumption
(kg/TP) Elemental Cl.sub.2 37.6 37.6 46.0 46.0 NaOH 19.3 19.3 19.8
19.8 Hypo 14.1 14.1 12.6 12.6 Chlorine dioxide 6.0 6.0 6.0 6.0
Unbleached Bleached Control Treated Control Treated Parameter 17%
AA 14% AA 14% AA 17% AA 14% AA b. Strength properties Wetness 17.0
17.0 17.5 35.0 35.0 (.degree. SR) Beating time -- -- -- 26.0 21.0
(min) Tensile in- 36.02 42.31 44.65 74.64 76.34 dex (N m/g)
Breaking 3674 4316 4554 7614 7788 length (m) Burst index 1.64 1.84
1.96 4.95 5.16 (kN/g) Tear index 6.80 7.01 7.69 7.70 8.20 (mN
m.sup.2/g) Double fold 6 9 12 84 100 (No.) Treatment of eucalyptus
with Phanerochaete chrysosporium at 39.degree. C. for 2 weeks,
Inoculum level, 5 g/T wood Cooking of fungal-treated chips
conducted at 14% AA charge; cooking of reference chips conducted at
17% and 14% AA charge
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