U.S. patent application number 16/672727 was filed with the patent office on 2020-04-02 for microcapsule material capable of reducing pollution containing polycyclic aromatic hydrocarbon, and preparation method and appli.
The applicant listed for this patent is Guangdong Yue Gang Water Supply Co. Ltd., South China University of Technology. Invention is credited to Zhi Dang, Fucai Deng, Chuling Guo, Huixing Huang, Guining Lu, Guosheng Sun, Chen Yang, Xiaoyun Yi.
Application Number | 20200101434 16/672727 |
Document ID | / |
Family ID | 1000004500314 |
Filed Date | 2020-04-02 |
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United States Patent
Application |
20200101434 |
Kind Code |
A1 |
Dang; Zhi ; et al. |
April 2, 2020 |
Microcapsule Material Capable of Reducing Pollution Containing
Polycyclic Aromatic Hydrocarbon, and Preparation Method and
Application Thereof
Abstract
The present invention discloses a microcapsule material capable
of reducing pollution containing polycyclic aromatic hydrocarbons,
and a preparation method and application thereof. The preparation
method includes the following steps: (1) culturing Mycobacterium
gilvum CP 13 in a bacteria culture liquid to obtain a bacterial
broth, wherein the Mycobacterium gilvum CP 13 was deposited in
China General Microbiological Culture Collection Center (CGMCC) on
Jul. 22, 2013 with a CGMCC number of CGMCC No. 7963; and (2)
applying a calcium alginate and chitosan to encapsulate the
bacterial broth in a microcapsule through layer-by-layer
self-assembly to produce a microcapsule material capable of
reducing pollution containing polycyclic aromatic hydrocarbons. The
present invention produces a microcapsule material with the
microorganic activity through layer-by-layer self-assembly, which
has superior adaptability to the environment and good ability to
reduce pollution containing polycyclic aromatic hydrocarbons. The
microcapsule material of the present invention can be used in
bioremediation of industrial wastewater containing polycyclic
aromatic hydrocarbons and contaminated soil containing polycyclic
aromatic hydrocarbons.
Inventors: |
Dang; Zhi; (Guangzhou,
CN) ; Yang; Chen; (Guangzhou, CN) ; Deng;
Fucai; (Gunagzhou, CN) ; Sun; Guosheng;
(Guangzhou, CN) ; Huang; Huixing; (Guangzhou,
CN) ; Guo; Chuling; (Guangzhou, CN) ; Lu;
Guining; (Guangzhou, CN) ; Yi; Xiaoyun;
(Guangzhou, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
South China University of Technology
Guangdong Yue Gang Water Supply Co. Ltd. |
Guangdong
Shenzhen |
|
CN
CN |
|
|
Family ID: |
1000004500314 |
Appl. No.: |
16/672727 |
Filed: |
November 4, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
15758442 |
Mar 8, 2018 |
10493418 |
|
|
PCT/CN2015/100076 |
Dec 31, 2015 |
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16672727 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C02F 3/34 20130101; B01J
13/04 20130101; C12N 11/10 20130101; B09C 1/10 20130101; C12R 1/32
20130101; C12N 1/20 20130101; B01J 13/02 20130101; C02F 3/344
20130101; C02F 2101/327 20130101 |
International
Class: |
B01J 13/02 20060101
B01J013/02; B01J 13/04 20060101 B01J013/04; C02F 3/34 20060101
C02F003/34; C12R 1/32 20060101 C12R001/32; B09C 1/10 20060101
B09C001/10; C12N 11/10 20060101 C12N011/10; C12N 1/20 20060101
C12N001/20 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 9, 2015 |
CN |
201510571244.X |
Claims
1. A microcapsule material capable of reducing pollution containing
polycyclic aromatic hydrocarbons prepared by the method comprising:
(1) culturing Mycobacterium gilvum CP 13 in a bacteria culture
liquid to obtain a bacterial broth; and (2) encapsulating the
bacterial broth in the microcapsules by applying a calcium alginate
and chitosan to the bacterial broth through layer-by-layer
self-assembly to produce a microcapsule material capable of
reducing pollution containing polycyclic aromatic hydrocarbons.
2. A method of degrading polycyclic aromatic hydrocarbons present
in at least one of water or soil, wherein the method comprises
applying the microcapsule material of claim 1 to the water and/or
soil.
3. The method according to claim 2, wherein the polycyclic aromatic
hydrocarbons are pyrene.
4. The method according to claim 2, wherein the microcapsule
material is added to water in an amount of 0.1 g of the
microcapsule material per 20 ml of water.
5. The method according to claim 2, wherein the microcapsule
material is added to soil in an amount of 2.0 g of the microcapsule
material per 400 g of soil.
6. The method according to claim 2, wherein the microcapsule
material is added to water in an amount of 0.1 g of the
microcapsule material per 20 ml of water and added to soil in an
amount of 2.0 g of the microcapsule material per 400 g of soil.
7. The microcapsule material of claim 1, wherein the bacteria
culture liquid is nutrient broth medium, and wherein the bacteria
culture liquid further comprises beef extract 3 g/L, peptone 10
g/L, NaCl 5 g/L, agar 20 g/L, and has a pH in the range of 7.0 to
7.2.
8. The microcapsule material of claim 1, wherein the step (2) of
the method further comprises: adding chitosan into the bacterial
broth so that the chitosan is deposited on a surface of bacteria,
adding the calcium alginate to the bacterial broth so that the
calcium alginate is deposited on a surface of chitosan; and
repeating these steps 2-3 times, thereby encapsulating the
bacterial broth in the microcapsules.
9. The microcapsule material of claim 8, wherein the concentrations
of chitosan and the calcium alginate are each in a range of 0.1-2.0
g/L.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a division of U.S. patent application
Ser. No. 15/758,442, filed on Mar. 8, 2018, which is the United
States National Phase of International Application No.
PCT/CN2015/100076 filed Dec. 31, 2015, which claims priority to
Chinese Patent Application No. 201510571244.X filed Sep. 9, 2015,
the disclosures of which are hereby incorporated in their entirety
by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention belongs to the technical field of
bioremediation of environmental pollutants, in particular to the
preparation of a microcapsule material for highly efficient
degradation of polycyclic aromatic hydrocarbons and its application
in the bioremediation of wastewater and the remediation of
contaminated soil.
Description of Related Art
[0003] Polycyclic aromatic hydrocarbons, as a kind of common
organic pollutants in the environment, usually refer to a class of
fused ring compounds containing two or more benzene rings and
arranged in a linear, angular or clustered manner, and they have
bioaccumulation and environmental durability as well as
carcinogenic, teratogenic and mutagenic effects (three inductions),
posing a huge threat to the biosecurity and human health in
nature.
[0004] Most of the polycyclic aromatic hydrocarbons in the
environment are accumulated in soil. Where appropriate, they may
migrate to other environmental media, expanding the range of
pollution and changing the route of exposure. The polycyclic
aromatic hydrocarbons in farmland, mostly caused by sewage
irrigation, can be passed through crops in the form of a biological
chain, and may cause damage to the human body after their
accumulation therein. It is very important and urgent to
rehabilitate the farmland contaminated with polycyclic aromatic
hydrocarbons, especially to strengthen the rehabilitation of
long-term contaminated soil.
[0005] In the polycyclic aromatic hydrocarbons that are common in
the polluted environment and difficult to be degraded, since the
ketone metabolites of pyrene are more toxic and mutagenic than
their parents, pyrene is often used as an indicator to monitor the
pollution of polycyclic aromatic hydrocarbons and a model molecule
of biodegradation of other polycyclic aromatic hydrocarbons, thus
becoming a representative of polycyclic aromatic hydrocarbons.
SUMMARY OF THE INVENTION
[0006] Using microbial treatment to solve the pollution problem of
polycyclic aromatic hydrocarbons in the environment, having been
widely accepted, has good effects, low cost, less secondary
pollution and other advantages, and is thus a kind of
bioremediation technology with low consumption, high efficiency and
environmental safety. Currently, by artificial enrichment culture
and other technologies, people have isolated many microorganisms
that can degrade or transform some kind of polycyclic aromatic
hydrocarbons. However, due to the vicious competition of indigenous
bacteria or the change of environmental conditions, etc., free
microorganisms are often difficult to adapt to the actual
rehabilitation environment and cannot achieve the desired
rehabilitative effects. Therefore, the development of biomaterials
with high environmental adaptability and high efficiency of
degrading polycyclic aromatic hydrocarbons has become one of the
hot issues in the research on the abatement and remediation of
polluted environment.
CONTENTS OF THE INVENTION
[0007] A purpose of the present invention is to provide a
microcapsule material capable of reducing pollution containing
polycyclic aromatic hydrocarbons, and a preparation method and
application thereof.
[0008] In order to achieve the purpose of the present invention,
the following technical solution is adopted:
[0009] A preparation method of a microcapsule material capable of
reducing pollution containing polycyclic aromatic hydrocarbons is
provided, comprising the following steps:
[0010] (1) culturing Mycobacterium gilvum CP 13 in a bacteria
culture liquid to obtain a bacterial broth, wherein the
Mycobacterium gilvum CP 13 was deposited in China General
Microbiological Culture Collection Center (CGMCC) on Jul. 22, 2013
with a CGMCC number of CGMCC No. 7963; and
[0011] (2) applying a calcium alginate and chitosan to encapsulate
the bacterial broth in a microcapsule through layer-by-layer
self-assembly to produce a microcapsule material capable of
reducing pollution containing polycyclic aromatic hydrocarbons.
[0012] The bacteria culture liquid is nutrient broth medium having
the following composition and dosage: beef extract 3 g/L, peptone
10 g/L, NaCl 5 g/L, agar 20 g/L, and a pH adjusted to 7.0-7.2.
[0013] The step (2) of encapsulating the bacterial broth in a
microcapsule comprises the following steps: adding chitosan to the
bacterial broth so that chitosan is deposited on the surface of
bacteria, and then adding calcium alginate solution so that calcium
alginate is further deposited on the surface of chitosan; repeating
the operations above 2-3 times so that the bacterial broth can be
encapsulated in the microcapsule.
[0014] The concentrations of chitosan and calcium alginate are both
0.1-2.0 g/L.
[0015] The microcapsule material capable of reducing pollution
containing polycyclic aromatic hydrocarbons prepared by the above
method is applied to degradation of polycyclic aromatic
hydrocarbons in water and soil.
[0016] The polycyclic aromatic hydrocarbons are pyrene.
[0017] The microcapsule material is added in water in an amount of
0.1 g of the microcapsule material per 20 ml of water and added in
soil in an amount of 2.0 g of the microcapsule material per 400 g
of soil.
[0018] The present invention has the following advantages compared
to the prior art:
[0019] (1) The microcapsule material of the present invention has
strong adaptability to harsh environments and can be adapted to a
wide range of pH and low and high temperature environments. Having
superior ability to remove polycyclic aromatic hydrocarbons, the
microcapsule material is capable of removing more than 81% of high
concentration of polycyclic aromatic hydrocarbon pyrene contained
in vegetable soil (120 mg of polycyclic aromatic hydrocarbon pyrene
per kilogram of vegetable soil) within 40 days at room temperature
(20.degree. C..+-.5.degree. C.), and removing more than 80% of
pyrene in water (up to 50 mg/L) within 7 days, with its degradation
performance not affected in strong acidity and alkalinity (pH 3-10)
and at high and low temperatures (10.degree. C.-40.degree. C.) and
under other harsh conditions. It can be used for treatment of
industrial wastewater containing polycyclic aromatic hydrocarbons
and soil bioremediation.
[0020] (2) The microcapsule material of the present invention
consists of an environmentally safe bacterium Mycobacterium gilvum
CP 13 that degrades a variety of tricyclic polycyclic aromatic
hydrocarbons and tetracyclic polycyclic aromatic hydrocarbons. The
microcapsule material is capable of removing a variety of
polycyclic aromatic hydrocarbons in soil, suitable for southern
rice field soil, vegetable soil, red soil and other soils, with the
significant effect of remediating soil contaminated by polycyclic
aromatic hydrocarbons.
[0021] The Mycobacterium gilvum CP 13 provided by the present
invention was deposited on Jul. 22, 2013 in China General
Microbiological Culture Collection Center (CGMCC) (located in
Institute of Microbiology, Chinese Academy of Sciences, No. 3, 1
Beichen West Road, Chaoyang District, Beijing, P.R. China) with a
CGMCC number of CGMCC No. 7963. This strain has been disclosed in a
patent with a publication number CN102824897A and belongs to the
prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1. Effects of different initial concentrations of
pyrene on the degradation of pyrene by the microcapsule material of
the present invention. (a) 10 mg/L, (b) 30 mg/L, and (c) 50 mg/L.
Treatment: (.smallcircle.) a blank of free bacteria,
(.circle-solid.) a blank of the microcapsule material of the
present invention, (.DELTA.) free bacteria, (.right brkt-bot.) the
microcapsule material of the present invention, (.quadrature.) free
bacteria, (.box-solid.) the microcapsule material of the present
invention, (.diamond.) free bacteria, and (.diamond-solid.) the
microcapsule material of the present invention.
[0023] FIG. 2. Effects of different pH values (a) and different
temperatures (b) on the degradation of pyrene by the microcapsule
material of the present invention. Initial concentration of
pyrene=10 mg/L. Treatment: (a) (.DELTA.) free bacteria--pH 7,
(.tangle-solidup.) the microcapsule material of the present
invention--pH 7, (.quadrature.) free bacteria--pH 3, (.box-solid.)
the microcapsule material of the present invention--pH 3,
(.diamond.) free bacteria--pH 10, (.diamond-solid.) the
microcapsule material of the present invention--pH 10; (b)
(.DELTA.) free bacteria--30.degree. C., (.tangle-solidup.) the
microcapsule material of the present invention--30.degree. C.,
(.quadrature.) free bacteria--10.degree. C., (.box-solid.) the
microcapsule material of the present invention--10.degree. C.,
(.diamond.) free bacteria--40.degree. C., and (.diamond-solid.) the
microcapsule material of the present invention--40.degree. C.
[0024] FIG. 3. Changes of the removal rate of pyrene in soil in the
process of remediation of pyrene contaminated soil by the
microcapsule material of the present invention. The initial
concentration of pyrene=120 mg/kg. Treatment: (.smallcircle.) free
bacteria, and () the microcapsule material of the present
invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0025] The present invention will be further described below in
detail with reference to specific examples; however, the
embodiments of the present invention are not limited thereto, and
process parameters not specifically given can be determined by
referring to conventional techniques.
Example 1
[0026] Preparation of the Microcapsule Material of the Present
Invention Capable of Degrading Polycyclic Aromatic Hydrocarbons
[0027] A method for culturing Mycobacterium gilvum CP 13 strain of
the present invention is as follows:
[0028] Respectively performing streak inoculation of the CP 13
strains in beef juice peptone medium, and culturing at 28.degree.
C.-30.degree. C. for 48 h; then respectively inoculating them into
a 500 mL flask, and culturing at 30.degree. C. and 150 r/min for 12
h; and finally inoculating them into a 5 L seed tank in accordance
with an inoculum concentration of 5%, and culturing at 180 r/min,
pH 7.5 and a ventilatory capacity of 5 L/min for 24 h.
[0029] Composition and dosage of the nutrient broth medium are as
follows (g/L): Beef extract 3, peptone 10, NaCl 5, agar 20, and a
pH adjusted to 7.0-7.2.
[0030] The specific steps are as follows: (1) Culturing
Mycobacterium gilvum CP 13 in a bacteria culture liquid to obtain a
bacterial broth, (2) adding 20 ml of 0.2 g/L polycation (chitosan)
to the bacterial broth so that polycation is deposited on the
surface of bacteria, and then adding the same volume and
concentration of polyanion (calcium alginate) solution so that
polyanion is further deposited on the surface of the chitosan.
Repeating the operations above 2-3 times so that the bacterial
broth can be encapsulated in the microcapsule. The
bacteria-immobilized microcapsules are thus prepared. They are
sealed in sterile bags and stored in a refrigerator at 4.degree.
C.
Example 2
[0031] Inoculating the microcapsule material prepared in Example 1
at a ratio of 0.1 g/20 ml to a MSM culture solution with the
concentration of pyrene at 10 mg/L; taking a pyrene-containing MSM
medium without the microcapsule material as a blank and placing it
in a shaker at 30.degree. C., culturing in darkness while shaking
at 150 r/min, and then determining the residual amount of pyrene in
the culture solution. The formulation of the MSM culture solution:
100 mg/L (NH.sub.4).sub.2SO.sub.4, 20 mg/L MgSO.sub.4.7H.sub.2O, 10
mg/L CaCl.sub.2.2H.sub.2O; trace elements: 1.2 mg/L
FeSO.sub.4.7H.sub.2O, 0.3 mg/L MnSO.sub.4.H.sub.2O, 0.3 mg/L
ZnSO.sub.4.7H.sub.2O, 0.1 mg/L CoSO.sub.4.7H.sub.2O, 0.1 mg/L
(NH.sub.4).sub.6Mo.sub.7O.sub.24.4H.sub.2O; phosphate buffer
solution: 2.5 g/L K.sub.2HPO.sub.3, 0.77 g/L KH.sub.2PO.sub.3, pH
7.2-7.4.
[0032] As can be seen from FIG. 1, in the experimental
concentration range, the efficiency of removal of PYR by the
microcapsule material is higher. At the initial pyrene
concentrations of 10 mg/L, 30 mg/L and 50 mg/L, respectively, the
3d removal rates are increased from 60%, 40%, 20% by the free CP 13
bacteria to 95%, 65%, 55% by the microcapsule material,
respectively. In the case of high concentration (such as 50 mg/L),
the microcapsule material is more advantageous.
Example 3
[0033] Inoculating the microcapsule material prepared in Example 1
at a ratio of 0.1 g/20 ml to a MSM culture solution with the
concentration of pyrene at 10 mg/L; taking a pyrene-containing MSM
medium without the microcapsule material as a blank and free
bacteria as a control and placing them in a shaker at 30.degree.
C., culturing in darkness while shaking at 150 r/min, and then
determining the residual amount of pyrene in the culture solution.
As can be seen from FIG. 2, the microcapsule material of the
present invention can effectively degrade polycyclic aromatic
hydrocarbon pyrene under the conditions of pH 3-10. Especially in
the acidic case of pH 3, the removal rate of free bacteria is only
15%, while the removal rate of the microcapsule material of the
present invention can still be maintained at 95% or more. As can be
seen, the microcapsule material of the present invention has a
broader range of pH adaptation than free bacteria. Besides, the
microcapsule material of the present invention can effectively
degrade polycyclic aromatic hydrocarbon pyrene at a temperature of
10.degree. C.-40.degree. C. Similarly, in the case of ambient
temperatures as low as 10.degree. C., the 4d removal rate by the
free bacteria is only about 17%, while the 4d removal rate by the
microcapsule material of the present invention can reach 80%. At
40.degree. C., the 4d removal rate of the microcapsule material of
the present invention is maintained at 80%, much higher than 40% by
the free bacteria within the same duration. It can be seen that the
microcapsule material of the present invention has better thermal
stability than the free bacteria.
[0034] This example shows that the microcapsule material of the
present invention capable of degrading polycyclic aromatic
hydrocarbons can degrade pyrene well in a wide pH range of acidic,
neutral and alkaline conditions and at 10.degree. C.-40.degree. C.,
ensuring its application at different pHs and in low and high
temperature environments.
Example 4
[0035] Experiment on Remediation of Pyrene Contaminated Soil by the
Microcapsule Material of the Present Invention
[0036] Adding 400 g of non-sterile soil, to which pyrene has been
added at 120 mg of pyrene per kilogram of soil, to a 500 ml beaker,
and adding 2.0 g of the microcapsule material of Example 1 to the
soil so that the initial inoculum is 10.sup.7 CFU per gram of soil.
Using free CP 13 as a control at the same amount of 10.sup.7 CFU
per gram of soil, and incubating in an incubator at 30.degree. C.
Sampling to determine the residual amount of pyrene in the soil
after culturing for 6 d, 10 d, 20 d, 40 d.
[0037] As indicated by the results in FIG. 3, after using the
microcapsule material of the present invention to treat the soil
containing pyrene at 120 mg of pyrene per kilogram of soil for 40
days, the removal rate of pyrene can reach 81%, while here the
degradation rate of the control using free bacteria is only
42%.
* * * * *