Chemistry: molecular biology and microbiology – Process of utilizing an enzyme or micro-organism to destroy... – Destruction of hazardous or toxic waste
Reexamination Certificate
2000-12-08
2004-06-22
Beisner, William H. (Department: 1744)
Chemistry: molecular biology and microbiology
Process of utilizing an enzyme or micro-organism to destroy...
Destruction of hazardous or toxic waste
C435S262000, C435S177000, C435S178000, C435S182000
Reexamination Certificate
active
06753179
ABSTRACT:
TECHNICAL FIELD
The present invention relates to methods for purifying an environmental pollutant using microorganisms. More specifically, the present invention relates to purification methods wherein an environmental pollutant is concentrated in the presence of microorganisms while being prevented from reducing the biological activity of the microorganisms, to perform biodegradation and purification (assimilation or degradation) of the pollutant more efficiently.
BACKGROUND ART
Conventionally, environmental pollutants discharged as wastes are disposed of by incineration, landfill, ocean dumping, chemical treatment, physical treatment, biological treatment, etc. Of these disposal methods, biological treatment is broadly divided according to the environmental pollutant to be disposed of, into two types of treatment, i.e., treatment of liquid wastes such as sewage and industrial waste water, and treatment of solid wastes such as chemical products (e.g., plastics) and garbage. Since the biological treatment has the advantage of less secondary pollution than other disposal methods, much is expected of the biological treatment as a method for purifying environmental pollutants.
The biological treatment, however, has the problem that it depends on the biological ability of microorganisms, and thus its efficiency of purifying environmental pollutants greatly varies according to the microorganisms used. For example, when waste water containing only a trace amount of a target environmental pollutant is purified using microorganisms, components other than the target pollutant, which are present in great amounts, cause growth or proliferation of other species of microorganisms which assimilate or degrade such components. As a result, the microorganisms capable of biodegrading the target pollutant are inhibited from proliferating, failing to sufficiently purify the pollutant. Further, an environmental pollutant, when present at a certain concentration or higher, inhibits growth of microorganisms. It is therefore difficult to biologically treat a high concentration of environmental pollutant using microorganisms.
Recently, therefore, methods have been employed which utilize a pure culture of microorganisms with high assimilating or degrading ability to environmental pollutants, to increase the efficiency of biological purification treatment. Further, studies have been recently made on use of microorganisms with high assimilating or degrading ability as immobilized on an inorganic or organic support.
The most important problem remaining with the biological treatment is how to cause microorganisms with high assimilating or degrading ability to capture environmental pollutants efficiently and to assimilate or degrade the pollutants effectively. To solve this problem, a method has been studied in which a porous support (e.g., activated carbon or zeolite) having microorganisms adsorbed and immobilized thereon, is contacted with and allowed to adsorb an environmental pollutant diluted to a concentration that does not inhibit growth of the microorganisms, whereby the microorganisms act on the environmental pollutant in the pores of the support. However, the pollutant adsorbed by this method will have a high concentration in the pores of the support and inhibit growth of the microorganisms. Thus, this method fails to achieve an expected level of assimilation or degradation of the pollutant.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a method for purifying an environmental pollutant by biological treatment with microorganisms, wherein the pollutant is efficiently concentrated to a high concentration, but exerts substantially no effect on the biological activity of the microorganisms used for biodegradation of the pollutant, so that the pollutant is purified (assimilated or degraded) effectively. Another object of the present invention is to provide a microbial treatment agent useful for effectively performing the method for purification (assimilation or degradation) of an environmental pollutant.
The present inventors conducted extensive research to achieve the above objects, and found that when the microorganisms for use in biological treatment are incorporated into a microorganism-produced polymer, the microorganisms are not severely inhibited from growing even in the presence of a high concentration of a pollutant, and retain their biological activity necessary for assimilation or degradation of the pollutant. They further found that when the microorganism-produced polymer coexists with an environmental pollutant, the pollutant is incorporated into the polymer and concentrated efficiently. The present inventors conducted further research based on the above findings, and confirmed that when an environmental pollutant as incorporated in a microorganism-produced polymer coexists with microorganisms capable of assimilating or degrading the pollutant, a high concentration of the pollutant can be efficiently purified (assimilated or degraded) without inhibiting the biological activity of the microorganisms. The present invention has been accomplished based on these findings.
The present invention provides methods for purification treatment of an environmental pollutant using microorganisms, as described in the following items (1) to (9).
(1) A method for purification treatment of an environmental pollutant, wherein the environmental pollutant and microorganisms are made to coexist with each other as incorporated in a microorganism-produced polymer.
(2) The method according to the item (1), wherein the microorganism-produced polymer is a polymer containing a sugar component in which fructofuranosyl group(s) is/are bonded to a fructosyl group at the &bgr;-2,6 position.
(3) The method according to the item (1), wherein the microorganism-produced polymer is a polyamino acid containing at least one amino acid selected from the group consisting of glutamic acid, leucine, alanine and phenylalanine.
(4) The method according to the item (1), wherein the microorganism-produced polymer is a polyamino acid substantially consisting of glutamic acid, leucine, alanine or phenylamine.
(5) The method according to the item (1), wherein the microorganism-produced polymer is a polyamino acid containing at least 65% of one amino acid selected from the group consisting of glutamic acid, leucine, alanine and phenylalanine.
(6) The method according to the item (1), wherein the microorganism-produced polymer is used in the presence of a cationic inorganic salt.
(7) The method according to the item (6), wherein the cationic inorganic salt is at least one member selected from the group consisting of aluminum chloride, aluminum sulfate, sodium aluminate, calcium chloride, ferrous sulfate, ferric chloride, iron(III) sulfate and copper chloride.
(8) The method according to the item (1), wherein the microorganisms are at least one member selected from the group consisting of the genera Pseudomonas, Rhodococcus, Aeromonas, Rhizobium, Sphingomonas, Arthrobacter, Frateuria, Flavobacterium and Bacillus.
(9) The method according to the item (1), wherein the environmental pollutant is at least one member selected from the group consisting of polychlorinated biphenyls, dioxins, dichloroethylenes, dichloroethanes, trichloroethylenes, trichloroethanes, mercury and its compounds, and selenium and its compounds.
The present invention also provides microbial treatment agents useful for the above methods for purifying an environmental pollutant:
(10) A microbial treatment agent comprising microorganisms incorporated in a microorganism-produced polymer.
(11) The microbial treatment agent according to the item (10), wherein the microorganisms are at least one member selected from the group consisting of the genera Pseudomonas, Rhodococcus, Aeromonas, Rhizobium, Sphingomonas, Arthrobacter, Frateuria, Flavobacterium and Bacillus.
(12) The microbial treatment agent according to the item (10), wherein the microorganisms are a mixture of at least two members selected from the group consisting of the genera Pseudomona
Allmighty Co., Ltd.
Armstrong Kratz Quintos Hanson & Brooks, LLP
Beisner William H.
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