Chemistry: molecular biology and microbiology – Micro-organism – per se ; compositions thereof; proces of... – Bacteria or actinomycetales; media therefor
Reexamination Certificate
1999-02-19
2001-01-09
Lilling, Herbert J. (Department: 1651)
Chemistry: molecular biology and microbiology
Micro-organism, per se ; compositions thereof; proces of...
Bacteria or actinomycetales; media therefor
C435S262500
Reexamination Certificate
active
06171844
ABSTRACT:
FIELD OF INVENTION
The present invention relates to new microorganisms which efficiently decompose organic halogenated compounds such as trichloroethylene, and to a method for decomposing organic halogenated compounds, specifically trichloroethylene in the soil, the underground water, or waste waters.
BACKGROUND OF INVENTION
In recent years, industrial utilization of organic solvents has been producing environmental polution problems by discharge of these compounds or waste waters containing these compounds in many parts of the nation. In particular, soil polution by organic chlorinated compounds is a major social problem, and the technology of repairing the contaminated soil has become more essential. The purification method of the contaminated soil includes physical methods and biological methods.
The physical treatment methods include the air-stripping method (a method of purging air into the contaminated soil which was excavated in order to volatize organic chlorinated compounds contained therein, and of removing them by adsorption on activated charcoal), and vacuum extraction methods (a method in which pipes are driven into the contaminated soil to create the state of reduced pressure so that the organic chlorinated compounds therein are volatized and extracted from the soil). However, these methods require an enormous power for purging the air etc., and have the drawbacks that the former methods require excavation of the soil, while in the latter the extraction efficiency is low and purification does not proceed smoothly under the low concentration of the contaminats. Furthermore, both methods only absorb the contaminating substances to the activated charcoal and therefore require a separate means to detoxicate the contaminating substances.
It has been reported recently that the biological treatment method which is under development utilizes the ability of microorganisms to decompose substances and can completely decompose or detoxicate the contaminating substances, and besides less energy is needed for the treatment as compared with the physical means. Moreover, the biological means permits purification even at low concentrations of contaminants and accordingly expectations on the method are great as a low-cost method for soil purification. The known biological methods include the solid-phase treatment (the excavated soil is mixed with phosphorus, nitrogen, microorganisms etc. to promote decomposition of the contaminating substances by the microorganisms), the slurry treatment method (the excavated soil is mixed with water, phosphorus, nitrogen, microorganisms etc. to treat in the liquid form to promote purification speed of the contaminating substances by the microorganisms), and the on-site treatment method (methane, the air, phosphorus, and nitrogen are injected into the soil without excavating the soil to promote decomposition of the contaminating substances by the microorganisms).
Of the conventionally used biological treatment methods, the solid-phase treatment method and the slurry treatment method require excavation of the soil and besides have a narrow range of application, and the cost for treatment and equipment is relatively high.
On the other hand, the on-site treatment method in which indegenous microorganisms are performed as degraders is less expensive in treatment and equipment compared with the methods described above, and can be applied on a wider range. But, under the condition that the absolute number of microorganisms in the soil is small, the purification rate of the on-site treatment decreases. Especially in the case of the compounds refractory to decomposition such as organic chlorinated compounds, purification is impossible when there are no living microorganisms which can decompose said contaminants in the soil. In such cases, it is believed that inoculation of the microorganisms having the ability of decomposing organic chlorinated compounds into the soil is essential for enhancement of the purification late of soil.
Known microorganisms which decompose trichloroethylene include
Methylosinus tricosporium
OB3 (Japanese Unexamined Patent Publication (Kohyo) No. 4(1992)-501667, Japanese Unexamined Patent Publication No. 5(1993)-212371), and
Methylosinus tricosporium
TUKUBA (Japanese Unexamined Patent Publication No. 2(1990)-92274, Japanese Unexamined Patent Publication No. 3(1991)-292970) which are methane-degradatating organisms,
Pseudomonas putida
F1 (Japanese Unexamined Patent Publication No. 64(1989)-34499),
Pseudomonas putida
BH (Fujita et al.; Chemical Engineering, 39(6):494-498, 1994),
Pseudomonas putida
UC-R5, UC-P2 (Japanese Unexamined Patent Publication No. 62(1987)-84780),
Pseudomonas putida
KWI-9 (Japanese Unexamined Patent Publication No. 6(1994)-70753),
Pseudomonas mendocina
KR1 (Japanese Unexamined Patent Publication No. 2(1990)-503866, 5(1993)-502593),
Pseudomonas cepacia
G4 (Japanese Unexamined Patent Publication No. 4(1992)-502277), and
Pseudomonas cepacia
KK01 (Japanese Unexamined Patent Publication No. 6(1994)-296711) which belong to the genus Pseudomonas,
Alcaligenes eutropus
JMP134 (A. R. Harker, Appl. Environ. Microbiol., 56(4):1179-1181, 1990),
Alcaligenes eutropus
KS01 (Japanese Unexamined Patent Publication No. 7(1995)-123976),
Nitrosomonas europaea
(D. Arciero et al., Biochem. Biophys. Res. Commun., 159(2):640-643, 1989) which is an ammonia-oxidizing bacterium, Corynebacterium J1 (Japanese Unexamined Patent Publication No. 8(1996)-66182) and the like.
The trichloroethylene-decomposing ability of these known microorganisms is not very high and most of these microorganisms can decompose 5 ppm of trichloroethylene in the liquid culture only. Furthermore, since decomposing ability of trichloroethylene in a special environment as the soil is required, it is necessary that the microorganism to be used for bioremediation not only has a sufficient ability of decomposing trichloroethylene but also can remain decomposing ability of trichloroethylene even in the soil. However, most of the known microorganisms are insufficient in this respect.
It is reported that
Pseudomonas cepacia
KK01 can decompose trichloroethylene at an initial concentration of 30 ppm to 15 ppm in the liquid culture, and trichloroethylene at an initial concentration of 5 ppm to 1 ppm in the soil (Japanese Unexamined Patent Publication No.-6(1994)-296711). Furthermore, it is reported that
Alcaligenes eutropus
KS01 can decompose trichloroethylene at an initial concentration of 50 ppm to below the level of detection in the liquid culture, and trichloroethylene at an initial concentration of 1 ppm to below the level of detection limit in the soil (Japanese Unexamined Patent Publication No. 7(1995)-123976).
It has been confirmed that these microorganisms have a higher decomposing ability than the conventional microorganisms and that these abilities can be exhibited even in the soil. However, addition of at least one or more than one aromatic compound is needed to the soil environment for induction of the decomposing abilities of these microorganisms. But, the aromatic compounds themselves are contaminants and therefore have a risk of causing a secondary pollution. It is a great challenge to be solved for practical application, therefore, to obtain a microorganism which enables an aromatic compound, when added, to be completely decomposed and removed together with trichloroethylene, or which permits decomposition of trichloroethylene without addition of an aromatic compound.
Accordingly, in order to put the biological purification of trichloroethylene into practical use, it has been desired to obtain a microorganism which has a high decomposing ability, and which enables an aromatic compound, when added, to be completely decomposed and removed together with trichloroethylene, or which permits decomposition of trichloroethylene without addition of an aromatic compound.
Furthermore, in many cases it is extremely difficult to increase the density of a microorganism to the level commensurate with its desired treatment capacity, because the
Asami Osamu
Kimura Toshiaki
Miyata Masami
Numata Koichi
Oda Yasushi
Kenyon & Kenyon
Lilling Herbert J.
Toyota Jidosha & Kabushiki Kaisha
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