Influence of endogenous and exogenous electron donors and trichloroethylene oxidation toxicity on trichloroethylene oxidation by methanotrophic cultures from a groundwater aquifer

Journal Article · Tue Jan 01 00:00:00 EST 1991 · Applied and Environmental Microbiology; (USA)

OSTI ID:5804535

Henry, S M; Grbic-Galic, D ^[1]

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1. Stanford Univ., CA (USA)

Trichloroethylene (TCE)-transforming aquifer methanotrophs were evaluated for the influence of TCE oxidation toxicity and the effect of reductant availability on TCE transformation rates during methane starvation. TCE oxidation at relatively low (6 mg liter{sup {minus}1}) TCE concentrations significantly reduced subsequent methane utilization in mixed and pure cultures tested and reduced the number of viable cells in the pure culture Methylomonas sp. strain MM2 by an order of magnitude. Perchloroethylene, tested at the same concentration, had no effect on the cultures. Neither the TCE itself nor the aqueous intermediates were responsible for the toxic effect, and it is suggested that TCE oxidation toxicity may have resulted from reactive intermediates that attacked cellular macromolecules. During starvation, all methanotrophs tested exhibited a decline in TCE transformation rates, and this decline followed exponential decay. Formate, provided as an exogenous electron donor, increased TCE transformation rates in Methylomonas sp. strain MM2, but not in mixed culture MM1 or unidentified isolate, CSC-1. Mixed culture MM2 did not transform TCE after 15 h of starvation, but mixed cultures MM1 and MM3 did. The methanotrophs in mixed cultures MM1 and MM3, and the unidentified isolate CSC-1 that was isolated from mixed culture MM1 contained lipid inclusions, whereas the methanotrophs of mixed culture MM2 and Methylomonas sp. strain MM2 did not. It is proposed that lipid storage granules serve as an endogenous source of electrons for TCE oxidation during methane starvation.

• OSTI ID: 5804535
• Journal Information: Applied and Environmental Microbiology; (USA), Vol. 57:1; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
CHLORINATED ALIPHATIC HYDROCARBONS
BIODEGRADATION
METHANOTROPHIC BACTERIA
PRODUCTIVITY
AQUIFERS
GROUND WATER
MITIGATION
BACTERIA
CHEMICAL REACTIONS
DECOMPOSITION
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN COMPOUNDS
MICROORGANISMS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXYGEN COMPOUNDS
WATER
540320* - Environment
Aquatic- Chemicals Monitoring & Transport- (1990-)