Isolation of butyrate-utilizing bacteria from thermophilic and mesophilic methane-producing ecosystems
The ability of various ecosystems to convert butyrate to methane was studied in order to isolate the bacteria responsible for the conversion. When thermophilic digester sludge was enriched with butyrate, methane was produced without a lag period. Marine sediments enriched with butyrate required a 2-week incubation period before methanogenesis began. A thermophilic digester was studied in more detail and found by most-probable-number enumeration to have ca. 5 x 10/sup 6/ butyrate-utilizing bactera/ml of sludge. A thermophilic butyrate-utilizing bacterium was isolated in coculture with Methanobacterium thermoautotrophicum and a Methanosarcina sp. This bacterium was a gram-negative, slightly curved rod that occurred singly, was nonmotile, and did not appear to produce spores. The thermophilic digester was infused with butyrate at the rate of 10 ..mu..moles/ml of sludge per day. Biogas production increased by 150%, with the percentage of methane increasing from 58% to 68%. Acetate, propionate, and butyrate did not accumulate. Butyrate-utilizing enrichments from mesophilic ecosystems were used in obtaining cocultures of butyrate-utilizing bacteria. These cocultures served as inocula for attempts to isolate pure cultures of butyrate-utilizing bacteria by use of hydrogenase-containing membrane fragments of Escherichia coli. After a 3-week incubation period, colonies appeared only in inoculated tubes that contained membrane fragments and butyrate.
- OSTI ID:
- 5766077
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ANAEROBIC DIGESTION
BACTERIA
BIOCHEMISTRY
BIOCONVERSION
BIOGAS PROCESS
BUTYRIC ACID
CARBOXYLIC ACIDS
CHEMISTRY
DIGESTION
ESCHERICHIA COLI
MANAGEMENT
METHANOGENIC BACTERIA
MICROORGANISMS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
PROCESSING
SEDIMENTS
SLUDGES
WASTE MANAGEMENT
WASTE PROCESSING