Formation and fate of fermentation products in hot spring cyanobacterial mats
The fate of representative fermentation products (acetate, propionate, butyrate, lactate, and ethanol) in hot spring cyanobacterial mats was investigated. The major fate during incubations in the light was photoassimilation by filamentous bacteria resembling Chloroflexus aurantiacus. Some metabolism of all compounds occurred under dark aerobic conditions. Under dark anaerobic conditions, only lactate was oxidized extensively to carbon dioxide. Extended preincubation under dark anaerobic conditions did not enhance anaerobic catabolism of acetate, propionate, or ethanol. Acetogenesis of butyrate was suggested by the hydrogen sensitivity of butyrate conversion to acetate and by the enrichment of butyrate-degrading acetogenic bacteria. Accumulation of fermentation products which were not catabolized under dark anaerobic conditions revealed their importance. Acetate and propionate were the major fermentation products which accumulated in samples collected at temperatures ranging from 50 to 70/sup 0/C. Other organic acids and alcohols accumulated to a much lesser extent. Fermentation occurred mainly in the top 4 mm of the mat. Exposure to light decreased the accumulation of acetate and presumably of other fermentation products. The importance of interspecies hydrogen transfer was investigated by comparing fermentation product accumulation at a 65/sup 0/C site, with naturally high hydrogen levels, and a 55/sup 0/C site, where active methanogenesis prevented significant hydrogen accumulation. There was a greater relative accumulation of reduced products, notably ethanol, in the 65/sup 2/C mat.
- Research Organization:
- Montana State Univ., Bozeman (USA)
- OSTI ID:
- 7015400
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 53:10
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CYANOBACTERIA
GROWTH
ETHANOL
YIELDS
ORGANIC MATTER
FERMENTATION
ACETATES
AEROBIC CONDITIONS
ANAEROBIC CONDITIONS
BUTYRIC ACID
HOT SPRINGS
LACTATES
PROPIONIC ACID
ALCOHOLS
BIOCONVERSION
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
HYDROXY COMPOUNDS
MICROORGANISMS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
THERMAL SPRINGS
WATER SPRINGS
090222* - Alcohol Fuels- Preparation from Wastes or Biomass- (1976-1989)