Influence of pH on terminal carbon metabolism in anoxic sediments from a mildly acidic lake
The carbon and electron flow pathways and the bacterial populations responsible for transformation of H/sub 2/-CO/sub 2/, formate, methanol, methylamine, acetate, glycine, ethanol, and lactate were examined in sediments collected from Knaack Lake, Wisconsin. The sediments were 60% organic matter (pH 6.2) and did not display detectable sulfate-reducing activity, but they contained the following average concentration (in micromoles per liter of sediment) of metabolites and end products: sulfide, 10; methane, 1540; CO/sub 2/, 3950; formate, 25; acetate, 157; ethanol, 174; and lactate, 138. Methane was produced predominately from acetate, and only 4% of the total CH/sub 4/ was derived from CO/sub 2/. Methanogenesis was limited by low environmental temperature and sulfide levels and more importantly by low pH. Increasing in vitro pH to neutral values enhanced total methane production rates and the percentage of CO/sub 2/ transformed to methane but did not alter the amount of /sup 14/CO/sub 2/ produced from (2-/sup 14/C)acetate (approx. 24%). Analysis of both carbon transformation parameters with /sup 14/C-labeled tracers and bacterial trophic group enumerations indicated that methanogenesis from acetate and both heterolactic- and acetic acid-producing fermentations were important to the anaerobic digestion process.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 5956981
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 48:6; ISSN AEMID
- Country of Publication:
- United States
- Language:
- English
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54 ENVIRONMENTAL SCIENCES
550701 -- Microbiology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETATES
ALCOHOLS
ALKANES
AMINES
AMINO ACIDS
ANAEROBIC DIGESTION
BIOCONVERSION
BIOSYNTHESIS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CHALCOGENIDES
DATA
DIGESTION
ELEMENTS
ETHANOL
EXPERIMENTAL DATA
FEDERAL REGION V
FERMENTATION
FORMATES
GLYCINE
HYDROCARBONS
HYDROGEN
HYDROXY ACIDS
HYDROXY COMPOUNDS
INFORMATION
INHIBITION
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LACTIC ACID
LAKES
MANAGEMENT
METABOLITES
METHANE
METHANOL
METHYLAMINE
NONMETALS
NORTH AMERICA
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PROCESSING
RESPONSE MODIFYING FACTORS
SEDIMENTS
SURFACE WATERS
SYNTHESIS
TRACER TECHNIQUES
USA
WASTE MANAGEMENT
WASTE PROCESSING
WISCONSIN