Ecophysiological adaptations of anaerobic bacteria to low pH: analysis of anaerobic digestion in acidic bog sediments. [Lactobacillus; Clostridium; Sarcina ventriculi]
The dynamics of anaerobic digestion were examined in the low-pH sediments of Crystal Bog in Wisconsin. The sediments (pH 4.9) contained 71% organic matter and the following concentrations of dissolved gases (micromoles per liter):CO/sub 2/, 1140; CH/sub 4/, 490; and H/sub 2/, 0.01. The rate of methane production was 6.2 ..mu..mol/liter of sediment per h, which is slower than eutrophic, neutral sediments. Microbial metabolic processes displayed the following pH optima: hydrolysis reactions, between 4.2 and 5.6; aceticlastic methanogenesis, 5.2; and hydrogen-consuming reactions, 5.6. The turnover rate constants for key intermediary metabolites were (h/sup -1/): glucose, 1.10; lactate, 0.277; acetate, 0.118; and ethanol, 0.089. The populations of anaerobes were low, with hydrolytic groups (10/sup 6//ml) several orders of magnitude higher than methanogens (10/sup 2//ml). The addition of carbon electron donors to the sediment resulted in the accumulation of hydrogen, whereas the addition of hydrogen resulted in the accumulation of fatty acids and the inhibition of hydrogen-producing acetogenic reactions. Strains of Lactobacillus, Clostridium, and Sarcina ventriculi were isolated from the bog, and their physiological attributes were characterized in relation to hydrolytic process functions in the sediments. The present studies provide evidence that the pH present in the bog sediments alter anaerobic digestion processes s, that total biocatalytic activity is lower bu the general carbon and electron flow pathways are similar to those of neutral anoxic sediments.
- Research Organization:
- Univ. of Wisconsin, Madison
- OSTI ID:
- 6791685
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 53:1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
ACIDIFICATION
BIOLOGICAL ADAPTATION
ANAEROBIC DIGESTION
BIOCHEMICAL REACTION KINETICS
BACTERIA
PHYSIOLOGY
BIOSYNTHESIS
CLOSTRIDIUM
ECOLOGY
LACTOBACILLUS
METABOLISM
METHANE
SEDIMENTS
WETLANDS
ALKANES
AQUATIC ECOSYSTEMS
BIOCONVERSION
DIGESTION
ECOSYSTEMS
HYDROCARBONS
KINETICS
MANAGEMENT
MICROORGANISMS
ORGANIC COMPOUNDS
PROCESSING
REACTION KINETICS
SYNTHESIS
WASTE MANAGEMENT
WASTE PROCESSING
550700* - Microbiology
550500 - Metabolism
520200 - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)