Adaptation of mesophilic anaerobic sewage fermentor populations to thermophilic temperatures
Thermophilic (50/sup 0/ ) and obligately thermophilic (60/sup 0/C) anaerobic carbohydrate- and protein-digesting and methanogenic bacterial populations were enumerated in a mesophilic (35/sup 0/C) fermentor anaerobically digesting municipal primary sludge. Of the total population in the mesophilic fermentor, 9% were thermophiles and 1% were obligate thermophiles. Of these 10%, the percentages of bacteria (thermophiles and obligate thermophiles, respectively) able to use specific substrates were as follows: bacteria able to digest albumin, casein, starch, and mono- and disaccharides, 30 and 10%; pectin degraders, 10 and 0.2%; cellulose degraders, 2 and 0.06%; methanogens that grow with H/sub 2/ and CO/sub 2/, methanol, and dimethylamine, 9 and 1%; methanogens that grow with formate, 8 and 5%; and methanogens that grow with acetate, 25 and less than 0.8%. Shortly after the temperature was elevated from 35 to 50 or 60 degrees C, the digestion of albumin, casein, starch, and mono- and disaccharides was detected, and methane was produced from H/sub 2/ and CO/sub 2/. Methane produced from acetate was not delayed at 50 degrees C, but was delayed by 29 days at 60 degrees C. Methane produced from formate was delayed by 3 days, from methanol by 7 days, and from dimethylamine by 5 days at 50 and 60 degrees C. A 10- and 20-day acclimation period was required for hydrolysis of pectin and cellulose, respectively, at 50 degrees C. Digestion of pectin required 20 days and cellulose longer than 85 days when the temperature was elevated abruptly from 35 to 60 degrees C. The acclimation period for the digestion of pectin and cellulose at 60 degrees C was shortened to 3 and 15 days, respectively, by seeding with a small amount of a culture acclimated to 50 degrees C. The data suggest that enrichment of cellulolytic, pectinolytic, and acetate-utilizing bacteria is crucial for the digestion of sewage sludge at 60 degrees C. (Refs. 17).
- Research Organization:
- Center for Laboratories and Research, New York State Dept. of Health, Albany, NY 12201
- OSTI ID:
- 5193352
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 45:4; ISSN AEMID
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
ALKANES
ANAEROBIC DIGESTION
BACTERIA
BIOCHEMICAL REACTION KINETICS
BIOCONVERSION
BIOLOGICAL ADAPTATION
DIGESTION
HYDROCARBONS
KINETICS
MANAGEMENT
MESOPHILIC CONDITIONS
METHANE
METHANOGENIC BACTERIA
MICROORGANISMS
ORGANIC COMPOUNDS
PROCESSING
PRODUCTION
REACTION KINETICS
SEWAGE
SEWAGE SLUDGE
SLUDGES
THERMOPHILIC CONDITIONS
WASTE MANAGEMENT
WASTE PROCESSING
WASTES