Conversion of Cellulose to Methane and Carbon Dioxide by Triculture of Acetivibrio cellulolyticus, Desulfovibrio sp., and Methanosarcina barkeri

Abstract

The fermentation of cellulose by monocultures of Acetivibrio cellulolyticus and cocultures of A. cellulolyticus-Methanosarcina barkeri, A. cellulolyticus-Desulfovibrio sp., and A. cellulolyticus-M. barkeri-Desulfovibrio sp. was studied. The monoculture produced ethanol, acetate, H2, and C02. More acetate and less ethanol was formed by the cocultures than by the monoculture. Acetate was utilized by M. barkeri in coculture with A. cellulolyticus after a lag period, whereas ethanol was metabolized by the sulfate reducer only under conditions of low H2 partial pressure, i.e., when cocultured with A. celluloyticus-M. barkeri or when grown together with the methanogen. Only the three-component culture carried out the rapid conversion of cellulose to C02 and methane. Furthermore, this culture hydrolyzed the most cellulose-85% of that initially present. This amount was increased to 90% by increasing the population of M. barkeri in the triculture. Methane production was also increased, and a quicker fermentation rate was achieved.

Fermentative degradation of acetone by an enrichment culture in membrane-separated culture devices and in cell suspensions

“…The enhancement of growth of some fermentative bacteria in the presence of acetate-utilizing methanogens has been shown previously [19][20][21], but in these cases degradation was primarily via hydrogen syntrophy, and acetate utilization enhanced the degradation rates. In the mixed culture WoAct, acetate utilization appears not to be obligately required for acetone degradation and growth, and at acetate concentrations found in 32 natural freshwater environments (0.1 to 660/xM, [22][23][24]), acetone fermentation will proceed at maximal rates.…”

Influence of Clostridium saccharolyticum on cellulose degradation by Acetivibrio cellulolyticus*

“…1979). Theoretically, cellulose degradation should be higher in mixed culture than in pure culture, as acetic acid, hydrogen and ethanol which have inhibitory effects on cellulose degradation are being constantly removed by methanogens and sulphate-reducing bacteria (Laube & Martin 1981). Since in mixed cultures.…”

The characteristics of a new non‐spore‐forming cellulolytic mesophilic anaerobe strain CM126 isolated from municipal sewage sludge

“…Total reducing sugars were determined colorimetrically with dinitrosalicylic acid reagent (Miller 1959). For the determination of cellulose a modification of the method of Laube & Martin (1981) was used. Formic acid, 8%, was used to dissolve bacterial cells and a glass fibre filter (Whatman GF/C) was used to collect the cellulose.…”