GROWTH PATTERNS AND HYDROGEN SULFIDE PRODUCTION BY MIXED CULTURES IN A CELLULOSE-BASED MICROCOSM

Abstract

Studies of the trophic relationships in microbial reduction of sulfate established the need for three physiological types of organisms: cellulose- digesters (Cellulomonas, Cytophaga or Micromonospora), a lactic acid fermenter (Enterobacter), and a sulfate reducer (Desulfovibrio). Microcosms based on cellulose mineral salts medium were inoculated with varying combinations of mixed cultures and incubated at 30°C for 18 days. The extent of sulfate reduction varied in the microcosms. A 5- member culture which contained the three cellulolytic organisms reduced the most sulfate (52%). Cellulomonas was the most efficient cellulolytic partner. Unless all three physiological types were present, sulfate was not reduced.