In 1991, the dominant growth-bacteria were isolated from the aerobic night soil digestion tanks at Inachuo Sanitation Center, and 98% of them was found to be Bacillus sp. Their biochemical characteristics had been reported.In 1993, the treatment-ability of this facility was improved, and the dominant growth-bacteria and their biochemical characteristics were reinvestigated.The number of bacteria was up to 1×109cells/ml at the 1st tank, and 66% of them was accounted for Bacillus sp., 14% for Nocardioform bacteria, 14% for gram-positive bacteria, 2% for cocci, 3% for gram-negative bacteria, and 3% for Clostridium sp. Additionally, yeast (0.1%) was isolated. This time, Bacillus sp. (φ<0.5μm), gram-positive bacteria and Clostridium sp. were newly isolated, and the number of Nocardioform bacteria increased. Bacillus sp. and Nocardioform bacteria participated in hydrolysis of starch, while only Bacillus sp. hydrolyzed cookedmeat. In assimilation of soybean oil the participants were Bacillus sp., Nocardioform bacteria and cocci. Bacillus sp., and Nocardioform bacteria decomposed malodor components.
