- 生物工学会誌 : seibutsu-kogaku kaishi
- vol.79, no.12, 2001-12-15
To establish an efficient method for the microbial treatment of kitchen refuse, experiments were performed to isolate heat-stable multi-enzyme-producing thermophilic bacteria and to verify functional activities of the isolates for the complete decomposition of kitchen refuse. Five Bacillus strains-B.amyloliquefaciens FTP148, B.amyloliquefaciens FTP2414, B.subtilis FTP237, B.Licheniformis FTP136, and B.licheniformis FTP2530-were successfully isolated from feces of the Giant Panda. The strains showed efficient growth at incubation temperatures between 45℃ and 60℃ and produced amylase, protease, and lipase. The highest activities of the amylase and protease produced by the strains at the optimal growth temperature were obtained at reaction temperatures between 50℃ and 60℃. The amylase and protease activities were stable up to maximum temperatures of 75℃ and 70℃, respectively; after incubation at 60℃ for 3 h, 59% and 40%, respectively, of the initial activity remained. Using a commercial waste-treatment device, kitchen refuse was treated with the five strains with the following results. When 1 kg per day was treated for 4 weeks, a total of 24 kg of mixed refuse consisting of green vegetables and fish remains as well as raw and/or fried potatoes was reduced to only 0.98 kg and a final digestive rate of 96% was obtained. It is noteworthy that the internal temperature of the compost mass reached a peak of 72℃. These results indicate that the novel thermophilic bacterial strains isolated from Giant Panda feces may be useful for high-performance waste treatment at a high temperature of 65℃.