Fundamental study of ethanol production from livestock increments

2005 Fiscal Year Final Research Report Summary

• Project/Area Number: 16380181
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Zootechnical science/Grassland science
• Research Institution: KYOTO PREFECTURAL UNIVERSITY
• Principal Investigator: MIYAZAKI Kohji Kyoto Prefectural University, Agriculture, Lecturer, 農学研究科, 講師 (60254322)
• Co-Investigator(Kenkyū-buntansha): USHIDA Kazunari Kyoto Prefectural University, Agriculture, Professor, 農学研究科, 教授 (50183017)
• Project Period (FY): 2004 – 2005
• Keywords: thermophile / livestock increments / ethano / hydrogen / decolorization / photosynthetic bacteria

Research Abstract

3 strains of thermophilic bacteria, which don't require yeast extract as a growth factor, were isolated newly. They produce large amount of ethanol from livestock increments. Based on the sequence of 16S rRNA gene, they were classified into the group of Clostridium, Thermoanaerobacterium, and Thermoanaerobacter, respectively. However, it was suggested that they all were newly isolated species because any ones don't have high homology with other 16S rRNA genes listed in the database. The suitable combination was determined by co-culture to increase ethanol production, and co-culture with Thermoanaerobacterium sp. and Thermoanaerobacter sp. gave the best result. Then, acetate was produced as much as ethanol. The bacteria converting acetate to hydrogen should be isolated for the effective bio-conversion system. Moreover, the color of sewage after the fermentation by thermophilic bacteria remains one of the environmental problems. Therefore, we try to isolate the bacteria converting acetate to hydrogen, and decolorizing the sewage. As the result, photosynthetic bacteria, which convert acetate to the same amount of hydrogen, and some bacteria decolorizing the sewage were isolated. This decolorizing bacteria completely diminished the color of swage caused by synthetic dye, but only 27% for the swage of livestock increments. Although more effective bacteria are needed to be isolated, if all these bacteria isolated in this study are applied to the bio-conversion system, high production of ethanol and hydrogen from livestock increments would be expected. Furthermore, the sediments after digestion contain large amount of photosynthetic bacteria. As these bacteria fix nitrogen and enrich a soil, the sediments could work as the good compost additionally.