Ethylene production by the reeombinant photosynthetic bacterium from liquefied sewerage excess sludge

2001 Fiscal Year Final Research Report Summary

• Project/Area Number: 11555223
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 展開研究
• Research Field: 生物・生体工学
• Research Institution: Sojo University
• Principal Investigator: OGAWA Takahira Sojo university, Fac. of Engineering, Professor, 工学部, 教授 (40029244)
• Co-Investigator(Kenkyū-buntansha): KIDA Kennji Kumamoto University, Fac. of Engineering, Professor, 工学部, 教授 (00195306) ; MATSUOKA Masayoshi Sojo university, Fac. of Engineering, Professor, 工学部, 助教授 (10121667)
• Project Period (FY): 1999 – 2001
• Keywords: Ethylene / Rhodobacter sphaeroides / Photosynthetic bacteria / Sewage excess sludge / Ethylene-forming enzyme / Pseudomonas syringae / Rhodobacter sphaeroides

Research Abstract

The objective of this project was the production of ethylene from liquefied sewage excess sludge by the recombinant photosynthetic bacterium which harbors the ethylene-forming enzyme gene (efe) from Pseudomonas syringae. The results were summarized as follows. 1. The recombinant Rhodobacter shaeroides IFO12203 which harbors the efe gene from P. syringae was constructed by the transduction of E. coli S17 using the shuttle vector pRK415. Three promoters- lac, psbAI and the efe from P. syringae- were used. Out of them, the efe promoter only operated in the photosynthetic bacterium. This plasmid was named as pRKEFE1. 2. The maximal volume loading of the volatile suspended solid (VSS) was 140 g/liter/day (retention time 1.8 days) under high temperature conditions. We obtained 43% VSS digestibility and got 7,000 rag/liter of total organic acids (acetic acid 3,800 mg/liter and propionic acid 1,600 mg/liter) in this condition. 3. We also studied the solubilization of sewage excess sludge by the Fenton reaction. The digestibility of the excess sludge was 98% of the total MLVSS. 4. The production of ethylene from the two kinds of liquefied sewage excess sludge by the reeombinant photosynthetic bacterium was studied. The liquefied excess sludge by Fenton reaction did not produce ; ethylene, but the ethylene production from the solubilied sewage excess sludge by acid fermentation under high temperature was 50 nl/ml/hr/OD610. This value was about 42% of that of the authentic fatty acid mixture of acetic acid, propionic acid and butylic acid.