| Co-Investigator(Kenkyū-buntansha) |
OHTA Masaya Fukuyama University, Department of Biotechnology, Associate Professor, 生命工学部, 助教授 (00203802)
IKEGUCHI Yoko Fukuyama University, Department of Biotechnology, Assistant, 生命工学部, 助手 (70389071)
TAMAI Masahiro Western Hiroshima Prefecture Industrial Research Institute, Resources & Environment Technology, Chief Researcher, 主任研究員
TAMURA Yukiyoshi Maruzen Pharmaceuticals co., Ltd., Biological & Chemical Research Dept., Section Manager, 研究開発本部, グループリーダー
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2005: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Research Abstract |
105 yeast strains which produced glycolipid biosurfactants(BS) from soybean oil as a sole carbon source, were selected from natural environments. These yeast strains were classified into 6 groups based on the type of glycolipids BS produced. Among them, 43 yeast strains were found to accumulate two novle glycolipids in addition to mannosylerythritol lipids(MEL-A, -B, -C and D). The new glycolipids were isolated from culture of a yeast strain TM-606, identified as a Pseudozyma aphidis, and their structures were characterized to be 4,6-di-O-acetyl-2,3-di-O-alkanoyl-β-D-mannopyranosyl-(1-6)-O-meso-mannitol(MML-A) and 4-mono-O-acetyl-2,3-di-O-aikanoyl-β-D-mannopyranosyl-(1-6)-O-meso-mannitol(MML-C). Both MMLs lowered the surface tension of water to 32-34 dyne/cm at critical micelle concentration of 1.3-2.8 x 10^<-5> M. Mixture of MEL and MML, has several biological activities, such as antimicrobial activity, repression of platelet agglutination, mineralization of osteoblast, melanogenesis. We also found several yeast strains producing new type of MEL and NML in which C_<18>-fatty acids were linked at C-1 of erythritol and mannitol, respectively.
We developed a convenient fractionation method of the mixture MEL-A,-B,-C, and MML-A and -C by MPLC and a method for the separation of individual BS into molecular species by HPLC. The interface activities were found to be influenced by chain length and the degree of unsaturation of the constituent fatty acids.
MEL productivity of several yeast strains were examined by using several vegetable oils. The yeast strain TM-181, identified as a Pseudozyma tsukubaensis, cultured with linceed oil gave the highest productivity of MEL. This yeast produced MEL of 41.3 g/L/day under the optimum culture condition.
It was found that fatty acids in the glycolipids were β-oxidation intermediates of fatty acid in vegetable oils used.
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