Author(s)

Kohji Ishihara, Aiko Fujita, Akane Sakiyama, Yuko Kobayashi, Kaoru Hori, Kanako Maruike, Noriyoshi Masuoka, Nobuyoshi Nakajima, Hiroki Hamada

Department of Life Science, Okayama University of Science, Okayama, Japan.
Graduate School of Health and Welfare, Okayama Prefectural University, Soja, Japan.

To research the potential ability of marine-derived actinomycetes to act as biocatalysts, 8 Micromonospora strains and 5 Streptomyces strains were screened. Two recommended media (227 and 1076 media) and 2 modified media (1076-25% and P-1076-25% media) for liquid culture of these marine-derived actinomycetes were tested. As a result, 2 Micromonospora strains (Micromonospora sp. NBRC107096 and 107097) cultured with the 1076-25% medium and 2 Streptomyces strains (Streptomyces tateyamensis NBRC105048 and Streptomyces sp. NBRC105896) cultured with P-1076-25% medium showed a good growth. The stereoselective reduction of α-keto esters using these 4 actinomycetes was tested. As a result, it was found that these strains had a reducing activity toward various α-keto esters. The introduction of L-glutamate or sucrose as an additive remarkably increased the conversion ratios in the reduction of substrates by the Micromonospora strain. Furthermore, in the presence of L-alanine, Streptomyces tateyamensis NBRC105048 reduced ethyl pyruvate, ethyl 2-oxobutanoate, ethyl 2-oxopentanoate, ethyl 2-oxohexanoate, and ethyl 3-methyl-2-oxobutyrate to the corresponding α-hydroxy ester with a high conversion ratio and with excellent enantiomeric excess. Thus, we found that these marine-derived actinomycetes have great potential to be used as biocatalysts for stereoselective reduction of carbonyl compounds.

Marine Bacteria; Micromonospora; Streptomyces; Biocatalyst; Chiral Alcohol

K. Ishihara, A. Fujita, A. Sakiyama, Y. Kobayashi, K. Hori, K. Maruike, N. Masuoka, N. Nakajima and H. Hamada, "Preparation of Chiral Hydroxy Esters Using Actinobacteria: Biocatalyst Activity of Marine-Derived Micromonospora and Streptomyces Strains," Open Journal of Applied Sciences, Vol. 3 No. 1, 2013, pp. 116-122. doi: 10.4236/ojapps.2013.31017.