Preparation of Chiral Hydroxy Esters Using Actinobacteria: Biocatalyst Activity of Marine-Derived Micromonospora and Streptomyces Strains

• Published in: Open journal of applied sciences (Irvine, CA) CA), 2013-03, Vol.3 (1), p.116-122
• Main Authors: Ishihara, Kohji, Fujita, Aiko, Sakiyama, Akane, Kobayashi, Yuko, Hori, Kaoru, Maruike, Kanako, Masuoka, Noriyoshi, Nakajima, Nobuyoshi, Hamada, Hiroki
• Format: Article
• Language: English
• Subjects: Actinobacteria; Micromonospora; Streptomyces
• ISSN: 2165-3917; 2165-3925
• DOI: 10.4236/ojapps.2013.31017

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 alpha -keto esters using these 4 actinomycetes was tested. As a result, it was found that these strains had a reducing activity toward various alpha -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 alpha -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.