TITLE:
The Ability of Edible Mushrooms to Act as Biocatalysts: Preparation of Chiral Alcohols Using Basidiomycete Strains
AUTHORS:
Kohji Ishihara, Yukiko Nishikawa, Mari Kaneko, Anna Kinoshita, Nozomi Kumazawa, Daichi Kobashigawa, Kohei Kuroda, Masashi Osawa, Tatsunori Yamamoto, Nobuyoshi Nakajima, Hiroki Hamada, Noriyoshi Masuoka
KEYWORDS:
Basidiomycete; Edible Mushroom; Biocatalyst; Chiral Alcohol
JOURNAL NAME:
Advances in Microbiology,
Vol.2 No.2,
June
13,
2012
ABSTRACT: To examine the potential ability of edible mushrooms to act as biocatalysts, 19 basidiomycete strains were screened. Modified media (PG, O, and PGO medium) for liquid cultivation of these basidiomycete strains were designed and tested. Wet cells (>10 g) of 4 basidiomycete strains (Pleurotus salmoneostramineus H7, P. salmoneostramineus H13, Ganoderma lucidum NBRC31863, Flammulina velutipes NBRC31862) were harvested from PGO medium for 7 days. The stereoselective reduction of α-keto esters using the 4 strains was tested. It was found that each of these strains had a reducing activity toward 6 aliphatic α-keto esters. In the presence of L-alanine as an additive, the reduction of ethyl 2-oxobutanoate and ethyl 2-oxopentanoete by P. salmoneostramineus H7 produced the corresponding alcohol with a high conversion ratio and with excellent enantiomeric excess (>99% e.e. (R)). Furthermore, ethyl pyruvate, ethyl 2-oxobutanoate, and ethyl 2-oxopentanoate were predominantly reduced to the corresponding (R)-hydroxy ester (>99% e.e.) by G. lucidum. Thus, we found that these edible mushrooms have great potential to be used as biocatalysts for the stereoselective reduction of carbonyl compounds.