Production of (R)-chiral alcohols by a hydrogen-transfer bioreduction with NADH-dependent Leifsonia alcohol dehydrogenase (LSADH)

Gene Cloning and Expression ofLeifsoniaAlcohol Dehydrogenase (LSADH) Involved in Asymmetric Hydrogen-Transfer Bioreduction to Produce (R)-Form Chiral Alcohols

“…9) Our bioprocess is superior to the previous ones in the following points: (1) a simple reaction system because there is no need for additional NADH-regenerating system, (2) easy handling in downstream processing and low cost due to using 2-propanol as a hydrogen donor and coexisting solvent, (3) application to versatile ketones because of LSADH's broad substrate range and high enantioselectivity. 17,18) The rather low conversions observed for (R)-2-heptanol and ethyl (R)-lactate are considered to be due to the equilibrium of the reaction. For example, in the case of 2-heptanol, the K eq value of [2- Therefore, the theoretical conversion of the product was calculated to be 81% under the tested conditions from the calculation.…”

“…The combined ethyl acetate extracts were dried with Na 2 SO 4 , and analyzed by gas chromatography (GC) or high performance liquid chromatography (HPLC), as described previously. 17,18) GC was performed using a Shimadzu GC-18A system (Kyoto, Japan) equipped with a capillary column (J & W capilary column DB-1, 0:25 mm  30 m, Agilent Technologies, Palo Alto, CA) with an FID (flame ionization detector) under the following conditions: injection and detection temperature of 250 C, column temperature of 40 C for 5 min, raised to 100 C at 5 C/min, the sprit ratio was 40, and a flow rate of 1 ml/min of He. The products and substrates showed the following retention times (min): 2-heptanone, 6.3; 2-heptanol, 7.0; ethyl 3-methyl-2-oxobutanoate, 12.1; ethyl 3-methyl-2-hydroxybutanoate, 12.9.…”

“…The optimal reaction conditions observed for the free enzyme reaction (1 mM NAD þ , 10% v/v 2-propanol, pH 7.0) 18) were adopted for the E. coli biocatalyst system. As exemplified in Table 5, enantioselective reduction of the ketones and keto esters by this process using LSADH with 2-propanol as a hydrogen donor gave chiral alcohols with an enantiomeric purity of > 99% e.e.…”

“…strain S749, and have characterized it in detail. 17,18) LSADH is a NAD þ -dependent ADH, and it produces many chiral alcohols from ketones, and -keto and -ketoesters with high enantioselectivity. This process can function without the additional coenzyme regeneration system in the presence of 2-propanol in a similar manner to PAR (Fig.…”

Production of (R)‐1‐phenylethanols through bioreduction of acetophenones by a new fungus isolate Trichothecium roseum

“…[1][2][3][4][5] For example, enantiopure (R)-1-phenylethanol (2a) is an important chiral building block for pharmaceuticals, agrochemicals, and natural products. [6][7][8][9][10] For economic and environmental reasons, biocatalysis has recently gained increasing importance for the preparation of enantiopure alcohols from prochiral ketones. For this purpose, ketoreductases have been shown to be unique biocatalysts in the preparation of enantiopure alcohols from prochiral ketones.…”