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Asymmetric reduction of prochiral ketones by cell‐free systems from alcaligenes eutrophus
Author(s) -
Madyastha Kattigere M.,
Gururaja Tarikere L.
Publication year - 1994
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.280590307
Subject(s) - nerolidol , chemistry , epoxide , double bond , stereochemistry , sesquiterpene , acetaldehyde , fermentation , diol , periodate , terpene , organic chemistry , alcohol , ethanol , catalysis , chromatography , linalool , essential oil
A strain of Alcaligenes eutrophus has been isolated from the soil by enrichment culture technique with nerolidol ( 1 ), a sesquiterpene alcohol, as the sole source of carbon and energy. Fermentation of nerolidol ( 1 ) by this bacterium in a mineral salts medium resulted in the formation of two major metabolites, viz. geranylacetone ( 2 ) and an optically active alcohol, ( S )‐(+)‐geranylacetol ( 3 ). Nerolidol ( 1 )‐induced cells readily transformed 1,2‐epoxynerolidol ( 4 ) and 1,2‐dihydroxynerolidol ( 5 ) into geranylacetone ( 2 ). These cells also exhibited their ability to carry out stereospecific reduction of 2 into ( S )‐(+)‐geranylacetol ( 3 ). Oxygen uptake studies clearly indicated that nerolidol‐induced cells oxidized compounds 2, 3, 4, 5 and ethyleneglycol ( 7 ). Based on the nature of the metabolites isolated, the ability of nerolidol‐induced cells to convert compounds 4 and 5 into geranylacetone ( 2 ), and oxygen uptake studies, a pathway for the microbial degradation of nerolidol ( 1 ) has been proposed. The proposed pathway envisages the epoxidation of the terminal double bond, opening of the epoxide and cleavage between C‐2 and C‐3 in a manner similar to the periodate oxidation of cis ‐diol. The cell‐free extract prepared from nerolidol‐induced cells readily carried out the asymmetric reduction of compound 2 to an optically active alcohol ( 3 ) in the presence of NAD(P)H. The cell‐free extract carried out both oxidation and reduction reactions at two different pH values and exhibited wide substrate specificity towards various steroids besides terpenes.