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In situ product removal using a crystallization loop in asymmetric reduction of 4‐oxoisophorone by Saccharomyces cerevisiae
Author(s) -
BuqueTaboada Evelyn M.,
Straathof Adrie J.J.,
Heijnen Joseph J.,
van der Wielen Luuk A.M.
Publication year - 2004
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.20093
Subject(s) - crystallization , fermentation , biocatalysis , yeast , chemistry , product inhibition , chemical engineering , saccharomyces cerevisiae , final product , by product , catalysis , organic chemistry , reaction mechanism , biochemistry , enzyme , economics , market economy , non competitive inhibition , engineering
In situ product crystallization was investigated for solid product crystals that were obtained during fermentation. The model reaction was the asymmetric reduction of 4‐oxoisophorone (OIP) using baker's yeast ( S. cerevisiae ) as a biocatalyst. The target product was 6 R ‐dihydro‐oxoisophorone (DOIP), also known as levodione, a key intermediate in carotenoid synthesis. DOIP was degraded by baker's yeast mainly to (4 S ,6 R )‐actinol, an unwanted byproduct in the process. Actinol formation reached up to 12.5% of the initial amount of OIP in the reactor during a batch process. However, better results were obtained when the dissolved DOIP concentration was controlled using an integrated fermentation–crystallization process because: (a) actinol formation was reduced to 4%; and (b) DOIP crystal formation in the reactor was avoided. DOIP productivity was improved by 50% and its selectivity was raised from 87% to 96% relative to the batch process. In the integrated process, most of the product was recovered as pure crystals; this may already minimize, if not eliminate, the need for organic solvents in the final purification steps. An almost sixfold reduction in biocatalyst consumption per kilogram product was achieved, which also can contribute to the minimization of waste streams. © 2004 Wiley Periodicals, Inc.