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Item type:Publication, Access status: without files , A chemo-enzymatic route to synthesize (S)-γ-valerolactone from levulinic acid(Springer, 2013-01-08); ; ; Levulinic acid is a feasible platform chemical derived from acid-catalyzed hydrolysis of lignocellulose. The conversion of this substrate to (S)-γ- valerolactone ((S)-GVL) was investigated in a chemo-enzymatic reaction sequence that benefits from mild reaction conditions and excellent enantiomeric excess of the desired (S)-GVL. For that purpose, levulinic acid was chemically esterified over the ion exchange resin Amberlyst 15 to yield ethyl levulinate (LaOEt). The keto ester was successfully reduced by (S)-specific carbonyl reductase from Candida parapsilosis (CPCR2) in a substrate-coupled cofactor regeneration system utilizing isopropanol as cosubstrate. In classical batch experiments, a maximum conversion of 95% was achieved using a 20-fold excess of isopropanol. Continuous reduction of LaOEt was carried out for 24 h, and a productivity of more than 5 mg (S)-ethyl-4-hydroxypentanoate (4HPOEt) per μg CPCR2 was achieved. Afterwards (S )-4HPOEt (>99%ee) was substituted to lipase-catalyzed lactonization using immobilized lipase B from Candida antarctica to yield (S)-GVL in 90% overall yield and >99% ee.Publicationtype: Journal ArticleScopus© Citations 32 104