An enzyme cascade synthesis of ε-caprolactone and its oligomers

• Published in: Angewandte Chemie International Edition
• Main Authors: Schmidt, Sandy, Scherkus, Christian, Muschiol, Jan, Menyes, Ulf, Winkler, Till, Hummel, Werner, Gröger, Harald, Liese, Andreas, Herz, Hans Georg, Bornscheuer, Uwe Theo
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley-VCH 2015
• Subjects: Baeyer-Villiger monooxygenases; Cascade reactions; Enzyme catalysis; Polymer synthesis; ε-caprolactone; 540: Chemie; 600: Technik; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/11420/10104

Poly-ε-caprolactone (PCL) is chemically produced on an industrial scale in spite of the need for hazardous peracetic acid as an oxidation reagent. Although Baeyer-Villiger monooxygenases (BVMO) in principle enable the enzymatic synthesis of ε-caprolactone (ε-CL) directly from cyclohexanone with molecular oxygen, current systems suffer from low productivity and are subject to substrate and product inhibition. The major limitations for such a biocatalytic route to produce this bulk chemical were overcome by combining an alcohol dehydrogenase with a BVMO to enable the efficient oxidation of cyclohexanol to ε-CL. Key to success was a subsequent direct ring-opening oligomerization of in situ formed ε-CL in the aqueous phase by using lipase A from Candida antarctica, thus efficiently solving the product inhibition problem and leading to the formation of oligo-ε-CL at more than 20 g L-1 when starting from 200 mM cyclohexanol. This oligomer is easily chemically polymerized to PCL.