Performance comparison of commercial and home-made lipases for synthesis of poly(δ-valerolactone) homopolymers

Novozyme 435, which is the commercially available immobilized form of Candida antarctica lipase B, has been successfully conducted ring opening polymerization of lactones in organic solvents. In this paper, it was aimed to introduce an alternative biocatalyst for Novozyme 435. Candida antarctica lipase B immobilized onto rice husk ashes via physical adsorption (with a specific activity of 4.4 U/mg) was prepared in previous studies and used as a biocatalyst for poly(δ-valerolactone) synthesis in the present work. Polymerization reactions were proceeded at various reaction temperatures and periods via both two immobilized enzyme preparations. The resulting products were characterized spectroscopically and thermally. The highest molecular weight (M_n = 9010 g/mol) was obtained via Novozyme 435 catalysis at 40℃ and 24 hours. The performance of home-made lipase, which resulted in a molecular weight of 8040 g/mol, was close to commercial one.