Degradation of poly(butylene succinate) and poly(butylene succinate-co-butylene adipate) by a lipase from yeast Cryptococcus sp grown on agro-industrial residues

The yeast, Cryptococcus sp. MTCC 5455 was grown on various agro-industrial residues for the production of lipase. A maximum lipase activity of 753 +/- 19 U g dry substrate(-1) (U gds(-1)) and a biomass of 103 +/- 5 mg gds(-1) was obtained at 25 degrees C and 120 h using cottonseed oil cake with 71% moisture content and 30% (v/w) inoculum. The recovery of the enzyme was increased by 14.1%, when the fermented substrate was extracted in 2 mM CaCl2 center dot 2H(2)O solution. The crude enzyme partially purified by (NH4)(2)SO4 precipitation showed a major 22 kDa protein on SDS-PAGE. The enzyme has good potential for hydrolysis of poly(butylene succinate) (PBS) and poly(butylene succinate-co-butylene adipate) (PBSA) and complete degradation of the polymeric films were observed at 72 h and 16 h respectively. The degradation was evaluated by Fourier transform infrared (FTIR) and H-1 NMR spectroscopy. The complete hydrolysis of polymers by Cryptococcus sp. lipase makes the process ideal and also serves as a baseline for its exploitation in polymer degradation. (C) 2016 Elsevier Ltd. All rights reserved.