A green method for polybutylene succinate recycling: Depolymerization catalyzed by lipase B from Candida antarctica during reactive extrusion

摘要

This study aims to investigate a "green" recycling route for polybutylene succinate (PBS) based on reactive extrusion in the presence of an enzyme catalyzing the hydrolysis of this aliphatic polyester: lipase B from Candida antarctica. This enzyme was chosen due to its thermal stability, since reactive extrusion was performed at 120 degrees C (i.e. above PBS melting temperature). PBS hydrolysis was measured after extrusion at 120 degrees C either in a single or a twin screw extruder, in the presence of 0-10 wt% C. antarctica lipase for 5 or 30 min. In a twin screw extruder, the residual activity of the enzyme was still 38% or 24%, after 5-30 min extrusion at 120 degrees C, respectively. For instance, the weight average molecular weight (M-w) of PBS decreased from 82,000 to 4500 g mol(-1) after extrusion for 5 min in the presence of 1% wt of lipase. The highest yield of free succinic acid release (44%) was obtained following a 30 min extrusion in the presence of 10 wt% of C. antarctica lipase. The drastic decrease in weight average molecular weight of PBS after enzymatic hydrolysis caused an only 10 degrees C decrease in the melting temperature. (C) 2015 Elsevier Ltd. All rights reserved.