Authors: S Vigneswari S Vijaya M I A Majid K Sudesh C S Sipaut M N M Azizan A A Amirul
Publish Date: 2009/02/03
Volume: 36, Issue: 4, Pages: 547-556
Abstract
Cupriavidus sp USMAA1020 a local isolate was able to biosynthesis poly3hydroxybutyrateco4hydroxybutyrate P3HBco4HB copolymer with various 4HB precursors as the sole carbon source Manipulation of the culture conditions such as cell concentration phosphate ratio and culture aeration significantly affected the synthesis of P3HBco4HB copolymer and 4HB composition P3HBco4HB copolymer with 4HB compositions ranging from 23 to 75 mol 4HB with various mechanical and thermal properties were successfully produced by varying the medium aeration The physical and mechanical properties of P3HBco4HB copolymers were characterized by NMR spectroscopy gelpermeation chromatography tensile test and differential scanning calorimetry The numberaverage molecular weights M n of copolymers ranged from 260 × 103 to 590 × 103Da and the polydispersities M w/M n were between 18 and 30 Increases in the 4HB composition lowered the molecular weight of these copolymers In addition the increase in 4HB composition affected the randomness of copolymer melting temperature T m glass transition temperature T g tensile strength and elongation to break Enzymatic degradation of P3HBco4HB films with an extracellular depolymerase from Ochrobactrum sp DP5 showed that the degradation rate increased proportionally with time as the 4HB fraction increased from 17 to 50 mol but were much lower with higher 4HB fraction Degradation of P3HBco4HB films with lipase from Chromobacterium viscosum exhibited highest degradation rate at 75 mol 4HB The biocompatibility of P3HBco4HB copolymers were evaluated and these copolymers have been shown to support the growth and proliferation of fibroblast cells
Keywords: