Polyhydroxyalkanoates (PHAs) are microbial polyesters attracting great interest while further functionalisation could widen their applicability. Various E coli based production systems using the PHA biosynthetic operon from Bacillus cereus 6E/2, were designed to enhance the accumulation of PHAs with high mcl moieties. Media optimization and system engineering were applied, yielding to the production of up to 260 mg/L of PHAs. Polymers characterization revealed a low grade of crystallinity and remarkable hydrophobic features. For further functionalization, a novel enzyme based strategy was developed. Lipase B from Candida antarctica (CaLB) was used to catalyze the terminal coupling of PHA with: i) dimethyl itaconate (DMI) in order to introduce reactive side chain vinyl moieties for easy coupling of functional molecules and/or ii) biocompatible polyethylene glycol (PEG) to tune polymer hydrophilicity. The functionalized DMI-PHA, PEG-PHA and PEG-DMI-PHA polymers obtained and characterised by NMR, GPC, FT-IR, and WCA in this study open new perspectives for the use of PHAs as biodegradable and biocompatible materials of choice for biomedical applications.
Enzymatic production of clickable and PEGylated recombinant polyhydroxyalkanoates
Immirzi B;Dal Poggetto G;
2017
Abstract
Polyhydroxyalkanoates (PHAs) are microbial polyesters attracting great interest while further functionalisation could widen their applicability. Various E coli based production systems using the PHA biosynthetic operon from Bacillus cereus 6E/2, were designed to enhance the accumulation of PHAs with high mcl moieties. Media optimization and system engineering were applied, yielding to the production of up to 260 mg/L of PHAs. Polymers characterization revealed a low grade of crystallinity and remarkable hydrophobic features. For further functionalization, a novel enzyme based strategy was developed. Lipase B from Candida antarctica (CaLB) was used to catalyze the terminal coupling of PHA with: i) dimethyl itaconate (DMI) in order to introduce reactive side chain vinyl moieties for easy coupling of functional molecules and/or ii) biocompatible polyethylene glycol (PEG) to tune polymer hydrophilicity. The functionalized DMI-PHA, PEG-PHA and PEG-DMI-PHA polymers obtained and characterised by NMR, GPC, FT-IR, and WCA in this study open new perspectives for the use of PHAs as biodegradable and biocompatible materials of choice for biomedical applications.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
