Pulsed Feeding Strategy is More Favorable to Medium-Chain-Length Polyhydroxyalkanoates Production from Waste Rapeseed Oil

This article presents the results of production and characterization of medium-chain-length polyhydroxyalkanoates (mcl-PHAs) using Pseudomonas sp. Gl01. Studies have been carried out to find suitable feeding strategies for mcl-PHAs production and, for the first time, to investigate in-depth the properties of biopolyesters obtained under controlled conditions with waste rapeseed oil as a substrate. Up to 44% mcl-PHAs of cell dry weight was produced at 41 h of biofermentor culture by employing pulsed feeding of waste rapeseed oil. GC analysis showed a polymer composition with monomer length of C-6 to C-12 with C-8 and C-10 as the principal monomers. The monomeric structure of the extracted polyesters did not depend on the cultivation time and the feeding strategy. Molecular weight of the mcl-PHAs was found to be ranging from 57 to 154 kDa. Thermal analyses showed the obtained mcl-polyhydroxyalkanaotes to be semi-crystalline biopolymer with promising thermal stability, having a glass transition temperature of -38 to -50 degrees C. (C) 2014 American Institute of Chemical Engineers