Camelina Oil as a Promising Substrate for mcl-PHA Production in Pseudomonas sp. Cultures

Abstract

Background and objective: Polyhydroxyalkanoates are biodegradable polyesters synthesized by some prokaryotic organisms from renewable sources. Medium-chain-length Polyhydroxyalkanoates show interesting properties as elastic and adhesive specialty polymers. Medium-chain-length Polyhydroxyalkanoates producers such as Pseudomonas sp. have demonstrated high yields on fats and oils. Camelina sativa is non-food chain competing crop, whose seed contain about 43% (w w -1 ) oil in dry matter with about 90% (w w -1 ) of unsaturated fatty acids. Camelina oil was for the first time tested for the production of medium-chainlength Polyhydroxyalkanoates by different Pseudomonas strains. Material and methods: The production of Polyhydroxyalkanoate was evaluated in a nitrogen-limited minimal medium supplemented with crude Camelina oil or saponified oil to compare the production capability of Pseudomonas sp. strains. A phosphates-limited medium was used to optimize polyhydroxyalkanoate production in fed-batch assays. Experiments were carried out by duplicates. Results and conclusion: Pseudomonas resinovorans was used for direct fermentation of Camelina oil without prior hydrolysis. A first approach to process development in bioreactor has provided up to 40% (w w -1 ) polymer content, matching highest medium-chain-length polyhydroxyalkanoates titer reported from plant oils (13.2 g l -1 ). Camelina oil was shown to be a suitable substrate for production of medium-chain-length polyhydroxyalkanoates. This non-food vegetable oil gave good results for Pseudomonas resinovorans DSM 21078 without any pre-treatment. Conflict of interest : The authors declare no conflict of interest.