title: Biosynthesis and thermal properties of PHBV produced from levulinic acid by Ralstonia eutropha.
abstract: Levulinic acid (LA) can be cost-effectively produced from a vast array of renewable carbohydrate-containing biomaterials. LA could facilitate the commercialization of the polymer poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and PHBV-based products as carbon substrates. Therefore, this paper focused on the production of PHBV by Ralstonia eutropha with LA for hydroxyvalerate (HV) production, which plays an important role in enhancing the thermal properties of PHBV. Accordingly, the HV content of PHBV varied from 0-40.9% at different concentrations of LA. Stimulation of cell growth and PHBV accumulation were observed when 2-6 g L(-1) LA was supplied to the culture. The optimal nitrogen sources were determined to be 0.5 g L(-1) ammonium chloride and 2 g L(-1) casein peptone. It was determined that the optimal pH for cell growth and PHBV accumulation was 7.0. When the cultivation was performed in large scale (2 L fermenter) with a low DO concentration of 30% and a pH of 7.0, a high maximum dry cell weight of 15.53 g L(-1) with a PHBV concentration of 12.61 g L(-1) (53.9% HV), up to 81.2% of the dry cell weight, was obtained. The melting point of PHBV found to be decreased as the fraction of HV present in the polymer increased, which resulted in an improvement in the ductility and flexibility of the polymer. The results of this study will improve the understanding of the PHBV accumulation and production by R. eutropha and will be valuable for the industrial production of biosynthesized polymers.
authors.affiliation: Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, and The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, China.
authors.forename: Yuanpeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Ronghui
authors.initials: R
authors.lastname: Chen
authors.forename: JiYuan
authors.initials: J
authors.lastname: Cai
authors.forename: Zhenggui
authors.initials: Z
authors.lastname: Liu
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Zheng
authors.forename: Haitao
authors.initials: H
authors.lastname: Wang
authors.forename: Qingbiao
authors.initials: Q
authors.lastname: Li
authors.forename: Ning
authors.initials: N
authors.lastname: He
mesh_terms: D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D020118:Cupriavidus necator / Q000254:growth & development / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D007982:Levulinic Acids / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism; D011091:Polyesters / Q000737:chemistry* / Q000378:metabolism*; D013816:Thermodynamics; D000094122:Polyhydroxybutyrates
chemical_list: D002244:Carbon; D005947:Glucose; D007982:Levulinic Acids; D009584:Nitrogen; D011091:Polyesters; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates; C032246:levulinic acid