Propionic acid metabolism and poly-3-hydroxybutyrate-co-3-hydroxyvalerate production by a prpC mutant of Herbaspirillum seropedicae Z69

Publication date: Available online 18 September 2018Source: Journal of BiotechnologyAuthor(s): Ana Inés Catalán, Ana Karen Malan, Fernando Ferreira, Paul R. Gill, Silvia BatistaAbstractPolyhydroxyalkanoates (PHAs) are thermoplastic polyesters produced by a wide range of bacteria as carbon and energy reserves. PHA accumulation is typically increased under unbalanced growth conditions and with carbon source in excess. Although polyhydroxybutyrate (PHB) could be used for specific applications, it is brittle and not a useful alternative for plastics like polypropylene. Far more useful polypropylene-like PHAs, are copolymers composed of 3-hydroxybutyrate and 3-hydroxyvalerate, P(3HB-co-3 HV). Propionic acid is one of the carbon sources that can be used to generate 3 HV A mutant derived from Herbaspirillum seropedicae Z69, a strain previously described as capable of producing P(3HB-co-3 HV) from propionic acid, was constructed to increase 3 HV biosynthetic efficiency. The strategy involved elimination of a catabolic route for propionyl-CoA by deficiency marker exchange of a selected gene. The mutant (Z69Prp) was constructed by elimination of the 2-methylcitrate synthase (PrpC) gene of the 2-methylcitrate cycle for propionate catabolism. Strain Z69Prp was unable to grow on sodium propionate, but in cultures with glucose-propionate accumulated 50% of its dry weight as copolymer. Z69Prp had 14.1 mol% 3 HV; greater than that of strain Z69 (2.89 mol%). The 3 HV yield...
Source: Journal of Biotechnology - Category: Biotechnology Source Type: research