Production of copolyesters of 3-hydroxybutyrate and 3-hydroxyvalerate by Alcaligenes eutrophus from butyric and pentanoic acids

Summary Copolyesters of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) have been produced by Alcaligenes eutrophus in nitrogenfree culture solutions of butyric and pentanoic acids. When pentanoic acid was used as the sole carbon source, a copolyester with an unusually high 3HV fraction of 90 mol% was produced. Copolyesters with a wide range of compositions (0–90 mol% 3HV) were obtained by using butyric and pentanoic acids together as carbon sources. The biosynthetic pathways of poly(3-hydroxybutyrate) were investigated using 1-¹³C]acetate and 1-¹³C]butyrate. It is suggested that butyric and pentanoic acids are incorporated into the copolyester as 3HB and 3HV units respectively without decomposition of the carbon skeletons in the cell.