Accumulation of Biodegradable Copolyesters of 3-Hydroxy-Butyrate and 3-Hydroxyvalerate in Alcaligenes eutrophus

摘要

Biodegradable copolyesters of 3-hydroxybutyrate-co-3-hydroxyvaler-ate (3HB-3HV) were produced by Alcaligenes eutrophus in a two-staged process, namely growth stage and nitrogen-deficient polyester-accumulation stage. When C_5 was used as the sole carbon source, the copolyester contained 43 mol % of 3HV. A range of copolyesters with 0-43 mol % of 3HV could be produced by using a medium containing different concentration ratios of butyric acid C_4 and C_5. T_m of PHB homopolymer was 177.6°C and that of copolyester with highest 3HV mol fraction of 43% was 99.0°C. C_5 concentration in the medium could be an effective means to control the polymeric composition and mechanical properties of the copolyesters accumulated in A. eutrophus.