Mitomo H, Takahashi T, Ito H, Saito T
Department of Biological and Chemical Engineering, Faculty of Engineering, Gunma University, Kiryu, Japan.
Int J Biol Macromol. 1999 May;24(4):311-8. doi: 10.1016/s0141-8130(98)00064-6.
Copolyesters of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) were produced by Burkholderia cepacia D1 at 30 degrees C in nitrogen-free culture solutions containing n-butyric acid and/or n-valeric acid. When n-valeric acid was used as the sole carbon source, the 3HV fraction in copolyester increased from 36 to 90 mol% as the concentration of n-valeric acid in the culture solution increased from 1 to 20 g/l. The addition of n-butyric acid to the culture solution resulted in a decrease in the 3HV fraction in copolyester. The copolymers biosynthesized by this method were mixtures of random copolymers having a wide variety of composition of the 3HV component. The melting points of the fractionated copolymers show a concave curve with the minimum at the 3HV content of approximately 40 mol%. The alpha-parameter of lattice indices of the P(3HB) crystal for the fractionated copolymers largely increased as the 3HV composition increased. Biodegradability of the copolymer increased with the lower content of 3HV composition and/or the lower crystallinity.
洋葱伯克霍尔德菌D1在30℃下于含有正丁酸和/或正戊酸的无氮培养液中生产3-羟基丁酸（3HB）和3-羟基戊酸（3HV）的共聚酯。当使用正戊酸作为唯一碳源时，随着培养液中正戊酸浓度从1 g/L增加到20 g/L，共聚酯中3HV组分的比例从36 mol%增加到90 mol%。向培养液中添加正丁酸会导致共聚酯中3HV组分的比例降低。通过该方法生物合成的共聚物是具有多种3HV组分组成的无规共聚物的混合物。分级共聚物的熔点呈现出一条凹曲线，在3HV含量约为40 mol%时达到最低。随着3HV组成的增加，分级共聚物的P(3HB)晶体晶格指数的α参数大幅增加。共聚物的生物降解性随着3HV组成含量降低和/或结晶度降低而增加。
