Isemori Yuichi, Tajima Koichiro, Tanaka Syogo, Yu Fang, Ishida Kazuki, Inoue Yoshio
Department of Biomolecular Engineering, Tokyo Institute of Technology, Nagatsuta 4259-B-55, Yokohama 226-8501, Japan.
Macromol Biosci. 2006 Oct 20;6(10):818-26. doi: 10.1002/mabi.200600133.
A series of P(3HB-co-3MP)s with different 3MP unit content was biosynthesized by the fermentation of W. eutropha in a medium containing sodium gluconate and DTDP as carbon sources at different pH conditions ranging from pH 6.0 to 8.0. The P(3HB-co-3MP) samples were fractioned using the solvent/nonsolvent mixed solvent chloroform/heptane and the comonomer unit composition was investigated. It was found that W. eutropha produces P(3HB-co-3MP)s with extremely different 3MP unit content ranging from 3.6 to 70.0 mol-%, depending on the pH value of the fermentation medium. The copolyester samples produced in mild basic medium have a considerably narrower compositional distribution than the samples from acidic medium. The highest polymer yield was obtained at pH 8.0.DSC diagram for P(3HB-co-3MP)s biosynthesized in different pH medium. [graph: see text] DSC diagram for P(3HB-co-3MP)s biosynthesized in different pH medium.
在含有葡萄糖酸钠和DTDP作为碳源的培养基中，于pH值范围为6.0至8.0的不同条件下，通过真养产碱杆菌的发酵生物合成了一系列具有不同3-甲基戊酸（3MP）单元含量的聚（3-羟基丁酸酯-co-3-甲基戊酸酯）[P(3HB-co-3MP)]。使用溶剂/非溶剂混合溶剂氯仿/庚烷对P(3HB-co-3MP)样品进行分级，并研究其共聚单体单元组成。结果发现，根据发酵培养基的pH值，真养产碱杆菌产生的P(3HB-co-3MP)中3MP单元含量差异极大，范围为3.6至70.0摩尔％。在弱碱性培养基中产生的共聚酯样品的组成分布比酸性培养基中的样品窄得多。在pH 8.0时获得了最高的聚合物产率。在不同pH培养基中生物合成的P(3HB-co-3MP)的DSC图。[图：见正文]在不同pH培养基中生物合成的P(3HB-co-3MP)的DSC图。
