Insomphun Chayatip, Kobayashi Shingo, Fujiki Tetsuya, Numata Keiji
Enzyme Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan.
Kaneka Corporation, 1-8 Miyamae-cho, Takasago-cho, Takasago, Hyogo, 676-8688, Japan.
AMB Express. 2016 Dec;6(1):29. doi: 10.1186/s13568-016-0200-5. Epub 2016 Apr 14.
Polyhydroxyalkanoates (PHAs) containing hydroxyl groups in a side chain were produced in recombinant Escherichia coli JM109 using glycolate as the sole carbon source. The propionate-CoA transferase (pct) gene from Megasphaera elsdenii and the β-ketothiolase (bktB) gene and phaCAB operon from Ralstonia eutropha H16 were introduced into E. coli JM109. A novel monomer containing a hydroxyl group, dihydroxybutyrate (DHBA), was the expected product of the condensation of glycolyl-CoA and acetyl-CoA by BktB. The recombinant strain produced a PHA containing 1 mol% DHBA. The incorporation of DHBA may have been restricted because the expression of phaAB1 competes for acetyl-CoA. The PHA containing DHBA units were evaluated regarding thermal properties, such as melting temperature, glass transition temperature and thermal degradation temperature. The current study demonstrates a potential use of PHA containing hydroxyl groups as renewable resources in biological materials.
以乙醇酸作为唯一碳源，在重组大肠杆菌JM109中合成了侧链含有羟基的聚羟基脂肪酸酯（PHA）。将来自埃氏巨球形菌的丙酸辅酶A转移酶（pct）基因、来自嗜麦芽窄食单胞菌H16的β-酮硫解酶（bktB）基因和phaCAB操纵子导入大肠杆菌JM109。一种含有羟基的新型单体二羟基丁酸（DHBA）是BktB催化乙醇酰辅酶A和乙酰辅酶A缩合反应的预期产物。该重组菌株产生了一种含有1摩尔% DHBA的PHA。DHBA的掺入可能受到限制，因为phaAB1的表达会竞争乙酰辅酶A。对含有DHBA单元的PHA的热性能进行了评估，如熔点、玻璃化转变温度和热降解温度。当前研究表明，含有羟基的PHA作为生物材料中的可再生资源具有潜在用途。
