Li Mengyi, Ma Yueyuan, Zhang Xu, Zhang Lizhan, Chen Xinyu, Ye Jian-Wen, Chen Guo-Qiang
School of Life Sciences, Tsinghua University, Beijing, 100084, China.
Tsinghua-Peking Center of Life Sciences, Tsinghua University, Beijing, 100084, China.
Adv Mater. 2021 Oct;33(41):e2102766. doi: 10.1002/adma.202102766. Epub 2021 Jul 28.
Microbial polyhydroxyalkanoates (PHA) containing short- and medium/long-chain-length monomers, abbreviated as SCL-co-MCL/LCL PHAs, generate suitable thermal and mechanical properties. However, SCL-co-MCL/LCL PHAs with carbon chain longer than nine are difficult to synthesize due to the low specificity of PHA synthase PhaC and the lack of either SCL- or MCL/LCL monomer precursor fluxes. This study succeeds in reprogramming a β-oxidation weakened Pseudomonas entomophila containing synthesis pathways of SCL 3-hydroxybutyryl-CoA (3HB) from glucose and MCL/LCL 3-hydroxyalkanoyl-CoA from fatty acids with carbon chain lengths from 9 to 18, respectively, that are polymerized under a low specificity PhaC to form P(3HB-co-MCL/LCL 3HA) copolymers. Through rational flux-tuning approaches, the optimized recombinant P. entomophila accumulates 55 wt% poly-3-hydroxybutyrate in 8.4 g L cell dry weight. Combined with weakened β-oxidation, a series of novel P(3HB-co-MCL/LCL 3HA) copolymers with over 60 wt% PHA in 9 g L cell dry weight have been synthesized for the first time. P. entomophila has become a high-performing platform to generate tailor-made new SCL-co-MCL/LCL PHAs.
含有短链和中/长链长度单体的微生物聚羟基脂肪酸酯（PHA），简称为SCL-co-MCL/LCL PHA，具有合适的热性能和机械性能。然而，由于PHA合酶PhaC的低特异性以及缺乏SCL或MCL/LCL单体前体通量，碳链长度超过9的SCL-co-MCL/LCL PHA难以合成。本研究成功地对一种β-氧化减弱的嗜虫假单胞菌进行了重编程，该菌分别含有从葡萄糖合成SCL 3-羟基丁酰辅酶A（3HB）和从碳链长度为9至18的脂肪酸合成MCL/LCL 3-羟基烷酰辅酶A的合成途径，这些物质在低特异性的PhaC作用下聚合形成P（3HB-co-MCL/LCL 3HA）共聚物。通过合理的通量调节方法，优化后的重组嗜虫假单胞菌在8.4 g/L细胞干重中积累了55 wt%的聚3-羟基丁酸酯。结合减弱的β-氧化，首次合成了一系列新型的P（3HB-co-MCL/LCL 3HA）共聚物，其在9 g/L细胞干重中的PHA含量超过60 wt%。嗜虫假单胞菌已成为生产定制新型SCL-co-MCL/LCL PHA的高性能平台。
