Enhancing Production of Medium-Chain-Length Polyhydroxyalkanoates from Pseudomonas sp. SG4502 by tac Enhancer Insertion
| 第一作者： |
Song, Linxin |
| 英文第一作者： |
Song, Linxin |
| 联系作者： |
Han, Xuerong |
| 英文联系作者： |
Han, Xuerong |
| 发表年度： |
2023 |
| 卷： |
15 |
| 摘要： |
Pseudomonas sp. SG4502 screened from biodiesel fuel by-products can synthesize medium-chain-length polyhydroxyalkanoates (mcl-PHAs) using glycerol as a substrate. It contains a typical PHA class II synthase gene cluster. This study revealed two genetic engineering methods for improving the mcl-PHA accumulation capacity of Pseudomonas sp. SG4502. One way was to knock out the PHA-depolymerase phaZ gene, the other way was to insert a tac enhancer into the upstream of the phaC1/phaC2 genes. Yields of mcl-PHAs produced from 1% sodium octanoate by +(tac-phaC2) and ?phaZ strains were enhanced by 53.8% and 23.1%, respectively, compared with those produced by the wild-type strain. The increase in mcl-PHA yield from +(tac-phaC2) and ?phaZ was due to the transcriptional level of the phaC2 and phaZ genes, as determined by RT-qPCR (the carbon source was sodium octanoate). 1H-NMR results showed that the synthesized products contained 3-hydroxyoctanoic acid (3HO), 3-hydroxydecanoic acid (3HD) and 3-hydroxydodecanoic acid (3HDD) units, which is consistent with those synthesized by the wild-type strain. The size-exclusion chromatography by GPC of mcl-PHAs from the (?phaZ), +(tac-phaC1) and +(tac-phaC2) strains were 2.67, 2.52 and 2.60, respectively, all of which were lower than that of the wild-type strain (4.56). DSC analysis showed that the melting temperature of mcl-PHAs produced by recombinant strains ranged from 60 degrees C to 65 degrees C, which was lower than that of the wild-type strain. Finally, TG analysis showed that the decomposition temperature of mcl-PHAs synthesized by the (?phaZ), +(tac-phaC1) and +(tac-phaC2) strains was 8.4 degrees C, 14.7 degrees C and 10.1 degrees C higher than that of the wild-type strain, respectively. |
| 刊物名称： |
POLYMERS |
| 参与作者： |
Song, LX (Song, Linxin) [1] , [2] ; Wang, M (Wang, Ming) [3] ; Yu, DB (Yu, Dengbin) [1] , [2] ; Li, Y (Li, Yu) [1] , [4] ; Yu, HW (Yu, Hongwen) [5] ; Han, XR (Han, Xuerong) [1] , [3] |
吉公网安备22017302000214号
