Metabolic engineering of Pseudomonas mendocina NK-01 for enhanced production of medium-chain-length polyhydroxyalkanoates with enriched content of the dominant monomer
Metabolic engineering of Pseudomonas mendocina NK-01 for enhanced production of medium-chain-length polyhydroxyalkanoates with enriched content of the dominant monomer
复制标题
门多萨假单胞菌 NK-01 的代谢工程可增强主要单体含量丰富的中链长度聚羟基脂肪酸酯的生产
DOI：
10.1016/j.ijbiomac.2019.11.044
复制
发表时间：
--
期刊：
影响因子：
--
通讯作者：
Ruihua Liu
中科院分区：
文献类型：
--
作者：
Fengjie Zhao;Fanyang He;Xiangsheng Liu;Jie Shi;Jingnan Liang;Shufang Wang;Chao Yang;Ruihua Liu
本研究中，6个基因参与了P.缺失mendocinaNK-01构建突变株NKU-β 1和NKU-β5。与野生株NKU相比，用辛酸钠和癸酸钠培养，NKU-β 5的mcl-PHA效价分别提高了5.58倍和4.85倍。十二烷酸可使NKU-β 1的mcl-PHA效价提高10.02倍。NKU-β 5合成的mcl-PHA中，主要单体3-羟基癸酸酯（3 HD）和3-羟基十二酸酯（3 HDD）的含量明显提高，分别为90.01mol%和58.60mol%。进一步删除基因phaGandphaZ，3 HD和3 HDD含量进一步提高，分别为94.71和68.67mol%。本研究中获得的mcl-PHA的最高分子量为80.79 × 104 Da，高于以前报道的mcl-PHA。随着主单体含量的增加，合成的mcl-PHA具有较好的热性能、力学性能和结晶性能。有趣的是，NKU-β 5的细胞尺寸比NKU大，这是由于积累了更多的PHA颗粒。本研究表明，一个系统的代谢工程方法，P。mendocinaNK-01能显著提高mcl-PHA的效价、优势单体含量和物理性质。
In this study, six genes involved inβ-oxidation pathway ofP. mendocinaNK-01 were deleted to construct mutant strains NKU-∆β1and NKU-∆β5. Compared with the wild strain NKU, the mcl-PHA titers of NKU-∆β5were respectively increased by 5.58- and 4.85-fold for culturing with sodium octanoate and sodium decanoate. And the mcl-PHA titers of NKU-∆β1was increased by 10.02-fold for culturing with dodecanoic acid. The contents of dominant monomers 3-hydroxydecanoate (3HD) and 3-hydroxydodecanoate (3HDD) of the mcl-PHA synthesized by NKU-∆β5were obviously increased to 90.01 and 58.60 mol%, respectively. Further deletion of genesphaGandphaZ, the 3HD and 3HDD contents were further improved to 94.71 and 68.67 mol%, respectively. The highest molecular weight of mcl-PHA obtained in this study was 80.79 × 104Da, which was higher than the previously reported mcl-PHA. With the increase of dominant monomer contents, the synthesized mcl-PHA showed better thermal properties, mechanical properties and crystallization properties. Interestingly, the cell size of NKU-∆β5was larger than that of NKU due to the accumulation of more PHA granules. This study indicated that a systematically metabolic engineering approach forP. mendocinaNK-01 could significantly improve the mcl-PHA titer, dominant monomer contents and physical properties of mcl-PHA.