Morphology engineering for enhanced production of medium-chain-length polyhydroxyalkanoates in Pseudomonas mendocina NK-01.
Morphology engineering for enhanced production of medium-chain-length polyhydroxyalkanoates in Pseudomonas mendocina NK-01.
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用于增强门多萨假单胞菌 NK-01 中链长聚羟基脂肪酸酯产量的形态学工程。
DOI：
10.1007/s00253-018-9546-8
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通讯作者：
Yang Chao
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作者：
Zhao Fengjie;Yang Chao
聚羟基脂肪酸酯（PHA）可以由微生物从可再生资源中生产，被认为是替代石油基塑料的有前途的生物塑料。本实验室前期分离得到一株中链PHAs（mcl-PHA）生产菌株Pseudomonas mendocinaNK-01，目前已获得其全基因组序列。操纵细胞形态相关基因的形态学工程已应用于增强细胞内生物聚合物短链 PHA (scl-PHA) 的积累。但目前尚未见通过形态工程提高mcl-PHA产率的报道。在这项工作中，通过在P.mendocinaNKU中基因敲除和过表达，深入研究了几个已充分表征的细胞形态相关基因，包括细胞裂变环（Z环）定位基因minCD、肽聚糖降解基因genenlpD、肌动蛋白样细胞骨架蛋白genemreB、Z环形成geneftsZ和FtsZ抑制剂基因ulA，以了解它们对细胞形态和mcl-PHA积累的影响。 P.mendocinaNK-01 的 auppknockout 突变体。对于aminCD敲除突变体P.mendocinaNKU-ΔminCD，平均细胞长度明显增加，mcl-PHA产量提高。然而，与P.mendocinaNKU相比，thenlpD敲除突变体具有更短的细胞长度和更低的mcl-PHA产量。 mreBinP.mendocinaNKU 的过度表达产生球形细胞。当ftsZ在P.mendocinaNKU中过表达时，细胞分裂加速，mcl-PHA滴度提高。此外，mreB、ftsZ、orsulA 在 P.mendocinaNKU-ΔminCD 中过表达。因此，与携带空载体的P.mendocinaNKU-ΔminCD相比，mcl-PHA滴度均有所增加。最终在ftsZ-过表达NKU-ΔminCD中实现了多重裂变模式。在这项工作中，改进了 mcl-PHA inP 的生产。 mendocinaNK-01是通过形态工程实现的。这项工作提供了一种增强 mcl-PHA 生产菌株中 mcl-PHA 积累的替代策略。
Polyhydroxyalkanoates (PHAs) can be produced by microorganisms from renewable resources and are regarded as promising bioplastics to replace petroleum-based plastics. A medium-chain-length PHAs (mcl-PHA)-producing strainPseudomonas mendocinaNK-01 was isolated previously by our lab and its whole-genome sequence is currently available. Morphology engineering of manipulating cell morphology–related genes has been applied for enhanced accumulation of the intracellular biopolymer short-chain-length PHAs (scl-PHA). However, it has not yet been reported to improve the yield of mcl-PHA by morphology engineering so far. In this work, several well-characterized cell morphology–related genes, including the cell fission ring (Z-ring) location genesminCD, peptidoglycan degradation genenlpD, actin-like cytoskeleton protein genemreB, Z-ring formation geneftsZ, and FtsZ inhibitor genesulA, were intensively investigated for their impacts on the cell morphology and mcl-PHA accumulation by gene knockout and overexpression inP.mendocinaNKU, auppknockout mutant ofP.mendocinaNK-01. For aminCDknockout mutantP.mendocinaNKU-∆minCD, the average cell length was obviously increased and the mcl-PHA production was improved. However, thenlpDknockout mutant had a shorter cell length and lower mcl-PHA yield compared withP.mendocinaNKU. Overexpression ofmreBinP.mendocinaNKU resulted in spherical cells. WhenftsZwas overexpressed inP.mendocinaNKU, the cell division was accelerated and the mcl-PHA titer was improved. Furthermore,mreB,ftsZ, orsulAwas overexpressed inP.mendocinaNKU-∆minCD. Consequently, the mcl-PHA titers were all increased compared withP.mendocinaNKU-∆minCDcarrying the empty vector. The multiple fission pattern was finally achieved inftsZ-overexpressing NKU-∆minCD. In this work, improved production of mcl-PHA inP. mendocinaNK-01 has been achieved by morphology engineering. This work provides an alternative strategy to enhance mcl-PHA accumulation in mcl-PHA-producing strains.