APPLIED MICROBIOLOGY AND BIOTECHNOLOGY
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2020
·Vol. 104
·期 6
·2481-2488
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IF 3.53
Xu Da,Fang Mengjun,Wang Haijiao,Huang Lei,Xu Qinyang,Xu Zhinan
5-Hydroxytryptophan (5-HTP) is the precursor of the neurotransmitter serotonin and has been used for the treatment of various diseases such as depression, insomnia, chronic headaches, and binge eating associated obesity. The production of 5-HTP had been achieved in our previous report, by the development of a recombinant strain containing two plasmids for biosynthesis of L-tryptophan (L-trp) and subsequent hydroxylation. In this study, the L-trp biosynthetic pathway was further integrated into the E. coli genome, and the promoter strength of 3-deoxy-7-phosphoheptulonate synthase, which catalyzes the first step of L-trp biosynthesis, was engineered to increase the production of L-trp. Hence, the 5-HTP production could be manipulated by the regulation of copy number of L-trp hydroxylation plasmid. Finally, the 5-HTP production was increased to 1.61 g/L in the shaking flasks, which was 24% improvement comparing to the original producing strain, while the content of residual L-trp was successfully reduced from 1.66 to 0.2 g/L, which is beneficial for the downstream separation and purification. Our work shall promote feasible progresses for the industrial production of 5-HTP.
研究领域:
生物工程
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微生物学
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分子生物学
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Synthetic and Systems Biotechnology
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2025
·
IF 4.4
Wei Li,Di Liu,Linbo Gou,Shengfang Wu,Xiuwen Zhou,Tai-Ping Fan,Long Wang,Yujie Cai
(-)-α-Bisabolol, a valuable monocyclic sesquiterpene alcohol, has garnered significant attention in the pharmaceutical and cosmetic industries due to its remarkable anti-inflammatory, antibacterial, and skin-care properties. In this study, Serratia marcescens HBQA7 ( S. marcescens HBQA7), a non-model strain resistant to terpenoid toxicity, was used as the production host, and the expression intensities of different integration sites were screened. The complete (-)-α-bisabolol synthesis pathway was integrated into these sites, achieving a production titer of 3.5 g L −1 . On this basis, by knocking out competitive pathway genes (such as slaB and adhE ) and global regulatory factors ( arcA and iclR ), and introducing efficient glucose transport and activation ( glf and glk ), the shake flask fermentation titer was increased to 7.21 g L −1 . Through optimization of fermentation culture by orthogonal experiments and others, the titer was further increased to 9.90 g L −1 . Finally, through the fed-batch fermentation process conducted in a 50 L bioreactor, a titer of 102.3 g L −1 was achieved after 110 h of cultivation. The productivity reached 0.93 g L −1 h −1 . This study not only establishes the most efficient microbial production system for (-)-α-bisabolol reported to date, but also demonstrates the outstanding potential of S. marcescens as a chassis for terpenoid biosynthesis. It provides a novel strategy for the industrial production of high-value terpenoids.
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ACS Applied Nano Materials
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2022
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IF 6.14
Jiaying Li,Shuojun Li,Moqing Du,Zhiyong Song,Heyou Han
Delivery and expression of exogenous plasmid DNA (pDNA) into mature plants for plant genetic engineering mainly rely on Agrobacterium-mediated transformation and biolistic bombardment. Meanwhile, the process of pDNA entering the nucleus via traditional methods is random and there is no nuclear targeting effect. Here, we reported a dual-peptide-based gene delivery system to achieve nuclear delivery of exogenous pDNA in mature plants. This system is a combination of engineered peptides composed of nuclear location signal (NLS) fusion with the DNA binding domain (KH)9 and cell-penetrating peptides (CPPs), which could bind pDNA to form a sphere-like CPP-NLS(KH)-pDNA nanocomplex. We found that this system could overcome barriers of the nuclear pore complexes (NPCs) and deliver exogenous pDNA entering the nucleus efficiently. Besides, we demonstrated that the CPP-NLS(KH)-pDNA nanocomplex could efficiently cross the rigid plant cell wall into the nucleus at 24 h after treatment and bring about a transient expression in plant suspension cells and living plants 3 days after treatment. This strategy has obvious advantages of good biocompatibility, nongenomic integration, and nonspecies limitation and shows the potential of NLS peptides as gene carriers, which would provide a delivery tool to complement preset methods serving plant genetic engineering.
研究领域:
植物科学
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遗传工程
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分子生物学
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Nature Communications
·
2024
·Vol. 15
·期 1
·1-17
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IF 14.7
Zhao Yiquan,Xue Le,Huang Zhiyi,Lei Zixian,Xie Shiyu,Cai Zhenzhen,Rao Xinran,Zheng Ze,Xiao Ning,Zhang Xiaoyu,Ma Fuying,Yu Hongbo,Xie Shangxian
Exploring microorganisms with downstream synthetic advantages in lignin valorization is an effective strategy to increase target product diversity and yield. This study ingeniously engineers the non-lignin-degrading bacterium Ralstonia eutropha H16 (also known as Cupriavidus necator H16) to convert lignin, a typically underutilized by-product of biorefinery, into valuable bioplastic polyhydroxybutyrate (PHB). The aromatic metabolism capacities of R. eutropha H16 for different lignin-derived aromatics (LDAs) are systematically characterized and complemented by integrating robust functional modules including O- demethylation, aromatic aldehyde metabolism and the mitigation of by-product inhibition. A pivotal discovery is the regulatory element PcaQ, which is highly responsive to the aromatic hub metabolite protocatechuic acid during lignin degradation. Based on the computer-aided design of PcaQ, we develop a hub metabolite-based autoregulation (HMA) system. This system can control the functional genes expression in response to heterologous LDAs and enhance metabolism efficiency. Multi-module genome integration and directed evolution further fortify the strain’s stability and lignin conversion capacities, leading to PHB production titer of 2.38 g/L using heterologous LDAs as sole carbon source. This work not only marks a leap in bioplastic production from lignin components but also provides a strategy to redesign the non-LDAs-degrading microbes for efficient lignin valorization.
研究领域:
生物技术
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代谢工程
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生物聚合物
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微生物生物技术
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高影响因子
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