JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Yao Lu,Di Liu,Long Wang,Yongai Ma,Tai-Ping Fan,Huaxiang Deng,Yujie Cai
(−)-α-Bisabolol exhibits analgesic, anti-inflammatory, and skin-soothing properties and is widely applied in the cosmetic and pharmaceutical industries. The use of plant essential oil distillation or chemical synthesis to produce (−)-α-bisabolol is both inefficient and unsustainable. Currently, the microbial production of (−)-α-bisabolol mainly relies on Escherichia coli and Saccharomyces cerevisiae as chassis strains; however, high concentrations of (−)-α-bisabolol have certain toxicity to the strain. This study uses synthetic biology and metabolic engineering strategies to redesign a solvent-tolerant Serratia marcescens for the efficient production of (−)-α-bisabolol. By introducing the Haloarchaea-type mevalonate (MVA) pathway and the (−)-α-bisabolol biosynthesis pathway, we successfully constructed a strain capable of producing (−)-α-bisabolol. The coexpression of the chaperone protein DnaK/J significantly enhanced the soluble expression of the (−)-α-bisabolol synthase, resulting in a 10% increase in (−)-α-bisabolol titer. Furthermore, knockout of the PhoA gene, which reduced the formation of the byproduct farnesol (FOH), further increased the (−)-α-bisabolol titer to 3.21 g/L. In a 5 L bioreactor, S. marcescens achieved a final (−)-α-bisabolol titer of 30.2 g/L, representing the highest titer reported to date. This research provides guidance for the production of (−)-α-bisabolol in nonmodel microorganisms without the requirement for induction.
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Synthetic and Systems Biotechnology
·
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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JOURNAL OF HAZARDOUS MATERIALS
·
2025
·
IF 11.3
Siyu Wang,Jie Han,Ziyi Ge,Xu Su,Yongjia Shi,Fan Xia,Yuwei Huang,Jun Meng
Undissolved biochar (UBC) plays a key role in persistently affecting bacterial characteristics after loss of dissolved biochar. However, its potential role as electron shuttle mediating tetracycline (TC) removal by bacteria is less understood. Result demonstrated UBC (700°C) coupled strain MSM2304 resulted in 72.19 % of TC biodegradation (37.76 % in free cells). UBC improved nutrients usage of TOC and TN to enhance cells proliferation, and facilitated biofilms formation and secretion of redox-active-related extracellular polymeric substances (EPS) including protein (40 % higher) and humus (30 % higher). Moreover, UBC optimized cells oxidative stress indicators including reactive oxygen species (40 % lower), total antioxidant capacity (30 % higher), superoxide dismutase (35 % higher), and catalase (30 % higher) during TC exposure. Importantly, UBC not only accelerated electron transfer from intracellular into extracellular by stimulating cytochrome C reductase activity and cytochrome C development, also decreased extracellular electron transfer resistance between MSM2304 and TC from 231.7 to 109.5 Ω, proved by cyclic voltammetry and electrochemical impedance spectra of EPS, and helped quinone moieties formation on UBC through C O and C C or C O production determined by FTIR and XPS. These findings indicate UBC could be as electron shuttle and contribute to provide a better understanding of interactions between biochar and microorganism.
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Foods
·
2024
·Vol. 13
·期 4
·527
·
IF 4.7
Xu Geng,Yi Li,Ruizhe Wang,Song Jiang,Yingchao Liang,Tao Li,Chen Li,Jin Tao,Zhengqiang Li
The escalating demand for processed foods has led to the widespread industrial use of glucose isomerase (GI) for high-fructose corn syrup (HFCS) production. This reliance on GIs necessitates continual Co2+supplementation to sustain high catalytic activity across multiple reaction cycles. In this study,Serratia marcescensGI (SmGI) was immobilized onto surfaces of the metal-organic framework (MOF) material MOF (Co)-525 to generate MOF (Co)-525-GI for use in catalyzing glucose isomerization to generate fructose. Examination of MOF (Co)-525-GI structural features using scanning electron microscopy-energy dispersive spectroscopy, Fourier-transform infrared spectroscopy, and ultraviolet spectroscopy revealed no structural changes afterSmGI immobilization and the addition of Co2+. Notably, MOF (Co)-525-GI exhibited optimal catalytic activity at pH 7.5 and 70 °C, with a maximum reaction rate (Vmax) of 37.24 ± 1.91 μM/min and Km value of 46.25 ± 3.03 mM observed. Remarkably, immobilizedSmGI exhibited sustained high catalytic activity over multiple cycles without continuous Co2+infusion, retaining its molecular structure and 96.38% of its initial activity after six reaction cycles. These results underscore the potential of MOF (Co)-525-GI to serve as a safer and more efficient immobilized enzyme technology compared to traditional GI-based food-processing technologies.
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