Efficient secretory expression of phospholipase D for the high-yield production of phosphatidylserine and phospholipid derivates from soybean lecithin

Phospholipase D(PLD)is an essential biocatalyst for the biological production of phosphatidylserine and phospholipid modification.However,the efficient heterologous expression of PLD is limited by its cell toxicity.In this study,a PLD was secretory expressed efficiently in Bacillus subtilis with an activity around 100 U/mL.A secretory expression system containing the signal peptide SPEstA and the dual-promoter PHpaII-SrfA was estab-lished,and the extracellular PLD activity further reached 119.22 U/mL through scale-up fermentation,191.30-fold higher than that of the control.Under optimum reaction conditions,a 61.61%conversion ratio and 21.07 g/L of phosphatidylserine production were achieved.Finally,the synthesis system of PL derivates was established,which could efficiently synthesis novel PL derivates.The results highlight that the secretory expression system constructed in this study provides a promising PLD producing strain in industrial application,and laid the foundation for the biosynthesis of phosphatidylserine and other PL derivates.As far as we know,this work re-ports the highest level of extracellular PLD expression to date and the enzymatic production of several PL der-ivates for the first time.

Recent progress of W_(18)O_(49)nanowires for energy conversion and storage

W_(18)O_(49)nanowires(W_(18)O_(49)NWs)with unique one-dimension structures and excellent electron/ions transport properties have attracted increasing attention in academia and industry because of their potential applications in many energy-related devices.In the past decades,many research articles related to W_(18)O_(49)have been published,but there are insufficient review articles focusing on W_(18)O_(49)NWs.In this review,we present the crystal structure of W_(18)O_(49)and briefly introduce the synthesis methods and growth mechanism of W_(18)O_(49)NWs.Moreover,their applications in energy conversion and storage devices are summarized.Finally,the current challenges and opportunities for applying W_(18)O_(49)NWs are provided.We hope this review can promote the development of W_(18)O_(49)NWs in energy conversion,storage,and other promising applications.

解聚型魔芋葡甘露聚糖的制备以及生理活性研究的进展（英文）

魔芋葡甘露聚糖是从魔芋块茎中提取的一种高分子水溶性多糖。近些年研究表明,其解聚产物,除了具有高溶解性和低粘度等良好的理化性质外,还具有调节微生物菌群结构、抗氧化、免疫调节等多种生理活性。本文重点综述了解聚型葡甘露聚糖的制备方法以及菌群调节功能。除此之外,对其抗氧化、免疫调节功能以及安全性评价也进行了全面的总结,为解聚型葡甘露聚糖的研究与应用提供一定的依据与思路。

Characterization,heterologous expression and engineering of trehalase for biotechnological applications

Trehalose is a non-reducing disaccharide connected byα-1,1-glycosidic bonds;it is widely distributed in bacteria,fungi,yeast,insects,and plant tissues and plays various roles.It can be hydrolyzed by trehalase into two glucose molecules.Trehalases from different sources have been expressed in Escherichia coli,Pichia pastoris,Saccharomyces cerevisiae,baculovirus-silkworm,and other expression systems;however,it is most common in E.coli.The structural characteristics of different glycoside hydrolase(GH)family trehalases and the sources of trehalase have been analyzed.The catalytic mechanism of GH37 trehalase has also been elucidated in detail.Moreover,the molecular modification of trehalase has mainly focused on directed evolution for improving enzyme activity.We comprehensively reviewed the current application status and adaptable transformations was comprehensively overviewed in the context of industrial performance.We suggest that the level of recombinant production is far from meeting industrial requirements,and the catalytic performance of trehalase needs to be improved urgently.Finally,we discuss developmental prospects and future trends.