枯草芽孢杆菌基因修饰生产核黄素

发布时间：2018-09-08 18:18

【摘要】：【目的】研究枯草芽孢杆菌核黄素合成途径、木糖代谢相关基因修饰对核黄素合成的影响。【方法】单独过表达或共同过表达核黄素操纵子中的基因、过表达木糖代谢相关基因构建相应的重组菌株。通过测定和比较重组菌株摇瓶发酵的核黄素产量和生物量,表征各个基因修饰的效应。采用摇瓶和5 L罐发酵,考察木糖作为主要碳源以及木糖与蔗糖共代谢对核黄素发酵的影响。【结果】ribA基因单独过表达,使核黄素产量提高99%,但生物量降低30%,出现细胞自溶现象。ribA-ribH基因共表达,使核黄素产量提高280%,并且无细胞自溶和生物量下降现象。1.5%蔗糖与6.5%木糖作为碳源,5 L发酵罐发酵70 h,核黄素产量达到3.6 g/L,与8%蔗糖为碳源的发酵相比,核黄素产量提高80%。木糖代谢相关基因过表达,均明显降低核黄素产量。【结论】与ribA基因单独过表达相比,ribA-ribH基因共表达可有效避免细胞自溶现象,并能进一步提高核黄素产量。蔗糖与木糖共代谢,能够改善前体物供给,有利于提高核黄素产量。
[Abstract]:[objective] to study the riboflavin synthesis pathway of Bacillus subtilis and the effect of xylose metabolism related gene modification on riboflavin synthesis. Overexpression of xylose metabolism related genes to construct the corresponding recombinant strain. The yield and biomass of riboflavin in shaking flask fermentation of recombinant strain were determined and compared to characterize the effect of each gene modification. The effects of xylose as the main carbon source and the co-metabolism of xylose and sucrose on riboflavin fermentation were investigated by using shaking flask and 5 L fermenter. [results] ribA gene was overexpressed alone. The yield of riboflavin was increased by 99%, but the biomass decreased by 30%, which resulted in the co-expression of the. RibA-ribH gene. The riboflavin yield was increased by 280g / L, and the riboflavin production reached 3.6 g / L after 70 h fermentation in a fermentor containing 1.5% sucrose and 6.5% xylose as carbon source. Compared with the fermentation with 8% sucrose as carbon source, the riboflavin yield increased by 80%. Overexpression of xylose metabolism-related genes significantly reduced riboflavin production. [conclusion] compared with ribA gene overexpression alone, coexpression of ribA-ribH gene can effectively avoid the phenomenon of cell autolysis and further increase riboflavin production. Sucrose and xylose metabolism can improve the supply of precursors and increase the yield of riboflavin.
【作者单位】：天津大学化工学院系统生物工程教育部重点实验室;天津医学高等专科学校;
【基金】：国家高技术研究发展计划(863计划)(No.2012AA02A701)~~
【分类号】：TQ924;Q78

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