Food-Grade Expression of d-Psicose 3-Epimerase with Tandem Repeat Genes in Bacillus subtilis

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• 作者：Weiwei He ; Wanmeng Mu ; Bo Jiang ; Xin Yan ; Tao Zhang
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2016
• 出版时间：July 20, 2016
• 年：2016
• 卷：64
• 期：28
• 页码：5701-5707
• 全文大小：406K
• 年卷期：0
• ISSN：1520-5118

文摘

An integrative food-grade expression system with tandem repeat target genes was constructed for the expression of d-psicose 3-epimerase (DPEase; EC 5.1.3.30). The DPEase gene fused with the P43 promoter constituted an independent monomeric expression cassette. Multimers of the expression cassette were constructed in vitro using the isocaudamer strategy. The recombinant integration plasmids pDG-nDPE (n = 1, 2, 3), which contained one, two, or three consecutive P43-DPEase tandem repeats, were integrated into the genome of B. subtilis. Then, the antibiotic resistance gene was deleted by the Cre/lox system, and the food-grade recombinant B. subtilis 1A751-nDPE (n = 1, 2, 3) with integrated tandem repeats of the P43-DPEase expression cassette were generated. The specific activity of the B. subtilis 1A751-3DPE was the highest among the recombinant strains and was ∼2.2-fold that of the 1A751-1DPE strain. Under the optimal conditions, 8 g/L of freeze-dried enzyme powder could convert 20% d-fructose (300 g/L) into d-allulose after 1 h.