β-1,4-葡聚糖内切酶egl3基因在乳酸乳球菌中分泌表达的研究

发布时间：2019-03-29 09:07

【摘要】：研究采用重叠延伸PCR合成技术将乳酸乳球菌(Lactococcus lactis)分泌蛋白基因序列usp45(81bp)和瑞氏木霉(Trichoderma reesei)β-1,4-葡聚糖内切酶成熟蛋白序列egl3(657bp)连接成融合基因usp45-egl3,构建了分泌型重组质粒pMG36eusp45-egl3及重组乳酸乳球菌L.lactis subsp.lactis MG1363/pMG36e-usp45-egl3,分析了重组乳酸乳球菌表达β-1,4-葡聚糖内切酶的效果及其降解滤纸和小麦秸秆的能力。结果表明,重组乳酸乳球菌L.lactis subsp.lactis MG1363/pMG36e-usp45-egl3经28h培养能胞外分泌酶活为1 016U/L的β-1,4-葡聚糖内切酶,有效地降解了羧甲基纤维素钠。在30℃恒温培养10d时,重组乳酸乳球菌L.lactis subsp.lactis MG1363/pMG36e-usp45-egl3降解滤纸和小麦秸秆为其提供发酵底物,分别产生乳酸2.55g/L和6.95g/L,pH分别降至5.10和4.84,干物质降解率分别为4.22%和29.36%。
[Abstract]:The fusion gene usp45 (81bp) of Lactococcus lactis (Lactococcus lactis) secretory protein gene sequence usp45 (81bp) and (Trichoderma reesei) 尾-1, 4-glucan endonuclease mature protein sequence egl3 (657bp) of Trichoderma reesei were ligated to form fusion gene usp45-egl3, by overlap extension PCR synthesis technique. The secretory recombinant plasmid pMG36eusp45-egl3 and recombinant Lactococcus lactis L.lactis subsp.lactis MG1363/pMG36e-usp45-egl3, were constructed to analyze the effect of 尾-1, 4-glucan endonuclease expression and the ability of degrading filter paper and wheat straw by recombinant Lactococcus lactis. The results showed that the recombinant Lactococcus lactis L.lactis subsp.lactis MG1363/pMG36e-usp45-egl3 could efficiently degrade sodium carboxymethyl cellulose (CMC) by 尾-1,4-glucan endonuclease with extracellular activity of 1 016U/L after 28 h culture. When cultured at 30 鈩，

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