【摘要】：研究采用重疊延伸PCR合成技術(shù)將乳酸乳球菌(Lactococcus lactis)分泌蛋白基因序列usp45(81bp)和瑞氏木霉(Trichoderma reesei)β-1,4-葡聚糖內(nèi)切酶成熟蛋白序列egl3(657bp)連接成融合基因usp45-egl3,構(gòu)建了分泌型重組質(zhì)粒pMG36eusp45-egl3及重組乳酸乳球菌L.lactis subsp.lactis MG1363/pMG36e-usp45-egl3,分析了重組乳酸乳球菌表達β-1,4-葡聚糖內(nèi)切酶的效果及其降解濾紙和小麥秸稈的能力。結(jié)果表明,重組乳酸乳球菌L.lactis subsp.lactis MG1363/pMG36e-usp45-egl3經(jīng)28h培養(yǎng)能胞外分泌酶活為1 016U/L的β-1,4-葡聚糖內(nèi)切酶,有效地降解了羧甲基纖維素鈉。在30℃恒溫培養(yǎng)10d時,重組乳酸乳球菌L.lactis subsp.lactis MG1363/pMG36e-usp45-egl3降解濾紙和小麥秸稈為其提供發(fā)酵底物,分別產(chǎn)生乳酸2.55g/L和6.95g/L,pH分別降至5.10和4.84,干物質(zhì)降解率分別為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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