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木质素降解菌枯草芽孢杆菌YY-10的特性表征及工程菌构建

Characterization of lignin-degrading Bacillus subtilis YY-10 and construction of genetically engineered strains

  • 摘要: 为有效利用烟草废弃物生产烟用酶制剂, 以烟草源耐烟碱木质素降解菌枯草芽孢杆菌(Bacillus subtilis)YY-10为研究对象, 通过遗传和分泌蛋白组成分析、基因编辑, 研究其作为产酶宿主菌的可行性。结果表明: ①枯草芽孢杆菌YY-10基因组含有1个环形染色体, 编码4 252个基因, 含多种碳水化合物活性酶, 分泌蛋白中富含果胶裂解酶和淀粉酶等降解酶。②以YY-10为宿主菌构建的产果胶酶基因工程菌(YY-10-pelA)可实现目标酶蛋白的表达与分泌, 酶活性较野生菌提高约3倍, 且具有在营养胁迫条件下利用碱性木素生长的能力。③对YY-10菌株与传统枯草芽孢杆菌宿主菌产酶能力及酶制剂的应用效果的分析发现, YY-10菌株作为烟用酶制剂产酶宿主菌在提高烟草废弃物利用率和烟草的感官舒适性方面具有明显优势。

     

    Abstract: In order to promote effective utilization of tobacco waste and sustainable production of tobacco enzyme additives, Bacillus subtilis YY-10, a nicotine-resistant lignin-degrading bacterium derived from tobacco, was investigated by genome sequencing, exoprotein composition analysis and gene editing techniques to evaluate its feasibility as an enzyme-producing host. The results showed that: 1) The YY-10 genome had a circular chromosome encoding 4 252 genes, which contained various active carbohydrate enzymes. The exoproteins of YY-10 were rich in pectate lyase and amylase. 2) A pectate lyase expression system was developed and introduced into the YY-10 host, resulting in a genetically engineered strain, YY-10-pelA. The strain achieved expression and secretion of the target enzyme, and exhibited enzyme activity about three times higher than the wild type, and demonstrated the ability to utilize alkaline lignin for growth under nutrient stress. 3) Compared with well-established B. subtilis hosts, YY-10 as an enzyme-producing host using tobacco waste for enzyme preparation showed considerable enzyme expression capacity and outstanding advantages in improving the sensory quality of tobacco.

     

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