一株降解纤维素放线菌的产纤维素酶基因克隆与表达

Cloning and expression of cellulase gene from a strain of cellulose degrading actinomycete

摘要:

【背景】纤维素在自然界中储量丰富，但天然纤维素的难降解性成为广泛应用纤维素资源的壁垒，近年来利用微生物来降解纤维素成为热点研究。【目的】筛选分离得到一株具有降解纤维素功能的放线菌菌株Lb1，通过全基因组测序确定其产纤维素酶关键基因5676，对基因5676进行克隆转化，使其在大肠杆菌中进行表达。【方法】通过基因工程技术将产纤维素基因连接到表达质粒上并导入表达菌株，对其降解纤维素生成葡萄糖的能力进行探究。【结果】将Lb1菌株的16S rRNA基因进行比对，确定菌株Lb1属于链霉菌属，命名为Streptomyces sp. Lb1。成功构建出纤维素酶表达载体，并且导入表达菌株大肠杆菌BL21(DE3)，重组菌株的产纤维素酶能力大于空载菌株。【结论】通过基因工程技术成功克隆出产纤维素酶基因，从而表达纤维素酶，为今后利用微生物降解纤维素的大规模应用提供参考。

Abstract:

[Background] Cellulose is abundant in the nature, but difficult for natural cellulase to degrade, which is a barrier to the extensive application of cellulose resources. In recent years, the degradation of cellulose by microorganisms has become a hot research topic. [Objective] A strain of actinomycete Lb1 with cellulose degradation ability was screened and isolated. The key cellulase producing gene 5676 was determined by whole genome sequencing, and the gene 5676 was cloned and transformed to be expressed in Escherichia coli. [Methods] The cellulose producing gene was connected to the expression plasmid and transferred into the expression strain by genetic engineering technology to investigate its ability to degrade cellulose. [Results] 16S rRNA gene of the strain Lb1 was sequenced, which was determined that the strain Lb1 belonged to genus Streptomyces and was named Streptomyces sp. Lb1. The expression vector of cellulose producing gene was successfully constructed, and the expression strain Escherichia coli BL21(DE3) was introduced, and its cellulase production capacity was higher than that of the wild-type strain. [Conclusion] Cellulase gene was successfully cloned and produced by genetic engineering technology to express cellulase, providing reference for large-scale application of microorganisms to degrade cellulose in future.