Cellulases are well known for their various industrial applications. They are naturally produced by different species of bacteria and fungi. Fermentation process of cellulase producers has limitation due to the high substrate cost required for cellulase induction and challenges to maintain the suitable condition for the respective cellulase production. Recombinant cellulase production could be the potential solution to these problems. In the current study, we investigated recombinant cellulase expression in Escherichia coli using cellulase gene from Bacillus subtilis. Extracellular cellulase production from B. subtilis strain was first confirmed on CMC agar and then the cellulase gene (1500 bp) was amplified from this strain and was further cloned in pET21a expression vector. In initial experimental studies, recombinant cellulase expression was achieved in inclusion bodies through shake flask level fermentation of transformed E. coli expression host BL21DE3. Attempts were made to express this 55 KDa His tagged recombinant cellulase into soluble form by modifications in fermentation conditions. Partially purified recombinant cellulase was obtained using Ni-NTA affinity chromatography. The activity of the purified enzyme was confirmed by 3,5-dinitrosalicylic acid (DNS) qualitative assay. Soluble expression of active recombinant cellulase can be achieved by subtle alteration in the upstream process.

中文翻译：

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利用枯草芽孢杆菌（纳豆菌株）纤维素酶基因在大肠杆菌中可溶性表达重组活性纤维素酶

纤维素酶因其各种工业应用而众所周知。它们是由不同种类的细菌和真菌自然产生的。纤维素酶生产者的发酵过程受到限制，这归因于纤维素酶诱导所需的高底物成本，以及挑战为各个纤维素酶生产维持合适的条件。重组纤维素酶的生产可能是解决这些问题的潜在方法。在当前的研究中，我们使用枯草芽孢杆菌的纤维素酶基因研究了重组纤维素酶在大肠杆菌中的表达。首先在CMC琼脂上确认枯草芽孢杆菌菌株产生的细胞外纤维素酶，然后从该菌株中扩增出纤维素酶基因（1500 bp），并进一步克隆到pET21a表达载体中。在最初的实验研究中，通过摇瓶水平转化的大肠杆菌表达宿主BL21DE3的摇动，在包涵体中实现了重组纤维素酶的表达。尝试通过发酵条件的修饰将该55 KDa His标记的重组纤维素酶表达为可溶形式。使用Ni-NTA亲和层析获得部分纯化的重组纤维素酶。通过3，5-二硝基水杨酸（DNS）定性测定证实了纯化的酶的活性。活性重组纤维素酶的可溶性表达可以通过上游过程中的细微改变来实现。使用Ni-NTA亲和层析获得部分纯化的重组纤维素酶。通过3，5-二硝基水杨酸（DNS）定性测定证实了纯化的酶的活性。活性重组纤维素酶的可溶性表达可以通过上游过程中的细微改变来实现。使用Ni-NTA亲和层析获得部分纯化的重组纤维素酶。通过3，5-二硝基水杨酸（DNS）定性测定证实了纯化的酶的活性。活性重组纤维素酶的可溶性表达可以通过上游过程中的细微改变来实现。