Designing microbial cellulases using genetic engineering approach: A promising strategy towards zero-waste cellulosic biorefinery

Cellulosic biorefinery is a promising route towards zero-waste environment and sustainable future via the utilization of industrially significant protein i.e., “cellulases”. Despite the advantage, high production costs and low productivity impedes its commercialization. However, to address the same on-site production strategies have been implemented to enhance its production. Additionally, genetic engineering approaches have be used and has allowed to engineer microbes with improved cellulases production abilities. Thus, considering the tremendous potential of cellulases, the current review provides an insight into its structure, production strategies, media optimization along with various factors that impact its production. Further, the review highlights various genetic engineering-based approaches that have been used to increase cellulase production such as heterologous expression, RNA interference (RNAi) technology, CRISPR-Cas9-based technologies etc. Lastly, its applications in various biotechnological sectors, limitations and prospects has been discussed to gain futuristic insight into zero-waste cellulosic biorefinery. [Display omitted] •Extensive applications of cellulases in cellulosic biorefinery generate zero-waste.•Metagenomics and its role in augmenting cellulases expression.•Genetic engineering its role in rational designing and fine-tuning of cellulases.•Genetically modified cellulases and its applications in various domains.