Industrial–scale production of various bio–commodities by engineered microbial cell factories: Strategies of engineering in microbial robustness

Abstract

The utilization of renewable, non–edible biomass for synthesis of valuable bio–products including bio–fuels, bio-chemicals and bio–polymeric materials, in an environmentally sustainable manner is crucial for addressing the urgent environmental challenges caused by our substantial dependence on fossil fuel resources. In this context, engineered microbial cell factories (MCFs), which are the modified microorganisms, have gained attention and provide biosynthetically optimized pathways for the production of desired bio–commodities using renewable carbon sources. Biosynthetic routes for the production of such bio–commodities can be categorized into three groups based on the chosen microbial host for genetic modification: native, non–native, and artificial pathways. Engineered MCFs are increasingly essential in the pharmaceutical, food, and bio–chemical industries and are being developed to address the growing world population and socioeconomic crisis. Mainly, microorganisms have been utilized in the manufacturing of a range of bio–products including amino acids, carboxylic acids, carotenoids, enzymes, vitamins, plant natural products, biogas, and other biofuels. Furthermore, the implementation of advanced metabolic engineering and synthetic biology tools & techniques enhances the speed, concentration, and efficiency of commercially important substances by modifying the metabolism, carbon–energy balance and eliminating an undesired ATP sink, physiology, and stress response. All these has resulted in rapid growth of industrial biotechnology for production of several bio–commodities. Further, the scale and numbers of bio–commodities is increasing with time. This review summarizes the design of MFCs, selection of microbial strains, metabolic pathways, engineered MCFs for industrial–scale applications, strategies for engineering microbial robustness, commercial restrictions, and their future prospects.