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

The utilization of renewable, non–edible biomass for synthesis of valuable bio–products, such as bio–fuels, 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 modified microorganisms, have gained attention and mainly involve 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 artificially produced 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 manufacture of a range of bio–products, such as amino acids, carboxylic acids, carotenoids, enzymes, vitamins, plant natural products, biogas, and other biofuels. Furthermore, the implementation of metabolic engineering techniques enhances the speed, concentration, and efficiency of commercially important substances by modifying the carbon–energy balance and eliminating an undesired ATP sink, metabolism, physiology, and stress response. Industrial biotechnology is experiencing rapid growth due to engineered MCFs for production of several bio–commodities. 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.