Recent advances in the microbial production of C4 alcohols by metabolically engineered microorganisms

Abstract

Background:The heavy global dependence on petroleum-based industries has led to serious environmental problems, including climate change and global warming. As a result, there have been calls for a paradigm shift towards the use of biorefineries, which employ natural and engineered microorganisms that can utilize various carbon sources from renewable resources as host strains for the carbon-neutral production of target products.Purpose and Scope: C4 alcohols are versatile chemicals that can be used directly as biofuels and bulk chemicals and in the production of value-added materials such as plastics, cosmetics, and pharmaceuticals. C4 alcohols can be effectively produced by microorganisms using DCEO biotechnology (tools to design, construct, evaluate, and optimize) and metabolic engineering strategies. Summary of New Synthesis and Conclusions:In this review, we summarize the production strategies and various synthetic tools available for the production of C4 alcohols and discuss the potential development of microbial cell factories, including the optimization of fermentation processes, that offer cost competitiveness and potential industrial commercialization.

Recent advances in fermentative production of C4 diols and their chemo-catalytic upgrading to high-value chemicals

“…The diols, especially 2,3-, 1,4-, and 1,3-BDO, have received renewed interest owing to their vast derivative potentials due to the existence of two OH groups at different positions. These favorable features are exploited in various industrial sectors for manufacturing fuels, solvents, monomers, and pharmaceutical precursors from BDOs [14,15,21]. The environmentally benign green products have rekindled significant interest in sustainable low-carbon manufacturing technologies.…”

“…Dedicated research efforts have been made to design microbial cell factories in producing BDOs at high titers, yield, and productivity (TYP). Fermentative production of 2,3-BDO started > 100 years ago with many literature reports, while only a handful of studies are available on the production of 1,3-BDO and 1,4-BDO via microbial route [10,15,22,23].…”

“…However, integrated bio-and chemo-catalytic approaches are yet to be commercialized for producing valuable products, except few attempts by some research groups [13,[137][138][139]. Even in current times, the market share of fermentative C4 diols is quite less and limited to only a few of them, while most of them are under development due to inefficient bioprocess with prohibitive production prices [15]. However, there are four bio-based marketable technologies for 2,3-BDO and one commercial technology by Genomatica for 1,3-BDO and 1,4-BDO [45,140].…”

“…On the other hand, 1,3-BDO and 1,4-BDO are the non-natural metabolites, where 1,4-BDO is commercially produced via the biological route, while titer of 1,3-BDO stays under 30 g/L, and TYP metrics are far from industrial manufacturing. Currently, Genomatica, a US-based company, is the active player in commercial bio-based production of 1,4-BDO [15]. LanzaTech and GS Caltex, an oil refinery company in South Korea, are producing 2,3-BDO at industrial scale [140].…”

“…Butanediols represent four structural isomers of straight-chain C4 diols (Table 1). Currently, BDOs are produced by the petrochemical route [14,15]. For instance, four technologies are used to produce 1,4-BDO from acetylene, propylene, butadiene, and butane [16][17][18].…”