Recent perspectives on microbial and ionic liquid interactions with implications for biorefineries

In recent years, in pursuit of sustainable and green chemistry, a plethora of ionic liquids (ILs) have been formulated to serve as safe alternatives to toxic solvents for numerous applications in electrochemistry, organic synthesis, inorganic/organic transformations, catalysis etc. Nonetheless, the unique and easily tunable physico-chemical properties of these ILs have progressed their usage as reaction media in bio-catalysis. Especially in the context of lignocellulosic biomass valorization, ILs have emerged as a promis-ing choice for dissolution of biomass leading to better enzymatic digestibility due to efficient pretreatment. The present review highlights the potency of IL mediated valorization of waste feedstocks for the development of sustainable circular biorefineries. However, the usage of IL mediated biocatalysis at bench scale has been hampered by enzyme denaturation and viability loss of fermenting microbes in IL laden environments, which prevents the realization of the ultimate aim of consolidated biomass process-ing in one-pot. Though enzyme stabilization in ILs has witnessed significant improvement with various approaches, the studies for a comprehensive understanding of microbial interactions with ILs are still in an exploratory phase. The present review intends to provide elaborative insights into toxicological issues of ILs to microbial cells and their mechanism of growth inhibition, which can potentiate their pharmaceu-tical applications as anti-microbial agents as well as provide insights for designing biocompatible cat-alytic systems. Further, the adaptive mechanisms exhibited by IL-resilient microbes have been elaborately discussed. A comprehensive elucidation of the current and future directions of designing compatible IL-microbe biocatalytic systems has been encompassed, which will facilitate advancements in IL-assisted biocatalysis for sustainable production of value-added products via waste-derived biorefineries.(c) 2022 The Authors. Published by Elsevier B.V.

Automated summary

This review highlights the potential of ionic liquids (ILs) for sustainable circular biorefineries, particularly emphasizing their importance in lignocellulosic biomass valorization. However, at the laboratory scale, IL-mediated biocatalysis faces limitations such as enzyme denaturation and loss of viability for fermenting microbes. Although enzyme stabilization in ILs has improved, the understanding of microbial interactions with ILs is still exploratory.