Modulation of cellulase stability and activity by betaine- and choline-polyol based deep eutectic solvents

Abstract

The depletion of fossil fuels and concerns over climate change have driven interest in lignocellulosic biomass (LCB) as a sustainable feedstock for biofuel production. Cellulose, the major biomacromolecular component of LCB, is efficiently converted into fermentable sugars through enzymatic hydrolysis; however, conventional pretreatment methods are energy-intensive and environmentally unfavourable. Deep eutectic solvents (DESs), particularly those derived from natural components, have emerged as green alternatives for biomass processing. For integrated single-pot bioconversion, DESs must be compatible with cellulase enzymes. In this study, the stability and activity of cellulase were evaluated in the presence of fourteen different DESs using experimental and computational approaches. The results show that choline chloride-polyol based DESs significantly enhance cellulase stability and catalytic activity, highlighting their potential as cellulase compatible media for sustainable one-pot lignocellulosic biomass conversion. Fluorescence spectroscopic analyses combined with molecular dynamics (MD) simulations revealed that cellulase adopts a compact and stable conformation while preserving its solvation shell. These findings highlight that careful selection of DESs is critical for the development of efficient DES-based biomass conversion processes.