Harnessing Lignocellulolytic and Electrogenic Potential: Insights from Shewanella oneidensis MR-1 and Cellulomonas Strains on Lignocellulosic Biomass

Abstract

The biodegradable and renewable nature of lignocellulosic biomass (LCB) has gained significant interest in recent years. This study explores the lignocellulolytic and electrogenic potential of Shewanella oneidensis MR-1, Cellulomonas fimi ATCC 484, and Cellulomonas biazotea NBRC 12680 on LCB. Two strategies were tested: assessing strains LCB degradation ability under non-electrochemical and electrochemical conditions. Strain selection was based on literature, and bioinformatical analyses were conducted to predict CAZymes and carbohydrate degradation pathways. Cellulomonas strains have a potential to degrade LCB due to high CAZyme count and specific metabolic pathways. Strains growth capacity on LCB was evaluated by culturing without electrodes on LCB for 12 days, showing superior growth on wheat bran compared to wheat straw. Enzymatic assays indicate laccase activity in all strains, highest in C. biazotea NBRC 12680 (11.66 IU). The strains ability to form electrogenic biofilms on carbon cloth anodes polarized at +0.2 V (vs Ag/AgCl) was evaluated. The results indicate that bioanodes can function with wheat bran (max current density: 14.92 mA m−2), with voltammograms showing redox activities. Attenuated total reflection Fourier transform infrared spectroscopy shows lignin and protein degradation in both electrochemical and non-electrochemical experiments. These findings suggest potential use of these strains in electro-microbial systems with LCB.