Bioconversion of Sargassum wightii to ethanol via consolidated bioprocessing using Lachnoclostridium phytofermentans KSM 1203

Contemporary studies suggest that macroalgal biomass is an attractive and alternate source for ethanol pro-duction to replace fossil fuel. Sargassum wightii, a brown macroalgae, rich in cellulose is suitable for bioethanol production. This investigation focused on the pretreatment, enzyme saccharification and fermentation for bio-ethanol production through consolidated bioprocessing (CBP) using Lachnoclostridium phytofermentans KSM 1203 isolate. The cellulose extraction from S. wightii biomass and essential medium components for L. phytofermentans KSM 1203 were optimized using Response Surface Methodology. The alkali pretreatment on S. wightii biomass removed lignin and hemicelluloses with the cellulose recovery of 82.35%. The sodium hyphochlorite treatment removes other contaminants, results the semi crystalline to amorphous cellulose structure. The optimized me-dium components for L. phytofermentans KSM 1203 was found to be pre-treated biomass 3.92 g/L, peptone 2.21 g/L, dipotassium hydrogen phosphate 1.84 g/L and sodium chloride 2.03 g/L and for the growth and co-production of cellulase activity and ethanol productivity. The maximum bioethanol yield was obtained under the optimal conditions to be 13.75 +/- 0.687 g/L for L. phytofermentans KSM 1203 from pre-treated S. wightii biomass. Hence, this investigation suggests that wild type L. phytofermentans KSM 1203 strain could be exploited for the utilization of cellulose for production ethanol in a single-step CBP procedure.

Automated summary

Contemporary studies show that macroalgae biomass, specifically Sargassum wightii, rich in cellulose, can be a promising source for ethanol production. This investigation focuses on the optimization of cellulose extraction and medium components for Lachnoclostridium phytofermentans KSM 1203 for bioethanol production through consolidated bioprocessing. The alkali pretreatment and sodium hypochlorite treatment were found to effectively remove lignin and hemicelluloses, resulting in the optimal conditions for ethanol yield of 13.75 g/L.