Low input pretreatment of halophyte lignocellulose for high enzymatic convertibility

Abstract

The present study explores an environmentally friendly alternative for the pretreatment of halophyte lignocellulose by utilizing a novel soaking-extraction cycle. Compositional analysis of Salicornia ramosissima lignocellulose confirmed its high polysaccharide content, ranging from 41 to 55 g/100 g dry matter of halophyte lignocellulose. The soaking-extraction process, enriched with natural plant derived solvent (NPDS), functioned as a natural catalyst, significantly enhancing enzymatic saccharification. A double soaking-extraction cycle resulted in a 90 % hydrolysis yield and an significant 64 g of released sugars/L of hydrolysate, surpassing conventional methods. Nearly 50 % of lignin and 60 % of hemicellulose were removed, effectively reducing the lignin barrier and improving enzyme accessibility. In addition to pretreatment optimization, this study evaluated natural alternatives to synthetic buffers for enzymatic saccharification. Halophyte juice and its variants demonstrated promising potential as buffer alternatives, with juice slurry achieving a hydrolysis yield comparable to synthetic acetate buffer, yielding 37 g of released sugars/L with slurry and 42 g/L with acetate buffer, respectively. Overall, this study introduces a cost-effective and circular approach for halophyte-based biorefineries by integrating a dual-function soaking-extraction cycle that enables both bioactive compound extraction and lignocellulose pretreatment. The findings highlight significant potential for industrial applications, reducing reliance on hazardous chemicals and energy-intensive methods.