Biomanufacturing of Inositol from Corn Stover with Biological Pretreatment by an In Vitro Synthetic Biology Platform

In this research, corn stover was pretreated by the white-rot fungus Trametes versicolor via solid-state fermentation. Nine primary factors influencing solid-state fermentation were examined through single-factor optimization. The average laccase-specific activity rose from 68.184 to 83.098 U/g, resulting in a 21.87% improvement in fermentation efficiency. Post-solid-state fermentation, steam explosion was employed to remove hemicellulose, aiding subsequent enzymatic degradation. The degradation ratio of lignin and other components reached 45.90% after the biological pretreatment and steam explosion. At the same time, the cellulose content in the resulting solid substrate increased from 38.03 to 64.71%. Subsequently, five heterologous thermostable enzymes were combined with cellulase to process the cellulose in a "one-pot method." After optimization of reaction conditions, this in vitro synthetic multienzyme catalytic system was capable of producing 4.596 g of inositol per 10 g of pretreated corn stalks. Based on the degradation products of cellulase, the final yield of inositol in the multienzyme cascades reached 89.42% of the theoretical yield. This study demonstrated the feasibility of converting natural raw materials to value-added chemicals using biological methods.