Applying Biorefinery Concepts for Sugarcane Straw Upcycling Using Alkaline and Enzymatic Treatments to Produce Value-Added Compounds and Bioenergy

The objective of this study was to develop a sugarcane straw biorefinery that targets the valorization of glucan, hemicellulose, and lignin streams generated through sequential and integrated treatments. Complementary biocatalytic strategies include ferulic acid isolation and biotransformation into high-value compounds, such as coniferol (a molecule with broad application in chemical synthesis) using a genetically engineered Escherichia coli strain (BL21-pROB) and xylooligosaccharides (XOS) using a feruloyl esterase and xylanase chimeric enzyme (XynZ). This biorefinery scheme also considers lignin recovery for solid biofuel and lignin nanoparticle synthesis. The evaluation of integration scenarios showed that a mild-alkaline pretreatment followed by enzymatic hydrolysis with XynZ and subsequent biotransformation with BL21-pROB strain, saccharification, and fermentation steps allowed up to 85% (w/w) of sugarcane straw plant cell wall component conversion into coniferol, XOS, fermentable sugars, bioethanol, lignin nanoparticles, and solid biofuel.