Utilization of non-concentrated banana pseudostem sap waste for converting to bioethanol: In vitro and in silico evidence

Abstract

The abundantly available waste banana pseudostem fibers have attracted the paper and textile industries, however the stem-sap extracted during fiber processing remains underutilized. Although this sap comprising cellulosic sugars holds potential as a feedstock, its commercial viability in the renewable energy sector remains a challenge. Our study delves into this untapped resource by mechanically extracting sap from banana pseudostems and enhancing its reducing sugar content to approximately 35.5 g/L through acid hydrolysis and detoxification without concentrating the sap. Using separate batch fermentations with pentose and hexose fermenting strains such as Pichia stipitis NCIM 3499 and Saccharomyces cerevisiae ATCC 2601, we achieved bioethanol production efficiencies of 67.5 % and 70.03 %, respectively. Yield and cost analyses confirmed the feasibility of this approach for industrial application in low-economy settings. Furthermore, gene-interaction network and functional enrichment analysis identified 63 key genes involved in carbohydrate metabolism and ethanol conversion pathways within the fermenting organisms. Among these, the PGK1 gene and its direct interactors emerged as promising targets for future biotechnological enhancements aimed at boosting bioethanol production. This study not only underscores the renewable energy potential of unconcentrated banana pseudostem sap but also paves the way for innovative genetic interventions to optimize bioethanol yields.