Cellulose solvent–based pretreatment and enzymatic hydrolysis of pineapple leaf waste biomass for efficient release of glucose towards biofuel production

Leaf waste biomass of pineapple Ananas comosus can be used as the substrate for the second-generation biofuel production. The non-environmental friendly practice of pineapple leaf waste handling on the field can largely be avoided by directing the leaf waste as a feedstock for biofuels. In this study, three varieties of pineapple queen, simanchal (a local variety of India), and kew were used for the production of glucose. The leaf biomass of these pineapple varieties contained 19 to 22% extractives, 31 to 32% glucan, 17 to 22% hemicellulose, and 17 to 20% lignin. Biomass without any pre-treatment when digested with cellulase released 36 to 43% glucose, whereas glucose release percentages significantly elevated when the biomass was subjected to phosphoric acid-based cellulose solvent and organic solvent lignocellulose fractionation (COSLIF) pretreatment before hydrolysis. Herein, we found that cellulase enzyme dosages 5 filter paper unit (FPU) along with 10 international units (IU) of β-glucosidase per gram of glucan of COSLIF-pretreated leaf biomass of queen variety resulted in the generation of 84% glucose after 72 h of incubation. Assuming 100% conversion of glucose to ethanol, theoretical ethanol yield was calculated to be 212 L from 1 t dry leaf biomass.