Fungal pretreatment and acid post-treatment for fractionation and biovalorization of palm biomass wastes into fungal oil, bioethanol, and lactic acid

This research aimed to develop prototype for fully utilizing palm empty fruit brunches (EFB) for production of sugars and biofuels. EFB was biologically pretreated using oleaginous fungus and post-treated using mild acid. This process can remove lignin and fractionate hemicellulose from cellulose pulp, which was confirmed by chemical composition, functional groups, and crystallinity changes. The cellulose pulp was used for ethanol production via simultaneous saccharification and fermentation (SSF). To increase initial sugar concentration prior to ethanol production, repeated-prehydrolysis (RPH) was attempted. The RPH for four cycles gave the maximum sugars of 60.9 +/- 1.9 g/L, and the subsequent SSF gave the highest ethanol of 35.2 +/- 2.7 g/L with an ethanol yield of 0.40 g/g-sugar. Moreover, during fungal pretreatment the fungus also accumulated lipids with high potential as biodiesel feedstocks, and the hemicellulose hydrolysate obtained after acid post-treatment could be used for lactic acid fermentation. This study has shown a practical biorefinery roadmap for bio-valorization of palm biomass wastes into multiple bioproducts, which may greatly contribute to Bio-Circular-Green (BCG) economy.