Green processing of tropical banagrass into biofuel and biobased products: An innovative biorefinery approach

Banagrass (Pennisetum purpureum) approximately 4 months old was hand-harvested and shredded. Half of the sample was dewatered using a screw-press, whereby the extracted juice was used for cultivating an edible fungus, Rhizopus microsporus, for aquaculture feed supplementation. The remaining biomass was divided into four separate streams: (1) wet, juiced; (2) dry, juiced; (3) wet, unjuiced; and (4) dry, unjuiced. Each stream was pretreated with dilute sulfuric acid and compared on the basis of sugar release at varying acid concentrations, temperatures, and residence times. Wet, juiced banagrass released the most soluble sugars (theoretical xylose and ∼85% glucose). Ultrasonication (20 kHz) was applied to further increase monomeric sugar release but demonstrated little improvement on total sugar yields. Fungal biomass generated from banagrass juice exhibited potential as a fungal-protein production medium producing 1.16 ± 0.34 g biomass increase/g initial biomass.