Dilute Acid Pretreatment of Farm-Waste Cultured Algae and Its Effect On Enzymatic Hydrolysis of Cellulose

The objectives of this study are: (1) to determine the optimal conditions of hydrolysis of farm-waste cultured algal biomass using dilute acid method, and (2) to investigate the effects and correlation of algal hydrolysate and enzyme loadings on enzymatic hydrolysis of pretreated lingocellulose. We statistically studied the effect of reaction conditions of acid concentration, temperature, and reaction time on the accumulation of total sugar released in dilute sulfuric acid treatment of AD effluent cultured algal biomass. Based on the regression model, the optimal conditions for sugar accumulation were 4% H₂SO₄ (w/w), 116°C reaction temperature and 30 min reaction time. Under these conditions, sugar concentration reached 28.18% of total biomass (DW), which is 99% of total sugar in algal biomass. Furthermore, the algal hydrolysate was applied as medium in the enzymatic hydrolysis of alkaline pretreated AD fiber, it demonstrated a significant increase (P < 0.001) in glucose yield compared to the control of hydrolyses using citrate buffer (conventionally employed in enzymatic hydrolysis) and deionized water. This study presented a potential pathway of integrated utilization of both liquid (algal cultivation) and solid (enzymatic hydrolysis) wastes from aerobically digested dairy manure for biofuels production. Implementation of such process will provide a mutually beneficial solution for agricultural operations, bioenergy production, and environmental protection.