Saccharification of Carbohydrates in Microalgal Biomass by Enzymatic Pretreatment-An Integral Approach for Bioethanol Production

Fermentation of carbohydrates to produce bioethanol is one of the pathways to produce biofuels from microalgae. This is comprised of complex and energy consuming process. Cell wall disruption and hydrolysis are two of the stages that must be carried out, since most carbohydrates are entrapped within the cell wall or intracellularly as energy storage in the form of starch. Microwave pretreatment is a pretreatment method used as it causes rapid alignment and realignment of dipoles in a polar solvent, resulting in heat generation, which can alter cell wall structures and opens up the complex cell wall structure for further action of enzymes. Then enzymatic pretreatment performed on microalgal species to disrupt and break down complex carbohydrates into simple sugars, as a prerequisite step to produce bioethanol. In the present study, effect of microwave pretreatment on microlagal biomass was studied which was further accompanied by a mixture of different inhouse enzymes (cellulase: amylase: xylanase: pectinase) for enzymatic hydrolysis of microalgae. The best conditions for microwave pretreatment included 300 watts for 60 seconds with enzymatic ratio (5: 3: 1: 1) resulting in reducing sugar yield of 122.88 mg/g of biomass. The results obtained proved the effectiveness of microwave pretreatment with enzymatic hydrolysis to enhance complex carbohydrates break down into simple sugars in bioethanol production process from microalgal biomass.