Production of Bio-ethanol by Enzymatic Saccharification through Response surface Method using Agro-waste

A major constraint in the enzymatic saccharification of biomass for ethanol production is the cost of enzymes. Production cost of enzymes may be brought down by multifaceted approaches which include use of cheap lignocellulosic substrates for fermentation and production of enzymes, and use of cost efficient fermentation strategies like solid state fermentation (SSF). The focus of this study, firstly different agro-waste was washed with tap water for three times. Next wheat bran was screened from different agro-wastes. Then enzymatic saccharification of pre-treated wheat bran for high yield of reducing sugar using a purified enzymatic treatment from fungal isolate Aspergillus flavus PUF5. Central Composite Design was employed to plan experiments and optimize the enzymatic saccharification of wheat bran. Experimental results show that substrate amount, fermentation time and pH of the medium were main factors governing the enzymatic saccharification of wheat bran. The Model F value of 52.73 implied the Model was significant. Model P value in this study was < 0.01, which also indicated that the model was significant. The “Pred R–Squared” of 0.8982 was in reasonable agreement with the “Adj R-squared” of 0.9668, which indicated a good fitness of the model. On the basis of medium optimization, the quadratic model predicted that the maximum amount of reducing sugar was produced (36.4 mg/g) when the substrate amount, fermentation time and pH were 5.7 g, 16 h, and pH 6.5, respectively. The fermentation of the concentrated hydrolyzate (20 gL−1) by Saccharomyces cerevesiae resulted in ethanol concentration of 7.9 gL−1.