Bioethanol Production from Sugarcane Bagasse: Optimization Through Response Surface Methodology and Experimental Validation

Abstract Sugarcane bagasse is byproduct of sugarcane juice processing. After juice extraction, each tonne of sugarcane produces 130 kg dry weight of bagasse. The present study attempts to produce microbial bio-ethanol using sugarcane bagasse as substrate. After size reduction and chemical pretreatment of sugarcane bagasse using 1M of NaOH 35.68% of hydrolysis was achieved. Ethanol fermentation was carried out in 250 ml Erlenmeyer flask comprising pretreated SCB (30 g/100 ml) containing beads of 6.5% calcium alginate entrapped cellulase with the supplementation of 10 g/l of yeast extract as a nitrogen source using Saccharomyces cerevisiae. After 24 hours, the fermentation broth's alcohol production began, and it reached maximum after 72 hours. The estimated alcohol concentration was 8.1%, and the productivity was 1.14 ml/l/h. The central composite design (CCD) of response surface method (RSM) was used to estimate the levels of variables pH (5.0), incubation time (72 h), inoculum size (10 ml/l), and substrate concentration (40g/100ml) and the impact of their interactions on ethanol production. The fitted model's validity was assessed, and the F-test was used to control its statistical significance. The model F value was calculated to be 92.362 which imply that the model is significant. The experimental model was validated by the laboratory results.