Efficient utilization of melon peels to produce ethanol: a step toward sustainable waste management

Cellulosic material like melon peels can be a potent source of bioethanol and it can be exploited to combat the increasing energy demands. In the current study, dried and powdered melon peel waste was hydrolyzed by dilute H2SO4 into monomeric sugars and then fermented by different yeast strains to produce bioethanol. The parameters for dilute H2SO4 hydrolysis of substrate were optimized by response surface methodology for three variable factors, i.e., X-1, acid concentration (2-6%); X-2, hydrolysis temperature (50-100 degrees C); and X3, hydrolysis time (30-60 min). The responses were reducing sugars and total sugars. According to the results of biochemical tests, 89.6 +/- 0.03 g/L was the highest reducing sugars with significant values of F (3.98), p (0.0258), and R-2 (0.7994). Maximum total sugars were recorded as 225.90 +/- 0.09 g/L having significant F, P, and R-2 values of 3.23, 0.0477, and 0.7849, respectively. The optimum conditions for maximum yield of reducing and total sugars were X-1 (6%), X-2 (50 degrees C), and X-3 (60 min). For ethanologenesis, one standard yeast Saccharomyces cerevisiae K7, while two experimental yeasts belonging to the genus Metschnikowia were used. Maximum ethanol yield (0.39 +/- 0.006 g/g) with 78.21% fermentation efficiency was estimated on the 6th day by Metschnikowia cibodasensis Y34. The findings of the study will provide an insight for converting cellulosic wastes into energy.

Automated summary

In this study, dried and powdered melon peel waste was hydrolyzed by dilute H2SO4 into monomeric sugars and then fermented by different yeast strains to produce bioethanol. The findings provide insights into converting cellulosic wastes into energy.