Statistical Modelling of Enzymatic Hydrolysis of Banana Peels for Bioethanol Production

Abstract

This study investigated the use of banana peel (BP) for bioethanol production and the optimisation of the process parameters. Characterization of BP was done by Fourier Transform Infrared Spectroscopy (FTIR) and proximate analysis. Aspergillus niger isolated from infected cassava tubers was used for the hydrolysis of BP in a separate hydrolysis and fermentation process (SHF). Industrial Saccharomyces cerevisiae was used for the fermentation of the hydrolytes. Statistically significant quadratic regression models (p = .05) were developed for reducing sugars and bioethanol yields prediction.  Optimal condition values for the processes parameters were established by response surface methods (RSM). The FTIR results showed that BP had strong peaks for alcohols, phenols and carboxylic acids functional groups. The proximate analysis revealed that BP contains cellulose (65.5%), fibre (15.4%) and protein (6.0%) majorly. The optimum conditions for reducing sugar yields from the hydrolysis process were the temperature of 34ºC, pH of 6.5 and a period of 5 days with a yield of 122 mg/ml. While the optimum conditions for bioethanol yield from the fermentation process were the temperature of 34ºC, pH of 6.0 and a period of 5 days with a yield of 8.1% volume weight. This works shows that the optimisation of hydrolysis and fermentation processes parameters respectively improve their yields and also Aspergillus niger isolated from rotten cassava is effective in the hydrolysis of BP for bioethanol production.