Bioethanol production from fruit peels using simultaneous saccharification and fermentation

Abstract

As the world’s energy supply is depleting, there is an increasing interest in alternative source of energy. Bioethanol production through fermentation provides an economical competitive source of energy. Chikku peels and banana peels leave a sizeable amount of residues after processing. Such residues are rich in carbohydrates, crude and sugar residues. In the present work, bioethanol has been produced and optimized from two biowastes; chikku peels and banana peels by simultaneous saccharification and fermentation using cellulase and co-cultures of Saccharomyces cerevisiae and Aspergillus niger. Pulverized chikku peels and banana peels in the ratio of 4:6 (after steam treatment) were used as substrate for bioethanol production. Temperature of 30°C, inoculum size of S. cerevisiae and A. niger 6 % (v/v), 4 % (v/v) with incubation period of 48 h and agitation for the first 24 h were found to be best for bioethanol production. The pretreated biomass after enzymatic saccharification containing 66 gL–1 reducing sugars was fermented under optimized conditions resulting in bioethanol production, yield and fermentation efficiency of 26.59 gL–1, 0.402 gg-1 and 78.99 %, respectively. This research work may establish that both chikku peels and banana peels which have been very little exploited commercially for industrial applications and are poorly disposed off can be effectively used for bioethanol production through the process of simultaneous saccharification and fermentation. The results in this paper are very encouraging and can be utilized for scaling up of the process to a pilot scale or commercial fermenter level thereby, making the process more cost effective along with contribution in waste management.