BIOCONVERSION OF ORANGE PEEL WASTE BY ESCHERICHIA COLI AND SACCHAROMYCES CEREVISIAE TO ETHANOL

An alternative energy sources using the sweet orange (Citrus sinensis (L.) waste as the feedstock was investigated; this is an approach to environmental protection. The extraction of pectin from sweet orange peel waste (pith) and the production of ethanol from the resultant liquid pectin with the aid of Escherichia coli (E. coli) and Saccharomyces cerevisiae (yeast) were carried out. Dried pith was separated using various particle sizes ranging from 0.075, 0.5, 1.0 and 5 mm. It was observed that pith with a particle size of 1.0 mm produced a larger volume of pectin while the pith with a particle size of 0.075 mm produced the least volume of pectin. 1,770 ml pectin was obtained from 802 g of pith; this shows that citrus fruit (especially orange) contains a high amount of pectin. E. coli (bacteria), yeast (fungus) and a mixture of both were added to the produced pectin which was fermented to ethanol. It was however noticed that sample pectin + E. coli + yeast, and sample pectin + E. coli produced a good volume of ethanol, but sample pectin only and sample pectin + yeast did not produce ethanol. The energy content of the total produced ethanol is 1526.6 Btu which can be mixed with pure gasoline to obtain an optimum energy content that can be used to power a citrus processing plant in Nigeria. The purpose of this paper is to obtain an alternative energy source for citrus plants using the waste generated by them such as orange peel.