BIOETHANOL PRODUCTION FROM Annona muricata USING Saccharomyces cerevisae

ABSTRACT

Bioethanol is a source of renewable energy, which is ecofriendly and non-toxic to the environment. It is produced through the microbial fermentation of carbohydrates from food crops such as corn, sugarcane and wheat. The aim of this study was to produce bioethanol from the pulp and peel of Annona muricata (soursop) through the process of fermentation, using Saccharomyces cerevisae. Fresh soursop fruits were purchased from New Benin market, Benin City, Edo State. The fruits were washed and the substrates (pulp and peel) for fermentation were prepared under aseptic conditions. The process of bioethanol production was carried out by submerged fermentation, using Saccharomyces cerevisae. The fermentation process was monitored at 28±2oC for 120hrs using the parameters of pH, temperature, presence of reducing sugar and alcohol density. The pH was determined using a digital pH meter (Roulan). The temperature, reducing sugar, alcohol density and total ethanol concentration was determined using appropriate methods. Results for pH ranged from 4.0 to 4.6 and 3.4 to 4.0 while the temperature values ranged from 24.4 to 34.1oC and 24.4 to 35.1oC for peel and pulp respectively. Results for alcohol density ranged from 5.58±2.46 to 0.11±0.002g/ml and 0.30±0.005 to 0.16±0.000g/ml for peel and pulp. The bioethanol concentration obtained were 2.0% and 5.2% respectively while the bioethanol yield obtained was 18.16ml and 32.14ml for peel and pulp respectively. This study revealed that Annona muricata pulp and peel were capable of producing bioethanol. The highest concentration of ethanol was produced from the pulp. This may be due to the high sugar content of the fruit which is found in the pulp. Furthermore, the acidic pH of both substrates were most suitable for bioethanol production. However, for large scale production, a larger inoculum size, increased sugar content and fermentation time is advised.