Akponah E., Akpomie O. O. and Ubogu M
The capability of local strains of Zymomonas mobilis and Saccharomyces cerevisiae isolated from rafia palm (Elaesis guineesi) sap to produce ethanol from cassava waste water was investigated. Maximum ethanol produced after 48h period of fermentation by Zymomonas mobilis was 15.0 and16.5(% v/wt) in acid and enzyme hydrolysates respectively.In case of Saccharomyces cerevisiae 2.9 and 2.84(%v/wt) ethanol were produced in acid and enzyme hydrolysates respectively. In the course of fermentation, pH of acid hydrolysates that were seeded with Zymomonas mobilis and Saccharomyces cerevisiae dropped from 5.5 to 4.41 and 5.5 to 4.9 respectively. In enzyme hydrolysates that were fermented with Zymomonas mobilis and Saccharomyces cerevisiae pH reduced gradually from 5.5 to 4.46 and 5.5 to 5.1 respectively as fermentation duration increased from 0h to 48h. Also, sugar concentration reduced from 63.94 to 30.09 (mg/g) and 63.94 to 9.40 (mg/g) in acid hydrolysates that were fermented by Zymomonas mobilis and Saccharomyces cerevisiae respectively. The sugar concentration of enzyme hydrolystes fermented by Zymomonas mobilis and Saccharomyces cerevisiae were 20.08 and 5.28 (mg/g) respectively at the end of fermentation duration. The study demonstrates the suitability of indigenous Z.mobilis and S. cerevisiae obtained from the sap of raffia palm for the production of ethanol. Therefore, saucing and harnessing the potentials of these organisms would greatly minimize ethanol production cost in our locality – the Niger Delta region of Nigeria.
