EXTRACTION OF BIOETHANOL FROM PRETREATED SAWDUST

In this study, optimization of brix conversion of wood shavings by Saccharomyces cerevisiae was investigated. Wood shavings were collected from timber shade at Naze, Owerri Imo state. Chemical pretreatment and hydrolysis was evaluated. Brewer's yeast (Saccharomyces cerevisiae) was used as the isolate for fermentation. A five factor box behnken design was used. The effect of incubation temperature(30-40oC), inoculum size(0.85),incubation time (72-120hours), wood concentration( 10-20g), and NaOH concentration (3.5-4.5%) were studied using response surface methodology (RSM). Brix concentration was used as a response in the resulting experimental design. The statistical analysis of the constructed model developed by RSM suggested that linear effects of NaOH concentration and wood concentration were both significant (p<0.05) for biomass converted. The optimum conditions for the conversion of brix are wood concentration of 15.66g, NaOH concentration of 4.47%, inoculum size of 0.85, incubation time of 72hours and incubation temperature of 40oC. Ethanol yield obtained was 1.68-2.25%. At these conditions, the isolate used was able to convert 60.97% of the brix in the wood extract to ethanol.