Bio-production of ethanol and biomass from wood particles and sawdust using conventional yeast

The enzymatic hydrolysis of wood particles and sawdust (waste) and fermentation of resultant sugar to produce bio-ethanol is both economical and efficient. Sawdust and wood particles contains high amount of cellulose which needs to be broken down to simple sugar (glucose) and fermented to produce ethanol. Trichoderma viride with high enzymatic (cellulase) activity was used to hydrolyse the processed wood particles and sawdust for 5 to 7 days after which the presence of reducing sugar was determined using Fehling's and Anthrone method. The determined sugar (%) of 6.87±0.25 was optimized to 23.90±0.18 by adding commercial sugar. After optimization, the hydrolysate was inoculated with Saccharomyces cerevisiae isolated from palm wine and left to ferment for 7 days. During the fermentation, changes in physicochemical properties such as temperature, pH, titratable acidity, sugar content, specific gravity, biomass and ethanol yield were monitored. The temperature fluctuated between 29 oC and 30 oC with pH decreasing from 5.8 to 4.1, generating a biomass yield of 1.98±0.21 g/L. The sugar content (%) reduced from 23.90±0.18 to 3.83±0.32 and 10.16±0.12 ethanol (%) was obtained at the end of the fermentation. Therefore, it is clearly evident that wood particles and sawdust are potential substrates for the production of ethanol, and extending fermentation days could lead to a higher ethanol yield.