Ethanol production by Zymomonas mobilis using natural rubber waste as a nutritional source

Abstract

Abstract The feasibility of using natural rubber serum powder (NRSP) as a nutritional source instead of yeast extract on ethanol fermentation by Zymomonas mobilis was carried out. The results showed that NRSP either as it is or hydrolyzed with pronase has the potential to be used as a nutritional source. The optimum NRSP hydrolysate and mieki concentration supporting better growth rate and biomass yield are 0.3% and 1%, respectively. Comparative kinetic studies of Z. mobilis grown on yeast extract medium (10% glucose), NRSP hydrolysate-mieki medium (10% glucose) and NRSP hydrolysate-mieki medium (10% glucose from sago starch) were studied. It was found that specific glucose uptake rate, specific ethanol production rate and ethanol yield on NRSP hydrolysate-mieki (10% glucose and 10% glucose from sago starch) are comparable to those values on yeast extract medium. The cell viability of cells grown on NRSP hydrolysate-mieki medium was also observed as being comparable to values for yeast extract medium.