Bioconversion of lignocellulosic fraction of water-hyacinth (Eichhornia crassipes) hemicellulose acid hydrolysate to ethanol by Pichia stipitis

Fermentation of acid hydrolysate of water-hyacinth (Eichhornia crassipes), a free floating aquatic plant has been investigated for ethanol production. The dilute acid treatment has been applied to utilize the maximum hemicellulosic content of the water-hyacinth. The goal of this work was to investigate, both experimentally and theoretically using mathematical tools, a fermentative system utilizing water-hyacinth (Eichhornia crassipes) hemicellulose acid hydrolysate as a substrate for ethanol production using Pichia stipitis. It was found that 72.83% of xylose was converted to ethanol with a yield of 0.425 g_p/g_s and productivity of 0.176 g_p/L/h. An appropriate mathematical model was developed to explain theoretically the bioconversion of this hemicellulose acid hydrolysate to ethanol and the model was tested statistically to check the validity of the model.