European Journal of Biotechnology and Bioscience

author(s)
Kuntala Das, Premsunder Ghosh, Apurba Dey, Amit Ganguly, Subhabrata Das, Pradip Kumar Chatterjee

abstract
The study investigates the production of xylose by acid hydrolysis from water hyacinth (Eichhornia crassipes) and its subsequent bioconversion into xylitol. Lignin derived phenolic compound is inhibitory to the xylitol production process. Hence pretreatment of water hyacinth was first performed with sodium hydroxide to remove phenolics derived from lignin. Response surface methodology (RSM) was incorporated to evaluate the combined effect of independent factors affecting the pre-treatment process to remove lignin. The factors affecting the process are concentration of sodium hydroxide solution (2%, 3% and 4% w/v), soaking time (2-4 h), agitation speed (100 rpm, 130 rpm, 160 rpm), treatment time (7-15 min) and operating treatment temperature (30-70 oC) respectively. Acid hydrolysis was performed by autoclaving at 121 oC for 15 min with the pre-treated water hyacinth biomass, which released maximum phenolics (3524.16 mg/l) in the pre- treatment hydrolysate. 34.22 g/l of xylitol was produced by Pichia stipitis at 48 h of fermentation, with a yield of 0.645g xylitol/g xylose.