Enhanced acid hydrolysis for bioethanol production from water hyacinth (Eichhornia crassipes) using fermentating yeast Candida intermedia NRRL Y-981

This study presents bioconversion of water hyacinth (Eichhornia crassipes) to bioethanol using two-sequential steps of acid hydrolysis (10% sulfuric acid) and yeast (Candida intermedia) fermentation. Maximum ethanol yield co-efficient was comparable to those obtained through enzymatic saccharification and fermentation of acid hydrolysate using fully equipped fermentor. A maximum ethanol yield (coefficient, 0.21 g g(-1); productivity, 0.010 g l(-1) h(-1)) was comparable to predicted value (0.23 g g(-1)) obtained by CCD (Central Composite Design). Two colorimetric methods (phloroglucinol and dichromate assays) were used for determination of xylose and ethanol using UV-Vis spectrophotometer. Although maximum ethanol concentration was low, an economically efficient overall process was carried out to convert a lignocellulosic biomass to bioethanol.