Bioethanol production from Ipomoea carnea biomass using a potential hybrid yeast strain

The paper deals with the exploitation of Ipomoea carnea as a feedstock for the production of bioethanol. Dilute acid pretreatment under optimum conditions (3%H2SO4, 120 °C for 45 min) produced 17.68 g L(-1) sugars along with 1.02 g L(-1) phenolics and 1.13 g L(-1) furans. A combination of overliming and activated charcoal adsorption facilitated the removal of 91.9% furans and 94.7% phenolics from acid hydrolysate. The pretreated biomass was further treated with a mixture of sodium sulphite and sodium chlorite and, a maximum lignin removal of 81.6% was achieved. The enzymatic saccharification of delignified biomass resulted in 79.4% saccharification with a corresponding sugar yield of 753.21 mg g(-1). Equal volume of enzymatic hydrolysate and acid hydrolysate were mixed and used for fermentation with a hybrid yeast strain RPRT90. Fermentation of mixed detoxified hydrolysate at 30 °C for 28 h produced ethanol with a yield of 0.461 g g(-1). A comparable ethanol yield (0.414 g g(-1)) was achieved using a mixture of enzymatic hydrolysate and undetoxified acid hydrolysate. Thus, I. carnea biomass has been demonstrated to be a potential feedstock for bioethanol production, and the use of hybrid yeast may pave the way to produce bioethanol from this biomass.