InvestigatingJatrophaprunings as a feedstock for producing fermentable sugars and chemical treatment for process optimization

Abstract

Jatropha curcas has been considered as a material of choice in India for the production of bio-diesel and a very large area has been planted in India. For better growth, Jatropha plants need extensive pruning once a year, and the pruning of a healthy two year old plant on an average gives about 4–6 kg of lignocellulosic material (LCM). Jatropha prunings can be available in significant amount on annual basis. These prunings have no other use and this material has potential to be an economical and suitable LCM for conversion to fermentable sugars, as these contain considerable amount of holocellulose. In this study, acid pretreatment of Jatropha pruning was carried out using dilute sulfuric acid. A wide range of variables, i.e., acid concentrations from 2.50% to 10.0%, temperature from 120 to 180 °C, and reaction time of 5–45 min were studied. Three response factors, namely, maximum xylose release, minimum inhibitors, and maximum enzymatic digestibility, were optimized by application Taguchi design. Pretreatment efficiency was determined by enzymatic saccharification and physico-chemical properties of both native and pretreated biomass analyzed using scanning electron microscopy and Fourier transform infrared spectroscopy. This study provides insights into the intricacies involved in conversion of this biomass to fermentable sugars. These studies indicate that Jatropha prunings can be converted economically into ethanol and can provide additional support to Jatropha based bio-diesel programme.