Valorization of jatropha fruit biomass for energy applications

Valorization of Jatropha fruit biomass for

energy applications

Ahmad Marasabessy

Thesis Abstract

Our research objectives were to develop sustainable technologies of Jatropha oil extraction and Jatropha biomass fractionation within a framework of bioconversions (enzymatic and microbial processings).  Microbial extraction of oil from Jatropha kernels using whole cells of Bacillus pumilus yields 73% oil, and this is comparable to the known processes such as by using expeller or by enzymatic extraction. The bacterium facilitates oil liberation via degradation of hemicelluloses therefore the majority of Jatropha proteins were preserved in the solid phase of the extraction residues. In investigating the effect of dilute sulfuric acid pretreatment on the enzymatic digestibility of the lignocellulosic components of Jatropha fruit biomass, we found that the seed shell and the seed cake were more recalcitrant to dilute sulfuric acid pretreatments than the fruit hull. A pretreatment of the fruit hull at optimum conditions (10% solid loading, 0.9% sulfuric acid, 30 min, 178 oC) followed by neutralization and a 24-h enzymatic hydrolysis with cellulases (GC220) liberated 100% pentoses (71% yield and 29% degradation to furfural) and 83% hexoses (78% yield and 5% degradation to 5-hydroxymethylfurfural). The fruit hull hydrolyzate can be used as a substrate for Saccharomyces cerevisiae to produce ethanol in SSF process. Our economic analysis in the retrospectives showed that valorization of the fruit biomass into variuos products (oil, protein isolate, lignin, biogas, bio-oil, etc.) using the most known techniques (pretreatment, hydrolysis, fermentation, extraction, separation, anaerobic digestion, pyrolysis) could improve the economy value of this biofuel crop significantly.