Monday, April 29, 2013
Exhibit Hall
Classical cellulose decomposition to sugars occurs enzymatically through the synergistic action of at least three types of enzymes, which are endoglucanases, cellobiohydrolases and β-glucosidases. The discovery of oxidative cleavage of cellulose by enzymes classified as GH61 but which in reality are lytic polysaccharide monooxygenases (LPMO) demonstrated the ability to boost the cellulose conversion of pretreated lignocellulosic biomass. The objective of this work was to evaluate the effect of LPMO in a commercial enzyme mix (Cellic CTec2) upon overall hydrolysis and the formation of oxidized products such as gluconic acid. Hydrothermally pretreated wheat straw, corn stover and sugar cane bagasse was tested as substrate. Sugarcane bagasse was also pretreated by alkaline and organosolv pretreatment resulting in different lignin to cellulose and hemicellulose ratios. Around 0.5% of the converted cellulose ended up as gluconic acid using Cellic CTec2 on the different biomasses. The use of these substrates with varying lignin content showed a correlation to the level of gluconic acid produced. As enzymatic hydrolysis is a multifactor phenomenon, the study of the enzyme system were complemented with lignin adsorption studies to the different sugar can lignins. Subsequent characterization of the physical and chemical properties of the isolated structures was done by microscopy and ATR-IR spectrometry. The lignin isolates interactions with cellulases during enzymatic hydrolysis were investigated.