Enhanced hydrolysis of hydrothermally and autohydrolytically treated sugarcane bagasse and understanding the structural changes leading to improved saccharification

The enzymatic mixture containing Novozyme Cellic CTec2 spiked with xylanase derived from Thermomyces lanuginosus (1000 U xylanase per g of substrate) resulted in enhanced saccharification of native, hydrothermally and autohydrolytically pretreated sugarcane bagasse when compared to the benchmark Cellic CTec2. Hydrothermally pretreated bagasse upon hydrolysis with the enzymatic mixture yielded considerably higher levels of sugars as compared to benchmark Cellic CTec2, resulting in saccharification efficiencies of 85.7, 77.8 and 78.9% at 10, 15 and 20% (weight per volume) substrate loadings, respectively. Autohydrolysed and native sugarcane bagasse samples had lower saccharification yields, although xylanase addition to the benchmark cocktail still was beneficial. Chemical compositional analysis and detailed morphological examination of the substrates after pretreatments as well as the enzymatic hydrolysis reactions employing confocal laser scanning microscopy (CLSM), field emission scanning electron microscopy (FESEM), X-Ray diffraction (XRD) and solid state nuclear magnetic resonance (ssNMR) provided fundamental insights into the structural changes during deconstruction and shed light on how such changes affected the biomass enzyme hydrolysis.