Characterization and detoxification of enzyme hydrolysates derived from dilute ammonia pretreated sorghum and energycane bagasse for syrup production

In this study, dilute ammonia pretreated sorghum (Sorghum bicolor) and high fiber sugarcane bagasse also known as energycane (Ho 02-113) bagasse were enzymatically hydrolyzed with Spezyme^® CP, a cellulase and Novozyme 188, a β-glucosidase. The enzymatic hydrolysate liquor was analyzed for monomeric sugars, organic acids, furaldehydes and phenolic acids by High Performance Liquid Chromatography (HPLC) - Diode Array Detector (DAD) method, developed for simultaneous and direct detection of EHL components and HPLC-Refractive Index Detector (RID) method. Detoxification strategies involving solid phase extraction (SPE), ionic liquid liquid-liquid extraction (LLE), ion-exchange resins, activated charcoal and molecular sieve adsorption and calcium salt experiments for minimizing degradation products while retaining monomeric sugars were evaluated. Ionic liquid LLE and ion-exchange resin detoxification strategies were successful by avoiding large sugar losses while removing non-sugar components. Optimized detoxification strategies were applied prior to converting the bagasse enzymatic hydrolysates to lignocellulosic C6 and C5 syrup feedstock for biofuels and chemicals.