Synergistic Enzyme Cocktail to Enhance Hydrolysis of Steam Exploded Wheat Straw at Pilot Scale

Multiple enzymes are required for efficient hydrolysis of lignocellulosic biomass and no wild type organism is capable of producing all enzymes in desired levels. In this study, steam explosion of wheat straw was carried out at pilot scale and a synthetic enzyme mixture (EnzMix) was developed by partially replacing the cellulase with critical dosages of commercially available accessory enzymes (β-glucosidase, xylanase and laccase) through central composite design. Highest degree of synergism (DS) was observed with β-glucosidase (1.68) followed by xylanase (1.36). Finally, benchmarking of EnzMix (Celluclast, β-glucosidase and xylanase in a protein ratio of 20.40: 38.43: 41.16, respectively) and other leading commercial enzymes was carried out. Interestingly, hydrolysis improved by 75% at 6 h and 30% at 24 h, respectively in comparison of control. By this approach, 25% reduction in enzyme dosage was observed for obtaining the same hydrolysis yield with opitimized enzyme cocktail. Thus, development of enzyme cocktail is an effective and sustainable approach for high hydrolysis efficiency

Preparation of novel catalyst composition from natural waste for biodiesel production

1054-1060This study presents preparation of a novel, cost effective and recyclable catalyst from natural waste for production of biodiesel. Novel catalyst composition has been developed using combination of seashell and eggshell in complexation with transition metal oxide TiO2 to form A-B-O type metal oxide complex, where A is alkaline metal and B is transition metal. Catalyst composition has been evaluated and a robust cost effective method for biodiesel production is proposed

Impact of Conditioning Prior to Dilute Acid Deconstruction of Biomass for the Production of Fermentable Sugars

Cost of cellulases is a major impediment in commercialization of cellulosic ethanol. To reduce the enzyme doses for the production of fermentable sugars from rice straw (RS), a series of alkali conditioning experiments were conducted prior to dilute acid (DA) pretreatment. This approach resulted in removal of a majority of extractives, ash, acetic acid, and part lignin, and thus resulted in lowering pseudolignin formation thereby increasing enzymatic hydrolysis yields. Glucan hydrolysis of 69.8%, 74.0%, and 83.5% was obtained at 10 wt % water insoluble solid (WIS) using 8 FPU enzyme/g WIS of biomass conditioned using 0.2, 0.4, and 0.5 wt % alkali prior to pretreatment, which is 14–37% higher than the control (61.0%). The overall sugar recovery in these experiments were 69.2%, 70.2%, and 68.5% at 15 wt % WIS resulting in a sugar concentration greater than 120 g/L, which in turn can produce approximately 5–6% w/v ethanol concentration in fermentation broth. It was found that this approach resulted in a decrease of the enzyme consumption vis-a-vis the conventional process by 46.4% to recover the same amount of sugars. This lowering of enzyme consumption has resulted in net savings, after taking into account the cost of alkali used in the conditioning steps