(76a) Material Balance for Leading Pretreatment Processes Including Sugar Conversion Using Switchgrass as Feedstock

Pretreatment and enzymatic hydrolysis are two of the three important steps to convert switchgrass to biofuels. In Consortium for Applied Fundamentals and Innovation (CAFI), several leading pretreatment technologies including Soaking in Aqueous Ammonia (SAA), Dilute Acid, Ammonia Fiber Expansion (AFEX), Controlled pH and Lime are used to pretreat a common batch of switchgrass. Developing data on leading pretreatments will provide information to help industry select technologies for applications. An additional goal of this project is to understand mechanisms that influence performance and differentiate pretreatments and to identify promising paths for advancing pretreatment technologies.

Mass balances are very important to evaluate both economic and environmental impacts for a given pretreatment process. In this presentation a complete mass balance for all the above-mentioned pretreatment processes for given conditions will be evaluated. We will report liquid-solid separation on mass basis, composition analysis for both streams (glucan, xylan, arabinan and ash were determined using the NREL LAP protocol), enzymatic hydrolysis using commercial enzyme cocktail and the resultant sugar yield (at 1% glucan loading) of the pretreated switchgrass will be reported. All the hydrolysis experiments will be performed at 100 ml reaction volume in a baffled shake flask in duplicate and monomeric sugars will be analyzed using HPLC.