8-08: The effect of wet storage on the value of corn stover as a biofuel feedstock

As lignocellulosic biofuel technology advances and commercialization is achieved, there will be increasing incentives to characterize and price feedstocks based on downstream processing requirements and potential yield. For biochemical conversion platforms, biomass storage can affect feedstock in two ways: (1) dry matter loss and altered feedstock composition, which will determine the amount of convertible sugars present and (2) the intensity of pretreatment required to optimize fuel yield.  The present research investigates wet storage of corn stover and these two effects on feedstock value. Key variables tested included the corn stover collection method, stover moisture content, storage temperature, storage duration, and oxygen level during storage. Feedstock composition before and after storage was determined by Near InfraRed (NIR) spectroscopy. The changes in dry matter and amounts of convertible sugars were quantified and analyzed for impacts on target feedstock price. Reduced –severity pretreatment and fermentation of the samples was used to characterize storage impacts on downstream processing and yield.  While structural sugar composition is a major indicator of downstream biofuel potential, inhibitors formed during storage and pretreatment can also interact to influence feedstock value and fuel yield.