Efficiency of biogas production from corn bioe-thanol by-products using different inocula

Two major problems of the rapidly expanding corn bioethanol industry are the fate of the massive by-product amounts, and the high energy demand of by-product processing. Traditional by-product processing methods consist mostly of the evaporation and drying of distillery wastewater, hence they are very energy-intensive, worsening the already modest net energy balance ratio of the corn ethanol. Bioethanol byproducts have been shown to be further degradable by anaerobic digestion (AD), and hence AD represents a potential bioethanol-byproduct processing alternative. The resulting biogas can be used on-site, bettering the energy balance of the ethanol production. In this work bioethanol byproduct digestion assays have been performed under mesophilic and thermophilic conditions using four different inocula, in order to assess the effect of inoculum choice on the biomethanation efficiency. Differences as high as 130% were observed in terms of specific methane yield and ultimate methane production, when comparing the performance of the inocula.