Utilization of co-products from corn ethanol industry in a biorefinery context: a review on the biotechnological potential of thin stillage

The two largest producers of ethanol fuel in the world are the United States and Brazil. Albeit Brazil made history with its strong sugarcane-to-ethanol industry, the country is currently expanding corn-to-ethanol facilities, with the additional possibility to adapt sugarcane ethanol plants into sugarcane plus corn ethanol plants. The state-of-art in corn-to-ethanol production relies on the dry-milling process, which has been key to the development of the ethanol industry in the United States in the last decades. Within this process, some co-products are generated, which are mainly marketed as animal feed. An important intermediary coproduct generated is thin stillage, which has been thoroughly evaluated in recent biotechnological processes to produce liquid and gaseous fuels and a variety of bioproducts. In this sense, this review aimed to critically analyze the current research on thin stillage applications, emphasizing the applicability as a platform for the growth of different microorganisms and as a medium for anaerobic digestion. Thus, an outlook for the development of technologies within the Brazilian energy and biotechnological scenarios is provided, giving insights for future research work.