Medium chain carboxylate production from cassava wastes pretreated by ensiling

Abstract

AbstractEvery year, approximately 35 million tons of combined cassava peels (CP) and cassava wastewater (CWW) are generated from the processing of cassava in Nigeria. The improper disposal of these wastes has serious environmental consequences in the form of air and water pollution. Using these wastes for biofuel production is one way of mitigating the impact of the mass flows on the environment. However, being a lignocellulosic biomass, CP requires pretreatment before it can yield a reasonable amount of biofuel. In this study, ensiling was chosen as a method for the pretreatment of CP slurry (CPS), formed from the combination of CP and CWW, for the production of medium‐chain carboxylates (MCCs), which have been reported to be more valuable than biogas and bioethanol. Calcined egg shells (CES) were added to some of the CPS before ensiling, to enhance the formation of butyric acid. The MCCs were produced through batch fermentation of the silage. The results show that ensiling degraded the hemicellulose and cellulose content of CPS. The silage containing CES had greater loss of volatile solids, higher butyric acid content, and a higher MCCs (C6‐C8) yield of 210 gkg‐1VS while the silage without CES had an MCC yield of 137 gkg‐1VS. Out of the three kinetic models that were used to predict the production of MCCs, the dual pool model gave the best prediction.