Medium chain carboxylate production from cassava wastes pretreated by ensiling

Abstract

Every 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 -1 VS while the silage without CES had an MCC yield of 137 gkg -1 VS. Out of the three kinetic models that were used to predict the production of MCCs, the dual pool model gave the best prediction.

Valorization of food waste for biogas production; effect of co-ensiling with maize straw at different C/N ratios

“…The presence of lactic acid ensures that the pH of the systems are kept low to prevent clostridial fermentation which are usually not desired in a silage. An evidence of the absence of clostridial activity is the absence of butyric acid production which can lead to a higher loss in TS content [12]. In the present study, butyric acid was below detectable limit in all silages.…”

“…In addition to these mixtures, a batch consisting of only FW was also prepared and labelled S0. About 300 g of each mixture was put into airtight bags and sealed under vacuum as previously described [12]. The samples were stored at ambient temperature for 210 days.…”

Medium-chain carboxylates production from plant waste: kinetic study and effect of an enriched microbiome

“…During ensiling, lactate and ethanol are formed that could be used as electron donors in subsequent MCC production [ 8 ], thus avoiding the need to add them to the process. Moreover, ensiling ensures year-round substrate availability and consistent quality, and serves as a pre-treatment technique [ 14 ].…”