Impact of thermal pretreatment on food waste chemical characteristics alteration during anaerobic fermentation with Saccharomyces cerevisiae inoculation: Protein vs carbohydrate

Abstract

The valorization of food waste through anaerobic fermentation (AF) is an emerging approach aligned with the circular economy framework. This study investigated the impacts of thermal pretreatment and Saccharomyces cerevisiae inoculation on the conversion of food waste, represented by cabbage (carbohydrate-rich) and chicken breast (protein-rich), into valuable volatile fatty acids (VFAs). The results demonstrated that thermal pretreatment enhanced the solubilization of complex carbohydrates, leading to a ∼122 % increase in total acetic and propionic acid production in cabbage. Conversely, while thermal pretreatment improved protein denaturation, it did not significantly enhance VFA yields from chicken breast, with around 3 % carbon conversion rate into VFA. The findings indicated that protein-rich feedstocks were less suitable for efficient AF conversion. Thermal pretreatment altered microbial populations, promoting carbohydrate-degrading bacteria in cabbage while protein-degrading bacteria dominated in meat-based feedstocks without notable efficiency improvements. The findings highlighted the potential of carbohydrate-rich feedstocks for AF, particularly regarding VFA generation, and suggest the need for further optimization in protein-rich feedstock applications.