A novel biorefinery concept of utilising waste bread as a sole nutrient source for the production of a nutrient
rich feedstock for the fermentative succinic acid production by Actinobacillus succinogenes has been
developed. Waste bread was used in the solid-state fermentations of Aspergillus awamori and Aspergillus
oryzae that produce enzyme complexes rich in amylolytic and proteolytic enzymes, respectively. The
resulting fermentation solids were added directly to a bread suspension to generate a hydrolysate containing
over 100 g/L glucose and 490 mg/L free amino nitrogen (FAN). A first-order kinetic model was
used to describe the effect of initial bread mass ratio on glucose and FAN profiles. The bread hydrolysate
was used as the sole feedstock for A. succinogenes fermentations, which led to the production of 47.3 g/L
succinic acid with a yield and productivity of 1.16 g SA/g glucose and 1.12 g/L h. This corresponds to an
overall yield of 0.55 g succinic acid per g bread. This is the highest succinic acid yield compared from
other food waste-derived media reported to date. The proposed process could be potentially utilised to
transform no-value food waste into succinic acid, one of the future platform chemicals of a sustainable
chemical industry.