The mixed culture fermentation for carboxylic acid production
using BSG as the feedstock was investigated in this study. Lactic
acid was the dominant component in both acidic and alkaline
conditions and detected at the highest concentrations of 9.2 and
6.7 g L1
, respectively. However, under the neutral condition,
produced ethanol and lactic acid were quickly consumed along
with the accumulation of VFAs. Ethanol addition enhanced valeric
acid and caproic acid production, while lactic acid addition
enhanced propionic acid and butyric acid production. Further
research is needed for a better understanding of longer chain VFAs
production regulated by addition of electron donors, such as the
role of lactic acid on chain elongation and the corresponding
microbial community succession.