FERMENTATION CONDITIONS IN SIMULTANEOUS SACCHARIFICATION AND FERMENTATION PROCESS FOR VOLATILE FATTY ACIDS PRODUCTION

The growing global demand for energy and climate concerns have driven the search for sustainable alternatives such as bio-based butyric acid (BA), a promising precursor for biopropane. In this study, soybean hulls—a lignocellulosic agricultural residue—were used in a simultaneous saccharification and fermentation (SSF) process for BA production using Clostridium tyrobutyricum. The process evaluated four nitrogen supplementation strategies (yeast extract, urea, ammonium sulfate, and no supplementation) to assess their impact on volatile fatty acids (VFAs) production. Among the conditions tested, the absence of nitrogen led to the fastest BA production, reaching a stationary phase within four days. However, sugar accumulation patterns suggested that nitrogen availability influences both substrate utilization and fermentation dynamics. Soybean hulls might be used as potential cell support, enhancing microbial growth and VFA yield. In contrast, gas production remained consistent across all nitrogen sources. These findings underscore the importance of optimizing nitrogen supply to improve VFA production in SSF processes using lignocellulosic biomass.