Fuqiang Jin

Microbial and nutritional regulation of high-solids anaerobic mono-digestion of fruit and vegetable wastes

ABSTRACT The anaerobic digestion of single fruit and vegetable wastes (FVW) can be easily interrupted by rapid acidogenesis and inhibition of methanogen, and the digestion system tends to be particularly unstable at high solid content. In this study, the anaerobic digestion of FVW in batch experiments under mesophilic condition at a high solid concentration of 10% was successfully conducted to overcome the acidogenesis problem through several modifications. Firstly, compared with the conventional anaerobic sludge (CAS), the acclimated anaerobic granular sludge (AGS) was found to be a better inoculum due to its higher Archaea abundance. Secondly, waste activated sludge (WAS) was chosen to co-digest with FVW, because WAS had abundant proteins that could generate intermediate ammonium. The ammonium could neutralize the accumulated volatile fatty acids (VFAs) and prevent the pH value of the digestion system from rapidly decreasing. Co-digestion of FVW and WAS with TS ratio of 60:40 gave the highest biogas yield of 562 mL/g-VS and the highest methane yield of 362 mL/g-VS. Key parameters in the digestion process, including VFAs concentration, pH, enzyme activity, and microbial activity, were also examined.

Butanol production of Clostridium pasteurianum SE-5 from transesterification reaction solution using fermentation and extraction coupling system

This study investigates the capability of the Clostridium pasteurianum SE-5 to produce butanol using transesterification reaction solution (TRS) directly, while the crude glyecerol as the sole carbon source and biodiesel as the extractant. The biodiesel: aqueous phase volume ratio (BAPVR) has a significant effect on butanol production. While the BAPVR was adjusted to 1:1, 89.1 g crude glycerol/L was exhausted and 24.6 g butanol/L was produced with more than 50% of the butanol was extracted into the biodiesel. The results suggested that C.pasteurianum SE-5 could produce butanol from TRS directly using fermentation and extraction coupling system.

Study on the in-situ coupling process of fermentation, extraction and distillation for biobutanol production: process analysis

The transfer process of the in-situ coupling process of fermentation, extraction and distillation for biobutanol production was discussed from a theoretical point of view. The existence of temperature gradient in the extraction section was proved. The force of solute in the extracted liquid was discussed. And the mass transfer mechanism and impetus of the FEDIC process was analyzed. The theoretical analysis could provide a foundation for the following research.