| dc.description.abstract |
Currently, the most important bio-butanol production technology is ”ABE fermentation” system, and the main fermentation products were acetone, butanol, and ethanol. However, ABE fermentation was facing two problems: first, high energy demanding separation and concentration downstream process; second, the poor tolerance of the bacteria to butanol. Therefore, this study used a new type of temperature-responsive sponge that can change its hydrophilic/ hydrophobic properties at different temperatures, as an adsorbent to extract butanol, trying to solve the problem of high energy demanding and butanol inhibition of bacteria.
In this study, the temperature-responsive sponge (PNIPAAm-PDMS) was prepared by polydimethylsiloxane (PDMS) as substrate and modified by poly(N-isopropylacrylamide) (PNIPAAm) at the surface. FTIR and TGA analysis were proved that PNIPAAm was successfully grafted onto PDMS. Due to PNIPAAm had a lower critical solution temperature, we designed the procedure to adsorb butanol at the fermentation temperature (37℃) and sponge at the room temperature (25℃). In the butanol solution, the results of sponge adsorption/desorbtion show that the PNIPAAm-PDMS sponge can increase the adsorption/desorption capacity of butanol. Therefore, we applied this procedure to continuous extraction with semi-continuous fermentation systems, sponge extraction and feed were carried out at the 48th hour and 60th hour, respectively. Compared with the productivity and yield of the control group, 0.85 g/l day and 0.181 g butanol/g glucose, the PNIPAAm-PDMS sponge continuous extraction with the semi-continuous fermentation system got the best productivity (2.00 g/l day) and yield (0.191 g butanol/g glucose).
In this study, we used a new energy-saving temperature-responsive hydrophobic sponge, designed high temperature (37℃) adsorption and low temperature (25℃) desorption, which could save the energy of ABE fermentation product separation program. It will effectively reduce the inhibitory effect and increase the butanol yield, through the sponge continuous extraction to remove the butanol in the fermentation broth. Therefore, it is worthy to study the feasibility of the fermentation process of PNIPAAm-PDMS composite sponge as extractant. | en_US |