| 摘要: | 目前最重要的生質丁醇生產技術為「ABE發酵」系統，其主要的發酵產物為丙酮(acetone)、丁醇(butanol)、以及乙醇(ethanol)，然而卻面臨到兩個難題，分別是提取及純化濃縮產物的程序造成能量損耗，以及菌株對丁醇耐受性不佳而有抑制作用產生的問題。因此本研究將使用一種新型節能溫度感應海綿作為一種吸附劑來提取丁醇，藉由在不同溫度下其親水/疏水性質改變，讓海綿具有可重複利用性，及節省產物分離程序的能量，並移除發酵產物丁醇以降低對菌株的抑制作用。
本實驗中使用聚二甲基矽氧烷Polydimethylsiloxane(PDMS)為主體，並在表面上修飾Poly(N-isopropylacrylamide) (PNIPAAm)的高分子複合海綿(PNIPAAm-PDMS)。在材料鑑定上用FTIR及TGA進行定性和定量分析，證明成功將PNIPAAm修飾到PDMS表面。由於PNIPAAm具有低臨界溶解溫度(lower critical solution temperature，LCST)，因此，我們設計在發酵溫度(37℃)下進行海綿的丁醇吸附，以及在室溫(25℃)下進行海綿的丁醇脫附之操作程序。在丁醇溶液中，海綿吸附/脫附丁醇的結果也顯示，複合海綿能增加對丁醇的吸附/脫附能力。因此我們將此操作程序應用在連續萃取結合半連續式發酵系統中，在發酵的第48小時開始進行海綿萃取，並且在發酵的第60小時進行饋料。發酵結果與控制組的生產率(0.85 g/l day)及產率(0.181 g butanol/g glucose)相比，複合海綿連續萃取結合半連續式發酵系統，能得到最佳的生產率(2.00 g/l day)及產率(0.191 g butanol/g glucose)。
本研究中，我們使用一種新型節能溫度感應的疏水海綿，設計出高溫(37℃)吸附、低溫(25℃)脫附的節能回收製程，將有效降低丁醇回收所消耗的能量，以及透過海綿連續萃取移除發酵液中的丁醇，將有效減少抑制作用、提升丁醇產量。因此PNIPAAm-PDMS複合海綿作為萃取劑之發酵製程可行性，值得深入探討。
;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. |
