碩士 / 國立臺灣海洋大學 / 食品科學系 / 103 / The objective of this study is to develop fermentation techniques for producing bio-butanol from green algae Monostroma nitidum and to conduct life cycle assessment (LCA) analysis for the potential bio-butanol production protocol. The main works including hydrolyzing M. nitidum or its hot water polysaccharides (PS) extracte with hot acid, commercial cellulases, and crude enzymes from strain P. vesicularis MA103 (MA103) and A. salmonicida MAEF108 (MAEF108). The hydrolysates of M. nitidum were used to produced bio-butanol through anaerobic batch and fed-batch fermentation to obtain further yield of biofuel. And the evaluations on production cost and carbon footprint of various product protocol are also conducted. The reducing sugar content of desalted or fresh 5% (w/v) M. nitidum after hot acid hydrolyzing were 0.25 and 1.50 g and these salt concentration were 1.46 and 1.75 mg/mL, respectively. After 3 times added (2%, 2%, 1%) and added in once of 5 g M. nitidum into 100 mL water for hot acid hydrolysis, the total sugars and reducing sugars are 1.92 and 1.93 g and 1.33 and 1.28 g, respectively. The later showed similar hydrolysis efficiency and lower cost than former. The 760 U or 4,560 U cellulases are reacted with 100 mL effect of M. nitidum (5%, w/v) solution at pH 4.5 and 26oC for 24 hr, the results showed total sugars and reducing sugars were 2.39 and 2.97 g and 1.88 and 2.04 g, respectively. The 4,560 U cellulase hydrolysis group is higher than 760 U group, but 760 U cellulase treatment was used in the following experiment based on the lower cost. Multiple crude enzymes from strains MA103 and MAEF108 were induced by 3 kinds M. nitidum: powder, fresh, and desalting. The results showed that strains MAEF108 and MA103 had better agarase and xylanase enzyme activities (1.11 U and 0.07 U) at the third day when the desalting M. nitidum used as an inducing substrate. Adaptation experiment on butanol producing strain Clostridium acetobutylicum BCRC10639 and C. beijerinckii BCRC17950 with 4.5% salt concentration broth, developed two salt tolerant strains which are named C. acetobutylicum BCRC10639-ST (salt tolerant) and, C. beijerinckii BCRC17950-ST. Gas-stripping systems (I) ethanol (-20 oC) and (II) dry ice + ethanol (-80oC) were tested for their recovery rate with 0.5%, 1.5%, and 35% butanol solution, results indicated that the recovery rates for system (I) were 9.4%, 9.7%, and 35%, as well as for system (II) were 18%, 16%, and 72%, respectively. The loss rates of these tested gas-stripping systems for system (I) were 33%, 32%, and 64%, and for system (II) were 25%, 27%, 4%, respectively. Hydrolysate of Mn (Monostroma nitidum)-CL (low cellulase activity)-Si (salt intolerant strain)-B (Batch) and Mn-DS (Desalted)-CL-Si-B (100 mL) fermented by strains BCRC10639/BCRC17950 could produce 3.49% and 4.00% bio-butanol after anaerobically fermented at 37oC for 5 days. Butanol yields of procedures Mn-CH (high cellulase activity)-Si-B and Mn-DS-CH-Si-B were 3.92% and 4.49% after anaerobically fermented at 37oC for 5 days in 100 mL solution. Both of their butanol yields were higher than the M. nitidum that hydrolysed by 760 U cellulase, and the desalted M. nitidum showed better butanol yield than fresh M. nitidum. Procedure Mn-DS-CL-St (salt tolerant strain)-B and Mn-DS-CH-St-B (100 mL) used desalted M. nitidum as substrate and hydrolyzed by 760 U or 4,560 U cellulase, respectively, and then fermented by BCRC10639-ST/17950-ST, showed the highest butanol yield of 6.71% (day 5) and 6.31% (day 2), respectively. Procedure Mn-DS-CL-Si-B and Mn-DS-CL-St-B (100 mL) fermented by salt intolerant or salt tolerant strains for 5 days, both showed the highest butanol yields of 3.49% and 6.71% in day 3, respectively. Gas striping technique (-20oC Ethanol) were applied in procedure Mn-DS-CL-St-B to increase the fermentation yield of bio-butanol, when desalted M. nitidum used as substrate of batch fermentation, the butanol yield is 7.02% in day 2. In the fed-betch fermentation procedures Mn-Ds-CL-St-FB-GSE (-20oC) and Mn-Ds-CL-St-FB-GSDE (-80oC), the highest butanol yield achieved in day 2, which were 6.66% and 6.98%, and the butanol concentrations of fermentation solution were 0.42% and 0.44%, respectively. The later (-80oC, GSDE) showed higher butanol concentration in day 5, and its butanol production amount increased from 6.6 g in day 2 to 8.8 g. Based on the lost rate of gas stripping 25%, while -80oC (dry ice + ethanol) recovery condition and 0.5% (v/v) butanol was used as fermentation solution. The postulated butanol concentration and yield of butanol of protocol Mn-Ds-CL-St-FB-GSDE will be by 25%, 0.68% and 3.60%, which are higher than the collected data. Therefore, if the lost rate of gas stripping could lower down, the yield of collected butanol from various production protocol could be improved. After analyzed by LCA, the cost of butanol producting per L by protocols of Mn-Ds-CL-St-FB-GSE and Mn-Ds-CL-St-FB-GSDE were 24,791 and 23,279 NTD, which were 93.08% and 78.77% than production protocol Mn-Ds-CL-St-B-GSE had. As to the amount of carbon footprints, they both higher than the later, increased for 86.21% (63,802.29 kg) and 75.26% (60,066.27 kg), respectively. If self-made cellulase as well as MA103/MAEF108 and clostridia culturing broth used were replaced for commercial cellulase and media in the production, the cost of procedure Mn-Ds-CL-St-FB-GSDE cost could dropped to 50890.59 NTD, 350.39 NTD and 534,243.04 NTD. The cost to producing 1 L butanol could dropped to 22,710 NTD. In the future, if the addition of 10% bio-butanol into gasoline is applied, the amount of environmental benefits could reach 2,960,706,619 NTD.
| Identifer | oai:union.ndltd.org:TW/103NTOU5253077 |
| Date | January 2015 |
| Creators | Yi, Tsung-Kai, 易琮凱 |
| Contributors | Pan, Chorng-Liang, 潘崇良 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 128 |
Page generated in 0.0155 seconds