碩士 / 國立雲林科技大學 / 環境與安全衛生工程系 / 103 / The awakening to the fossil fuel limitation and sustainable development forces human to explore renewable and environmental friendly energy. Bioethanol is one potential candidate because it can be produced using pretreated lignocellulosic biomass, the most abundantly available raw material on the EarthIn recent years, algal biomass is considered as the idealraw material to produce renewable energy because of itshigh cellulosecontent and fast growth rate. Moreover, algae are well-known carbon dioxide capturer. Algae can be incubated in freshwater or seawater so thatthe land demand is minor. Taiwan is a small island country but surrounded by abundant algal resources. Using algal biomass for renewable energy production in Taiwan may be an ideal way to approach sustainable future. Thermal acid hydrolysis is extensively used to pretreat algal biomass because of economic and efficient consideration. However, the main drawback of thermal acid hydrolysis is to produce inhibitor compounds such as acetic acid, furfural and 5-hydroxymethyl furfural (5-HMF) during hydrolysis. These inhibitor compounds will influence downstream bioethanol fermentation. For better bioethanol yield, inhibitor compounds removal is an important issue.
In 2004, US Department of Energy suggests top 14 biomass platform molecules for the sustainable future.. Among these compounds, 2,5-furan-dicarboxylic acid (FDCA) can be produced by 5-HMFbio-transformation. Basing on the connection between 5-HMF removal in the algal acid hydrolysate and FDCA production, microbes capable of biotransforming 5-HMF into FDCA could be beneficial to high bioethanol yield and potential molecule production.
In this study, we collected algaChaetomorpha linumfrom waste fishing field as the raw material for thermal acid hydrolysis.To find out the best hydrolysis condition to obtain high reducing sugar concentration and hydrolysis efficiency, various parameters (acid sorts, algal concentrations, acid concentrationsand hydrolysis time) were investigated. In addition, potential microbes transforming 5-HMF into FDCA were enriched and isolated from an activated sludge tank of food factory and campus soil.Their abilities of 5-HMF biotransformation and FDCA production were investigated under various initial pHs, temperatures and 5-HMF concentrations. The isolates were also used to biotransform 5-HMF into FDCA in the algal acid hydrolysate.
Optimum thermal acid hydrolysis condition was to apply0.5 M HCl to treat 3% algae at 121℃ for 15 minutes. The highest reducing sugar concentration and hydrolysis efficiencywere 6.32 g/L and 50%, respectively. There were 14 strains isolated from the activated sludge of soy sauce wastewater treatment system and the campussoil. Among these isolates, strain G-2 and H-2, the most potential two strains, were identified as Methylobacterium radiotolerans and Burkholderia cepacia, respectively, by 16S rDNA sequences.Strain MethylobacteriumradiotoleransG-2 could completely transform 1000 mg/L 5-HMF into FDCA at initial pH of 7 at 26C and maximum FDCA concentration was 513.9 mg/L. Strain Burkholderia cepacia H-2 transformed 2000 mg/L 5-HMF into FDCA at initial pH of 7 at 28C and 1276 mg/L FDCA was received.For 5-HMF biotransformation in the algal acid hydrolysate, 2-fold dilution was suitable for strain MethylobacteriumradiotoleransG-2, and 459.7 mg/L FDCA was obtained. Reducing sugar consumption was less than 16%. Strain Burkholderia cepacia H-2 was suitable to treat the algal hydrolysate without dilution, and 989.5 mg/L FDCA was received, but reducing sugar consumption was high, 43%.
| Identifer | oai:union.ndltd.org:TW/103YUNT0633022 |
| Date | January 2015 |
| Creators | CI- RUEI HUANG, 黃啟睿 |
| Contributors | CHU-FANG YANG, 楊茱芳 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 115 |
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