Establishment of lignocellulose digestion system with functional rumen bacterial consortia for biofuel production
| Autor: | Jia-Jen Lin, 林嘉仁 |
|---|---|
| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 Biofuel production is integrated biomass conversion processes to produce fuels, power, and value-added chemicals from biomass in a biorefinery concept, for example, bio-hydrogen, ethanol, and butanol could generate electricity and process heat. It is a renewable energy source based on the carbon cycle. Lignocellulose is the most abundant renewable feedstock to produce biofuel. Lignocellulose is composed of cellulose, hemicelluloses, lignin. Cellulose is surrounded by hemicellulose, lignin, and pectin. This study was aimed to establish a functional rumen bacterial consortia as a lignocellulose digestion system for biofuel production through serial repeated batch culture. The major bacterial composition of batch culture was monitored and the result showed that a stable consortia constituted by ruminal microflora designated FRBC was formed, included Clostridium xylanolyticum 98%、Clostridium puniceum 98%、Clostridium papyrosolvens 98%、Ruminococcus sp. 98%、Clostridium beijerinckii 98%. On an eight day incubation period, the functional consortia could produce 86.9 mL H2 and ethanol 1250 mg/L, and degrade an average of 26% hemicellulose and 6% cellulose from napiergrass biomass. Time course profile for extracellular enzymes showed that the hydrolysis of complex lignocellulosic material may occur through the ordered actions of xylanase and cellulase activities. Two strains, Ru6 and Ru15 were isolated from FRBC and phylogenetic analysis based on 16S rDNA and indicated that the bacteria were closely related to Clostridium puniceum and Clostridium xylanolyticum, respectively. Clostridium puniceum Ru6 has xylanase, pectinase activity and hydrogen producing ability. The fermentation end products from PYG are ethanol, butanol, acetic, and butyric acid. The optimum condition for growth is 37℃ and pH 6.0~8.0. Ru6 could produce 87.8 mL H2, ethanol 72 mg/L, butanol 1.4 mg/L under lignocellulosic substrate concentrations of 50 g/L. Clostridium xylanolyticum Ru15 has endoglucanase, xylanase, pectinase activity and hydrogen producing ability. The fermentation end products from PYG are ethanol, butanol, and acetic acid. The optimum condition for growth is 30~37℃ and pH 8.0. Ru15 could produce 65.7 mL H2, ethanol 1626 mg/L under lignocellulosic substrate concentrations of 50 g/L. The co-culture condition of Ru6 and Ru15 is further studied to carry out the consolidated bioprocessing CBP for biofuel production. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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