Study on Using Algal Biomass for Bioethanol Production

• Main Authors: Yi-Chun Liao, 廖易濬
• Other Authors: Ing-Lung Shih
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/29695760926291301591

碩士 === 大葉大學 === 環境工程學系碩士班 === 102 === In recent years, the use of fossil fuels causes environmental pollution and the greenhouse effect. The concern of fast depletion of fossil fuels and global warming has led people to actively look for alternative sources of energy. Taiwan is surrounded by sea and have rich marine resources. it is well suited to develop and cultivate algae as a bio-feedstock. Algae have high fiber and rapid growth characteristic, they are loosely structured than terrestrial plants and more susceptible to hydrolysis therefore, they are very suitable materials for biomass energy production in Taiwan. This study is to investigate the use of red algae as a feedstock for the production of bio-ethanol. This study have three parts: The first part includes analysis the composition of algae (Gracilaria cliftonii and Chlorella sp. Y8-1) and study of their saccharification. The main components of Gracilaria cliftonii and Chlorella sp. Y8-1 are crude fiber, they are 76.67% and 65.47% , respectvely. The Optimal saccharification process found was when alage powders were hydrolyzed by 0.1 H2SO4 at 131℃, for 60 min, which was followed by adjusting pH to 4.5, addition of 1% cellulase and incubation at 50℃for 6h Under such conditions, the main sugars released in the hydrolysate of Gracilaria and Chlorell were glucose 6.3 g/L(31.5%), 5.19 g/L(25.8%) and galactose 5.6 g/L(27.8%), 1.65 g/L(8.1%), respectvely. The second part is to screen a strain that are capable of co-fermentation of glucose and galactose for bioethanol production. It was found that a newly isolated yeast strain Saccharomyces cerevisiae Wu-Y2 showed a good performance on co-fermentation of glucose and galactose. In the hydrolysate of Gracilaria cliftonii.The final ethanol concentration of 4.72 g/L (94% conversion efficiency) were achieved, overall 1g of dry Gracilaria can be produced to 0.23g of ethanol. The third part is to investigate the fermentation of Gracilaria hydrolysate by immobilized Saccharomyces cerevisiae Wu-Y2 in a bioreactor. The result showed that when 300 mL of Gracilaria hydrolyzate was supplying with 2 g/L yeast extract and fermented by addition of 10% of immobilized cells by continuous feeding of hydrolyzate at 2.3mL/ min for 96h, the average ethanol concentration was 4.1 g/L. Overall 13.2 g/L of hydrolysate was added, and 5.4g of ethanol was obtained.