以濃醪發酵技術利用高梁生產酒精之研究

Very high gravity(VHG) fermentation from sorghum mash to produce ethanol

黃禮彥(Li-Yen Huang)

指導教授 ： 段國仁

大同大學/工程學院/生物工程學系所/碩士(2008年)

摘要

高梁生長在台灣西部靠海的平原，以及金門與連江縣地區等含鹽強風的地方，種植高梁能避免土壤被海風侵蝕，不會與其它的糧食作物爭地。高梁穀粒中主要成分為澱粉(60~70%)，且生長期約為4個月，為一種有潛力的燃料酒精作物。
本實驗以高梁穀粒為原料，進行酒精發酵的研究。研究使用一株商用活性乾酵母 (Ethanol RedTM)，在探討培養基的最適化發現0.5% (w/v) 酵母抽出物，16 mM尿素，能提高酵母對於酒精的耐受能力，有利於非常高濃度的高梁酒醪的發酵。
本研究先以22實驗法探討2公升的高梁酒醪 (40 %, w/v)補充含有游離胺基酸之氮源(酵母抽取物，尿素)對於酒精發酵的影響。在同步糖化發酵的程序中，補充游離胺基酸使酒精生產速率高達3.03 g-ethanol/L-h，酒精濃度為145 g/L，發酵時間48小時。相對於沒有補充游離胺基酸的結果是酒精生產速率0.93 g-ethanol/L-h，酒精濃度為144.4 g/L，發酵時間156小時。若是採用先糖化後發酵的程序，有補充游離胺基酸的結果是酒精生產速率2.18 g-ethanol/L-h，酒精濃度為140 g/L，發酵時間64小時。相對於沒有補充游離胺基酸的結果是酒精生產速率0.68 g-ethanol/L-h，酒精濃度為125.1 g/L，發酵時間185小時。
利用擠壓之高梁澱粉，以同步糖解發酵並添加尿素與YE，其平均酒精產率為3.63 g L-1 h-1，發酵時間40小時、酒精濃度145.2 g/L，擠壓之澱粉，可縮短酵母生長至穩定生長期所需之時間。

關鍵字

生質酒精 ； 酒精發酵 ； 高梁

並列摘要

Sorghum, cultivated in the arid area along the west coastal line of Taiwan, Chinmen and Lienchiang counties, is used to prevent from land erosion due to strong wind. Sorghum is not competing for arable land, can be harvested within 4 months, contained 60~70 % (w/w) starch, making it an ideal raw materials for ethanol production.
This study employed sorghum grain as raw material for ethanol production using an commercial active dry yeast. The medium optimization was found that 0.5% (w/v) yeast extract and 16 mM urea greatly improved the ethanol tolerance for the yeast propagation, making it possible for very high gravity (VHG) ethanol fermentation.
A 22-like design of experiment was implemented to investigate the effect of free amino nitrogen (FAN) on the sorghum fermentation at a very-high-gravity (VHG) condition. The overall ethanol production rate was 3.03 g ethanol/L-h (equivalent to 145.4 g ethanol/L in 48 h when FAN was supplemented) compared to 0.93 g ethanol/L-h (equivalent to 144.4 g ethanol/L in 156 h when FAN was not added) by using simultaneous saccharification and fermentation. Whereas, the overall ethanol production rate was 2.18 g ethanol/L-h (equivalent to 139.9 g ethanol/L in 64 h when FAN was provided) compared to 0.68 g ethanol/L-h (equivalent to 125.1 g ethanol/L in 185 h when FAN was not added) by using the operation of saccharification followed by fermentation.
The extruded sorghum was employed as another kind of raw material in ethanol production. The overall ethanol production rate was 3.63 g ethanol/L-h (equivalent to 145.2 g ethanol/L in 40 h when FAN was supplemented by using simultaneous saccharification and fermentation. The extruded sorghum could reduce the lag phase of yeast propagation in the fermentation process.

並列關鍵字

bioethanol ； ethanol fermentation ； sorghum

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