隨著原油價格快速上升以及可預測的未?石油供應?減少，過?使用石化燃?所造成的環境衝擊使得可再生性的替代燃?逐漸引起人們的重視。其中生物柴油因具有與現有動?設備相容的使用特性，因此其商業生產備受各方的矚目，因此美國能源部將生物柴油的生產歸?為目前?即可使用的技術之一，生物柴油具有相對石化柴油的優越表現包括較高的生物?解，較低毒性和?低的汙染物排放。儘管如此，生物柴油的商業化?產仍舊擁有需多的困難，其最大的限制點在於較高的製造成本。由於生物柴油的製造成本有70-90％是?自於其所使用植物油的原?成本。過?依賴植物油的使用?生產生物柴油，將會造成可耕種面積做為人??食比?大?的?低，進一步造成?食的價格上揚，因此尋找可替代性的油脂?源是近幾??研究的重點。其中含高油脂的油脂微生物 (Oleaginous microorganisms)也是研究的重點之一，當油脂含?超?微生物重?20-25％即被歸?高油脂含?的微生物，目前已知有許多的微生物具有相當高含?的微生物油脂(single cell oils)，其中又以藻?培養取得油脂之研發最受重視。藻?雖然可?用光合作用進?繁殖，大?的?低培養基成本。但藻?的培養過程中，包括光源的提供，藻?細胞的收集以及甚至到後段的細胞破碎與油脂萃取目前還是有一些瓶頸的存在。相對於藻?培養而言，酵母菌擁有生長速?較快，且菌體濃?較高等特性，對於後續分?純化相較藻?較為簡?等特性，因此本構想書擬採用酵母菌 (Rhodotorula glutinis)的培養?取得油脂，並進一步探討轉換成生物柴油的可?性。主要探討的主題將包括三大部分; (一) ?用回應曲面法進?培養基與控制條件最適化，培養基碳源的選擇將以甘油作為優先考慮 (二)將最適化條件放大至桌上型發酵槽，並以添加純氧進?溶氧控制與饋?批次(fed-batch)的方式以達到高密?培養R. glutinis 的目的。本計畫預計建?桌上型發酵槽進?酵母菌R. glutinis 生產油脂之最適發酵程序，最終目標為高密?培養酵母菌R. glutinis 於桌上型發酵槽內達到菌體濃? 80 g/l 以上，且總油脂含?達60% (grams of lipid/grams of biomass)以上，並希望在相對合?的?據支持下，優先考慮以甘油作碳源以增加未?商業化大?生產的可?性。 With the soar-up price, the rapid consumption of the petroleum oil and the increasing concerns of environmental impacts resulting from over consumption of fossil fuels had drawn more and more research attention in the seeking of alternative renewable energy. To be a viable substitute for a fossil fuel, an alternative fuel should not only have superior environmental benefits over the replaced fossil fuel (such as the less pollutants emission), but also be economically competitive with the current fossil oils. One of the most prominent renewable energy resources is biodiesel, which is produced from renewable biomass by transesterification. It theoretically contributes no net carbon dioxide or sulfur to the atmosphere and emits less gaseous pollutants than normal fossil diesel. In the production of worldwide biodiesel, various renewable lipids have been chosen, including vegetable oils, animal fats, and kitchen waste oils. As compared to conventional petroleum diesel, at present the high price of biodiesel is a major obstacle to its commercialization. The reasons leading to high production cost of biodiesel is mainly from the high cost of raw materials, making it a less competitive fuel. Therefore, a cheap raw material is crucial for the commercialized production of biodiesel. The biological production of single cell oils (SCO) from oleaginous microorganisms was one of the choices for being the renewable oil source converted to biodiesel. Oleaginous microorganisms are defined as microbial with the content of microbial lipid excess of 20% (g/g). Biodiesel production using microbial lipids, which is named as single cell oils (SCO), has attracted great attention in the recent years. Numerous oleaginous yeasts and microalgaes have been reported to grow and accumulate significant amounts of lipids similar to vegetable oil. The oil production by yeast-Rhodotorula glutinis was proposed in this study. Three major topics would be investigated in this study including; 1) the screening of high oils production strain by UV (or NTG) mutation and a oil staining agent- Nile red, 2) The fermentation process optimized by response surface methodology (RSM) to find the optimal parameters and 3) the feeding criteria and the DO control criteria for achieving high cell density cultivation. The target of this study was to establish a microorganism oil production process of R. glutinis with high cell density over 80 g/l and the oil content over 60%.
