| Abstract: | 地球能源隨著國際經濟的熱絡而有耗竭的現象，因此尋找替代能源成為迫切且緊要的事情。生質能源當中微藻是非常好的生產者，其光合效率特別高，生物質量與生長速率均優於其它能源作物 (Dote et al., 1994；Minowa et al., 1995)。在微藻種類裡，小球藻(Chlorella sp.)擁有高蛋白質含量以及高脂質累積量的潛能(Becker, 1994)並且取得容易，所以本研究以此為探討對象。
為了要讓細胞生物質量生產出高的柴油量，必須要先得到細胞內高的脂質含量與油脂量(Mutsumi et al., 2006)，本研究先以 Chlorella sp.於不同濃度CO2的自營性培養做探討，再以不同C/N比濃度的異營性培養為基礎，了解自營與異營培養之間的差異，接著透過異營與類自營二階段式的培養提高Chlorella sp.細胞胞內脂質含量和總油脂量。
實驗結果顯示，自營培養環境下，20% CO2的培養有最高的總油脂量與胞內脂含量，分別為0.45 gL-1與70%，生長速率為0.0242 day-1(培養1-12天之間)。而在異營培養實驗，C/N比為7或14對最大油脂量與胞內脂質含量影響不明顯，甚至對生物質量也是如此，分別為0.4 gL-1、20%和1.5 gL-1，生長速率為2.1 day-1(培養24-44小時間)。在異營結合類自營性二階段培養實驗結果，顯示此模式最大總油脂量增為初始值的3.25倍，明顯優於異營性培養(C/N比為7)之最大增加量為初始值的2倍，自營性培養則為原始的1.5倍。
The global fossil fuel consumption is demanding and supposed to be used up by A.D. 2050(Ginzburg, 1993) while economy and population are continuously growing. Substitution of the energy resources have been researched for decades including the wind-powered energy, solar energy and the production of biodiesel mainly by agricultural activities. The microalgae have been suggested as one of a good resource of bio-fuel production due to its higher photosynthesis efficiency, higher biomass production and higher growth rate comparing to other energy crops such as the sugar cane, beet and corn…etc. (Dote et al.,1994; Minowa et al., 1995).The objective of the research is to increase the lipid content of Chlorella sp., a kind of microalgae, by two-step (heterotrophic and stressed pseudo-autotrophic) cultivation strategy.
The results of the autotrophic cultivation by applying two different concentrations of CO2 (0, 3%, 20%) come out that the maximum lipid production and lipid content in 20% CO2 culture, 0.45 gL-1 and 70% respectively.
The result of the heterotrophic cultivation by applying two different carbon-to-nitrogen ratios (C/N = 7, 14) of nutrients come out that both the C/N = 7 and C/N = 14 have the maximum lipid production, lipid content and biomass production, which are 0.4 gL-1,20% and 1.5 gL-1 respectively.
The results of the two-step cultivation by combining the nutrients of carbon-to-nitrogen ratios (C/N = 7) with CO2 (20%) come out that the lipid production and lipid content have the maximum ratio, which are 3.25 and 1.6 respectively. The lipid production and lipid content of the two-step cultivation are better then heterotrophic or autotrophic cultivation alone evidently. |
