以二階段培養模式培養小球藻(Chlorella sp.)生產油脂之研究

Abstract

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.