无机碳源对小球藻自养产油脂的影响

旨在研究小球藻利用无机碳自养产油脂，考察了3种无机碳源 (Na2CO3、NaHCO3和CO2) 及其初始浓度对小球藻产油特性的影响。结果表明，小球藻能利用Na2CO3、NaHCO3和CO2产油；经Na2CO3、NaHCO3和CO2培养10 d后，随着每种无机碳源浓度的增加，小球藻产量均先增加后减少。小球藻经3种无机碳源培养后，其培养液pH值上升。最适宜的Na2CO3和NaHCO3添加量均为40 mmol/L，其生物量分别达到0.52 g/L和0.67 g/L，产油量分别达到0.19 g/L和0.22 g/L。在3种无机碳源中，CO2是最佳无机碳源，当CO2浓度为6％时，小球藻生长最快，生物量达2.42 g/L，产油量最高达0.72 g/L；当CO2浓度过低时，无机碳供应不足，油脂产量低；当CO2浓度过高时，培养液pH偏低，小球藻油脂积累受到抑制。Na2CO3和NaHCO3较CO2更有利于小球藻积累不饱和脂肪酸。

Effect of inorganic carbon source on lipid production with autotrophic Chlorella vulgaris

We studied the effects of three inorganic carbon sources, Na2CO3, NaHCO3 and CO2, and their initial concentrations on lipid production of Chlorella vulgaris. Chlorella vulgaris could utilize Na2CO3, NaHCO3 and CO2 to produce lipids. After 10-day cultivation with each of the three inorganic carbon sources, lipid yield of Chlorella vulgaris reached its peak with the concentration increase of the inorganic carbon source, but dropped again by further increase of the concentration. The pH value of the culture medium for Chlorella vulgaris increased after the cultivation on inorganic carbon source. The optimal concentration of both Na2CO3 and NaHCO3 was 40 mmol/L, and their corresponding biomass dry weight was 0.52 g/L and 0.67 g/L with their corresponding lipid yield 0.19 g/L and 0.22 g/L. When the concentration of CO2 was 6%, Chlorella vulgaris grew the fastest and its biomass dry weight was 2.42 g/L with the highest lipid yield of 0.72 g/L. When the concentration of CO2 was too low, the supply of inorganic carbon was insufficient and lipid yield was low. A too high concentration of CO2 caused a low pH and lipid accumulation was inhibited. Na2CO3 and NaHCO3 were more favorable for Chlorella vulgaris to accumulate unsaturated fatty acids than that of CO2.