通气量和CO2对Nannochloropsis sp.在光生物反应器中的生长和EPA合成的影响

实验考察了在气升式内环流光生物反应器中通气量、CO2含量等培养条件对Nannochloropsis sp.生长及EPA合成的影响. 结果表明，在气升式内环流光生物反应器中培养，Nannochloropsis sp.生长速率显著提高. 培养8 d，Nannochloropsis sp.生物量(干重)可达857 mg/L，是摇床培养的2倍. 在一定范围内，Nannochloropsis sp.的生长速率随通气量的增加而增加，在本实验条件下，通气量为500 mL/min时生长最快，而过高的通气量则对Nannochloropsis sp.的生长没有促进作用. 在通气中含1%(j) CO2时，可加快藻细胞的生长，最大生长速率可达不配加CO2时的1.8倍. 通气量和CO2对Nannochloropsis sp.细胞内总脂肪酸及EPA的积累有显著影响. 在通气量为400 mL/min及CO2含量为0.5%时，培养液中EPA产量最高，达到39.0 mg/L.

Effects of Air Flow Rate and CO2 Concentration on the Growth of Nannochloropsis sp. and EPA Accumulation in an Airlift Photobioreactor

The effects of air flow rate and concentration of CO2 on the growth of Nannochloropsis sp. cells as well as EPA content in an airlift photobioreactor were investigated. The results show that Nannochloropsis sp. grew faster in the airlift photobioreactor than in the flask. After 8 d culture, the biomass of Nannochloropsis sp. in the airlift photobioreactor reached 857 mg/L, which was 2-fold of that obtained in the flask. The growth rate increased with the increase of air flow rate. Nannochloropsis sp. grew the fastest at the air flow rate of 500 mL/min and no positive effect on the cell growth was observed above this flow rate. 1% (j) CO2 added in the air promoted the growth of Nannochloropsis sp. significantly, thereby the maximal growth rate was 1.8-fold of that without CO2 addition. The highest EPA yield of the culture, 39.0 mg /L, was obtained at the air flow rate of 400 mL/min with 0.5% (j) CO2.