光径及氮浓度对缺刻缘绿藻生长、油脂和花生四烯酸积累的影响
EFFECTS OF LIGHT-PATHs AND NITROGEN CONCENTRATION ON THE GROWTH, TOTAL LIPIDS AND ARACHIDONIC ACID ACCUMULATION OF PARIETOCHLORIS INCISA
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摘要: 以缺刻缘绿藻(Parietochloris incisa)为实验材料, 采用BG-11培养基, 分别在2种氮浓度和3种不同光径(LP)的柱状和平板光生物反应器中进行培养, 并探究其生长、油脂和花生四烯酸(AA)的积累规律。结果显示: 在两种光生物反应器中, 光径越小, 越有利于缺刻缘绿藻的生长。其中, 最大生物量均在17.6 mmol/L氮浓度时获得, 分别为5.09 g/L(2.5 cm-柱状)和2.98 g/L(3.0 cm-平板); 而最高油脂和AA绝对含量则均在1.0 mmol/L氮浓度和最大光径处获得, 分别为39.23%、13.21%(6.0 cm-柱状)和40.74%、11.33%(5.0 cm-平板); 另外, 两种光生物反应器中的最大油脂单位体积产率分别可以达到216.39 mg/(L·d)(17.6 mmol/L; 2.5 cm-柱状)和135.93 mg/(L·d)(1.0 mmol/L; 1.5 cm-平板); 而最高的AA单位体积产率均在1.0 mmol/L低氮条件, 最大光径处达到最大, 分别为21.65 mg/(L·d)(6.0 cm-柱状)和19.42 mg/(L·d)(5.0 cm-平板)。因此, 根据实际生产需要, 在1.0 mmol/L低氮条件下, 选择6.0 cm光径的柱状光生物反应器或5.0 cm光径的平板光生物反应器, 培养缺刻缘绿藻生产AA, 能有效降低生产成本。Abstract: This study explored effects of 3 light-paths (LP) of column and flat plat photobioreactors under two kinds of nitrogen concentrations on the growth, total lipid and AA content of Parietochloris incisa using BG-11 medium. The results showed that cell growth rate increased by the smaller light-path of two kinds of photobioreactors. The maximal biomass were 5.09 g/L in column photobioreactor (2.5 cm LP) and 2.98 g/L (3.0 cm LP) in flat plate photobioreactor with nitrogen concentration at 17.6 mmol/L. The highest total lipid and AA content at the biggest length of light-path under 1.0 mmol/L nitrogen concentration were 39.23% and 13.21% in column photobioreactor (6.0 cm LP) and there were 40.74% and 11.33% in flat plate photobioreactor (5.0 cm LP). In addition, the maximal volumetric productivity of total lipid was 216.39 mg/(L·d) in column photobioreactor (2.5 cm LP) under 17.6 mmol/L nitrogen concentration and it was 135.93 mg/(L·d) in flat plate photobioreactor (1.5 cm LP) under 1.0 mmol/L nitrogen concentration. The AA volumetric productivity reached the maximum level in the biggest light-path of column 21.65 mg/(L·d) and flat plate photobiorector 19.42 mg/(L·d) under 1.0 mmol/L nitrogen concentration. These results indicate that the 6.0 cm light-path column photobioreactor or 5.0 cm light-path of flat plate photobioreactor under 1.0 mmol/L nitrogen concentration are the best condition to culture Parietochloris incisa for AA production.