不同营养盐及浓度对黄丝藻Tribonema sp. FACHB-1786生长及脂质积累的影响

Effects of different nutrients and their concentrations on growth and lipid accumulation of Tribonema sp. FACHB-1786

摘要:

丝状微藻黄丝藻Tribonema sp.具有抗浮游动物捕食、易收获、油脂含量高等优点，且其脂肪酸组分中含有丰富的棕榈油酸 (Palmitoleic acid，PA) 和二十碳五烯酸 (Eicosapentaenoic acid，EPA)，被认为是生产生物柴油和高附加值产品的重要原料。为了提高黄丝藻脂质生产效率，文中研究了不同浓度的氮 (NaNO3：255–3 060 mg/L)、磷 (K2HPO4：4–240 mg/L)、铁 ((NH4)3FeC12H10O14：0.6–12 mg/L)、镁 (MgSO4：7.5–450 mg/L) 元素对黄丝藻FACHB-1786生长、油脂积累和脂肪酸组分的影响。结果表明，培养基中磷、铁、镁三种元素的浓度对黄丝藻生长具有显著影响，其中增加MgSO4浓度可显著提高黄丝藻的生物量，当MgSO4浓度增加至450 mg/L时，获得最大生物量为8.09 g/L，显著高于目前报道的有关黄丝藻自养条件下获得的生物量；氮元素浓度对黄丝藻的生长没有显著影响 (P>0.05)，但高浓度氮元素有利于黄丝藻脂质的积累；黄丝藻FACHB-1786在765 mg/L NaNO3、80 mg/L K2HPO4、6 mg/L (NH4)3FeC12H10O14、75 mg/L MgSO4的营养盐条件下可获得最大总脂单位体积产率、棕榈油酸和EPA产率，分别为319.6 mg/(L·d)、135.7 mg/(L·d)和24.2 mg/(L·d)。研究结果为后期黄丝藻的生产应用提供一定的理论依据和参考。

Abstract:

Filamentous microalga Tribonema sp. has the advantages of highly resistance to zooplankton-predation, easy harvesting, and high cellular lipid content, in particular large amounts of palmitoleic acid (PA) and eicosapentaenoic acid (EPA). Therefore, Tribonema sp. is considered as a promising biomass feedstock to produce biodiesel and high-value products. In this work, we studied the effect of different concentrations of nitrogen (NaNO3: 255–3 060 mg/L), phosphorus (K2HPO4: 4–240 mg/L), iron ((NH4)3FeC12H10O14: 0.6–12 mg/L) and magnesium (MgSO4: 7.5–450 mg/L) on the biomass, lipid content, and fatty acid composition of Tribonema sp. FACHB-1786, aiming at enhancing cell lipid productivity. The growth of Tribonema sp. had a positive correlation with the concentration of magnesium, and the maximum biomass of Tribonema sp. (under the condition of 450 mg/L MgSO4) was 8.09 g/L, much greater than those reported in previous studies using the same and other Tribonema species under autotrophic conditions. Different nitrogen concentrations exerted no significant effect on algal growth (P > 0.05), but a higher nitrogen concentration resulted in a greater amount of lipid in the cells. The maximum volumetric productivities of total lipids (319. 6 mg/(L·d)), palmitoleic acid (135.7 mg/(L·d)), and eicosapentaenoic acid (24.2 mg/(L·d)) of Tribonema sp. were obtained when the concentrations of NaNO3, K2HPO4, (NH4)3FeC12H10O14, and MgSO4 were 765 mg/L, 80 mg/L, 6 mg/L, and 75 mg/L, respectively. This study will provide a reference for substrate optimization for Tribonema sp. growth and lipid production.