促进黄丝藻储能物质高效富集的氮调控策略

Nitrogen regulatory strategies for promoting efficient enrichment of energy storage compounds in Tribonema sp.

为了促进黄丝藻胞内储能物质的高效积累,研究了不同氮形态(NO_(3)^(-)、Urea和NH_(4)^(+))及初始氮浓度(1、3、6、9、18 mmol/L)对黄丝藻生长、碳水化合物和总脂积累的影响,在此基础上建立了基于氮调控促进黄丝藻生物量和储能物质同步高效积累的“低氮(初始氮浓度3 mmol/L)转高氮(初始氮浓度18 mmol/L)”两步法培养策略,并对两步法培养策略的培养时间进行优化。结果表明:与Urea和NH_(4)^(+)比较,黄丝藻更倾向于利用NO_(3)^(-),分别在3 mmol/L和18 mmol/L条件下获得最高生物量(3.69 g/L)和总脂含量(57.3%);在“低氮转高氮”两步法培养中,低氮培养时间6 d转高氮培养12 d可显著提高黄丝藻胞内储能物质的积累,储能物质产率最高,达到274.26 mg/(L·d),其中生物量、总脂产率和碳水化合物产率分别为6.37 g/L、152.92 mg/(L·d)和121.35 mg/(L·d)。基于“低氮转高氮”的氮调控两步法是一种极具前景的培养模式,可在保证总脂产率相当的情况下显著提高生物量和碳水化合物产率。

In order to promote efficient enrichment of energy storage compounds in Tribonema sp.,the effects of different nitrogen forms(NO_(3)^(-),Urea and NH_(4)^(+))and initial nitrogen concentration(1,3,6,9,18 mmol/L)on the growth,carbohydrate and lipid accumulation of Tribonema sp.were investigated.Then a two-step culture strategy from low nitrogen(initial nitrogen concentration 3 mmol/L)to high nitrogen(initial nitrogen concentration 18 mmol/L)based on nitrogen regulation was established to promote the simultaneous and efficient accumulation of biomass and energy storage compounds in the alga,and the culture time of the two-step culture strategy was optimized.The results indicated that the highest biomass concentration(3.69 g/L)and total lipid content(57.3%)were obtained at 3 mmol/L and 18 mmol/L of NO_(3)^(-) in Tribonema sp.,respectively,compared with Urea and NH_(4)^(+).In the two-step culture strategy of"low nitrogen to high nitrogen",6 d of low nitrogen culture to 12 d of high nitrogen culture could significantly increase the accumulation of energy storage compounds in Tribonema sp.,and the highest energy storage compounds yield was 274.26 mg/(L·d),of which the biomass and yields of total lipid and carbohydrate were 6.37 g/L,152.92 mg/(L·d),121.35 mg/(L·d),respectively.The two-step nitrogen regulation based on"low nitrogen to high nitrogen"is a promising culture model that can significantly increase biomass and carbohydrate yield while ensuring comparable total lipid yield.