Heterotrophic-photoautotrophic two-stage culture is an effective method to improve the oil performance of microalgae. The Present study investigated the effects of fulvic acid on the growth and lipid accumulation of Monoraphidium sp. FXY-10 under two-stage cultivation. Four different fulvic acid concentrations of 40, 80, 120, and 160 mg/L were used to find the optimum concentration for FXY-10 growth under heterotrophic cultivation. Further-more, the method of combining fulvic acid and heterotrophic-photoautotrophic two-stage cultivation was used to en-hance the biomass and oil content of FXY-10. Four different concentrations of fulvic acid (5, 25, 125, and 625 mg/L) were employed to stimulate lipid accumulation at the photoautotrophic cultivation phase. The results showed that 80 mg/L fulvic acid (6.41 g/L)increased biomass to 1.5-fold compared with the control. However, 160 mg/L fulvic acid seriously inhibited cell growth. At the photoautotrophic stage, the lipid content increased from 30.78% to 54.65% by 25 mg/L fulvic acid. The results indicated that fulvic acid could significantly increase biomass and lipid content of mi-croalgae. The combination of fulvic acid and two-step cultivation can enhance the biomass and oil accumulation of mi-croalgae.%为了研究不同浓度的黄腐酸对单针藻Monoraphidium sp.FXY-10细胞生长、油脂合成的影响,研究于Kuh1培养基中添加4种不同浓度的黄腐酸(40、80、120和160 mg/L),优化出异养培养条件下最适合藻细胞生长的黄腐酸浓度;并采用黄腐酸与异养-自养两步培养联用的方法提高细胞量和油脂含量,自养培养时在培养基中添加5、25、125和625 mg/L的黄腐酸诱导油脂的合成.结果表明,80 mg/L的黄腐酸对细胞生长的促进作用最显著,细胞量可达6.4 g/L,为对照组的1.5倍.黄腐酸的浓度增加至160 mg/L,藻细胞的生长受到明显的抑制.自养培养阶段,添加25 mg/L的黄腐酸能显著地提高藻细胞的油脂含量,其油脂含量从30.78%增加至54.65%.黄腐酸对于单针藻的生长和油脂合成具有明显的促进作用,黄腐酸与两步法联用在提高微藻细胞量和油脂含量方面具有较好的应用前景.
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