产油微藻的分离鉴定及营养方式对其油脂积累的影响

为了获得高产油微藻,以从海南水体样本中分离得到微藻C67为出发株,考察其在不同营养方式下生长及油脂积累情况。形态观察及Lsu（large subunit）基因分析鉴定其为微芒藻C67（Micractinium reisseri C67）;微芒藻C67主要脂肪酸为C18：1、C16：0、C18：3和C18：2,分别占总脂肪酸的33%、26%、18%和11%;微芒藻C67在混合营养方式下藻体质量浓度及油脂质量分数明显高于自养与异养方式,在以葡萄糖为碳源的混合营养方式下微芒藻藻体质量浓度最高（7.0 g·L-1）,以甘氨酸（Gly）为碳源的混合营养方式下微芒藻C67油脂质量分数最高（40.2%）,以葡萄糖为碳源的混合营养方式下微芒藻C67总脂质量浓度为2.2 g·L-1,分别是自养和异养方式的7.3倍和7.9倍。

Isolation and identification of lipid-producing microalgae and effect of different trophic modes on its oil accumulation

The freshwater microalga,strain C67,was isolated from a freshwater lake in Hainan and selected as a high lipid producer.The biomass productivity and lipid content of the microalgal strain were analyzed under different trophic cultivation modes including au-tophototrophic,mixotrophic and heterotrophic cultivations.The strain was tentatively identified as Micractinium reisseri C67 based on microscopic examination and Lsu（large subunit） rDNA sequence analysis.Major fatty acids in the microalgae were C 18：1,C 16：0,C 18：3 and C18：2,comprising 33%,26%,18% and 11% of the total fatty acids,respectively.The biomass productivity and lipid content of M.reisseri C67 under mixotrophic cultivation were higher than those of under autotrophic and heterotrophic cultivations.The maximum biomass productivity（7.0 g·L-1） and the maximum lipid content（40.2%） of M.reisseri C67 were achieved under mixotrophic cultivation with glucose and glycine（Gly）,respectively.The lipid productivity of M.reisseri C67 was 2.2 g·L-1,7.3 and 7.9 folds of those obtained under autophototrophic and heterotrophic conditions,respectively.