一株产油微藻的筛选及分子鉴定

A NEWLY SELECTED LIPID-RICH MICROALGAE STRAIN AND ITS MOLECULAR IDENTIFICATION

  • 摘要: 利用通气培养系统, 对10株经过初步生长筛选的微藻进行培养, 以总脂单位体积产率为主要指标, 筛选具有产油潜力的优良藻种。结果表明, 10株微藻的生物质干重、总脂含量分别为0.81.6 g/L、14.8%39.7%, 总脂单位体积产率大于30 mg/(Ld)的有6株, 其中藻株HY-6总脂单位体积产率达到最高的50.8 mg/(Ld), 是一株具有潜力的产油微藻。运用形态学特征和18S rDNA及ITS系统学分析相结合的方法对藻种HY-6进行分类鉴定。依据形态学特征, HY-6为球状单细胞, 具有1个明显的蛋白核, 杯状色素体周生, 从而初步判断该藻株可能属于小球藻属(Chlorella)或拟小球藻属(Parachlorella); 18S rDNA及ITS系统学分析表明HY-6与小球藻属分为两个不同的进化支, 但与凯氏拟小球藻(Parachlorella kessleri)的亲缘关系较近, 且具有较高的自展支持率, 因此将其鉴定为凯氏拟小球藻(P. kessleri)。研究结果将为产油微藻资源的收集、筛选及后续研究提供基础。

     

    Abstract: Ten pre-selected microalgae were cultivated in a bubble column photobioreactor, and tested for their lipid production potential using lipid productivity as a key characteristic. The results showed that their biomass dry weights and total lipid contents ranged from 0.8 g/L to 1.6 g/L and 14.8% to 39.7%, respectively. Six strains of all investigated species had lipid productivity greater than 30 mg/(Ld). The strain HY-6, which had the highest lipid productivity 50.8 mg/(Ld), can be a candidate species for biodiesel production. Taxonomic evaluation of the strain HY-6 was performed on the basis of morphological observation and phylogenetic analyses of concatenated 18S ribosomal RNA gene and internal transcribed sequence. HY-6 was preliminarily identified to belong to either the genus Chlorella or Parachlorella on the basis of its morphological characteristics such as spherical single cell, one well-defined pyrenoid and cup-shaped chloroplast. Phylogenetic analyses of 18S rDNA and ITS of coccoid green algae within the Chlorella and the Parachlorella clades of Chlorellaceae further identified HY-6 as Parachlorella kessleri.

     

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