Comparison of photoautotrophic and mixotrophic cultivation of microalgae Messastrum gracile (Chlorophyceae) in alternative culture media

Abstract Growth and biological conditions of Messastrum gracile were evaluated to compare the effect of photoautotrophic and mixotrophic cultivation on the increase of biomass production and chemical conditions cultured in macrophyte and commercial culture media. The growth rate (k) of M. gracile was different in the culture media, higher in mixotrophic cultivation for Lemna minor culture medium, whilst to Eichhornia crassipes and NPK culture media were higher in photoautotrophic cultivation. Mean lipid contents in photoautotrophic cultivation were 8.2% biomass dry weight, whereas they reached 19% biomass dry weight in mixotrophic cultivation. Protein contents were below 48% biomass dry weight in photoautotrophic cultivation and 30% biomass dry weight in mixotrophic cultivation. Messastrum gracile cultured in macrophyte culture media (E. crassipes and L. minor) and NPK culture medium provided satisfactory results with regard to lipid and protein contents in mixotrophic and photoautotrophic cultivations, respectively. Lipid and protein contents in alternative media were higher or similar to the CHU12 commercial culture medium.

摘要：本研究评估了纤细Messastrum藻（Messastrum gracile）的生长及生物学特性，旨在比较光能自养培养（photoautotrophic cultivation）与混合营养培养（mixotrophic cultivation）对大型植物培养基（macrophyte culture media）及商业化培养基（commercial culture media）中生物量产率提升的影响，并分析其培养后的化学组分特征。该藻在不同培养基中的生长速率（growth rate, k）存在差异：以小浮萍（Lemna minor）培养基进行混合营养培养时生长速率更高，而以凤眼莲（Eichhornia crassipes）培养基与氮磷钾（NPK）培养基培养时，光能自养模式下的生长速率更优。光能自养培养下的平均脂质含量（lipid contents）为生物干重（biomass dry weight）的8.2%，而混合营养培养下该数值可达生物干重的19%。光能自养培养的蛋白质含量（protein contents）低于生物干重的48%，混合营养培养下则低于生物干重的30%。采用大型植物培养基（凤眼莲、小浮萍培养基）与氮磷钾（NPK）培养基培养的纤细Messastrum藻，在混合营养与光能自养模式下分别可获得令人满意的脂质与蛋白质组分表现。替代培养基中的脂质与蛋白质含量均高于或接近商业化CHU12培养基。