营养方式对小球藻生长性能及营养价值的影响

Effect of different trophic modes on the growth performance and nutrition of Chlorella sp.

分别对小球藻Chlorellasp.2003ZGH023进行光合自养、混合营养高碳、混合营养低碳和异养低碳培养,探讨不同营养方式对小球藻生长及细胞营养组成的影响。结果表明,在基础培养基中添加有机碳源,可显著提高小球藻的细胞密度和生物量,其中异养低碳组细胞密度可达54.73×106cell/ml,生物量6.86 g(dw)/L,且混合营养和异养小球藻细胞体积变大。在细胞营养组成上,与自养小球藻细胞相比,异养培养的小球藻细胞内蛋白含量显著下降而脂肪含量显著增加。光合自养组、混合营养高碳组、混合营养低碳组和异养组小球藻细胞粗蛋白含量分别是41.88%±0.14%、24.60%±0.07%、21.93%±0.13%和12.91%±0.35%。不同营养方式下小球藻的氨基酸总量变化与其粗蛋白含量的变化趋势相一致,光合自养组>混合营养高碳组>混合营养低碳组>异养组。小球藻总脂肪含量最高的为混合营养高碳组(15.32%±1.58%)和异养低碳组(14.15%±0.93%),显著高于混合营养低碳组(12.35%±0.25%)和光合自养组(10.04%±0.39%)。小球藻的脂肪酸组成会随着营养方式的改变而改变,光合自养组小球藻的主要脂肪酸为18∶3n3和14∶1,混合营养组小球藻的主要脂肪酸为14∶1和18∶1n9,异养低碳组中小球藻的主要脂肪酸为18∶1n9和16∶0。

A Chlorella strain 2003ZGH023 was cultured at modes of photoautotrophic（light,basic nutrient formula）,mixotrophic with high carbon level（light,basic nutrient formula,8 gram organic carbon per liter）,mixotrophic with low carbon level（4 gram organic carbon perliter）,and heterotrophic with low carbon level（darkness,basic nutrient formula,4 gram organic carbon per liter） respectively.The effects of different trophic modes on the growth performance and nutritional composition of the Chlorella were studied.The results indicated that the addition of organic carbon in culture medium significantly increased the cell density and biomass of the Chlorella.The heterotrophic group had a cell density as high as 54.73×106 cell/ml,and biomass of 6.86 g（dw）/L.The sizes of the Chlorella cells in heterotrophic and mixotrophic groups were larger than that in autotrophic group.The assays on nutrition showed that the protein content of the Chlorella cell declined significantly while the total fat content increased significantly in the heterotrophic modes.The crude protein contents in the photoautotrophic mode,mixotrophic mode with high carbon level,mixotrophic mode with low carbon level and heterotrophic mode were 41.88%±0.14%,24.60%±0.07%,21.93%±0.13% and 12.91%±0.35% respectively.The variation of amino acid content in cell at different trophic modes was consistent with that of crude protein.The total lipids in the mixotrophic mode with high-carbon group（15.32%±1.58%） and the heterotrophic mode with low-carbon group（14.15% ± 0.93%） were significantly higher than those in the mixotrophic mode with low-carbon group（12.35% ± 0.25%） and the photoautotrophic mode（10.04% ± 0.3%）.There were significant differences in fatty acid compositions of cell cultured in different trophic modes.Fatty acids 18∶3n3 and 14∶1 were dominant in photoautotrophic Chlorella.Fatty acids 14∶1 and 18∶1n9 were the majority in the mixotrophic modes.Fatty acids 18：1n9 and 16：0 were the most abundant in the heterotrophic mode.