光照强度对四株海洋绿藻总脂含量和脂肪酸组成的影响

Effect of light intensity on the total lipid contents and fatty acid composition in 4 strains of marine green algae

采用f/2培养基,在3000lx,5000lx,8000lx光照强度时对杆状裂丝藻(Stichococcus bacillaris,MACC(中国海洋大学微藻种质库)/C19)和3株小球藻(Chlorellasp.MACC/C95,MACC/C97和MACC/C102)等4株海洋绿藻的总脂含量及脂肪酸组成进行了研究。单因子方差分析结果表明,光照强度对4株海洋绿藻的相对生长率、EPA(二十碳五烯酸,20∶5(n-3))含量及PUFA(多不饱和脂肪酸)总量,C19、C97和C102的脂肪含量和SFA(饱和脂肪酸)总量,C19、C95和C102的MUFA(单不饱和脂肪酸)总量均有显著影响(P<0.05)。C19和C95的总脂含量随光照强度的增加总体呈降低趋势,C97和C102的总脂含量则随光照强度的升高而明显升高。C19的EPA含量随光照强度的增加呈现低-高-低趋势,C95在中低光照强度下EPA含量较高,C97和C102的EPA含量则随光照强度的增加而明显降低,4株绿藻的AA(花生四烯酸,20∶4(n-6))含量和PUFA总量均随光照强度的增加而降低。多重比较结果表明:C19在高光照强度(8000lx)时总脂含量显著低于其它各组,低光照强度(3000lx)和中光照强度(5000lx)处理间没有显著性差异(12.9%—12.7%),C97和C102则分别在高光照强度时总脂含量显著高于其它各处理(分别为40.6%和33.3%)。C19的EPA含量在中光照强度水平显著高于其它处理(12.7%),C97和C102的EPA含量分别在低光照强度水平显著高于其它处理(分别为12.0%和10.5%),C95的EPA含量在高光照强度水平显著低于其它处理,低光照强度和中光照强度处理间没有显著性差异(14.0%—14.7%);C19和C95的PUFA总量均在高光照强度水平显著低于其它处理,在低光照强度和中光照强度处理间没有显著性差异(分别为19.1%—19.4%和21.3%—21.3%),C97和C102的PUFA总量均在低光照强度水平显著高于其它处理(分别为19.2%和18.9%)。4株绿藻的主要脂肪酸成份为14∶0、16∶0、16∶1(n-7)、16∶4(n-3)、18∶1(n-9)、18∶3(n-3)、20∶4(n-6)和EPA。

The total lipid contents and fatty acid composition in four strains of marine green algae（Stichococcus bacillaris MACC/C19,Chlorella sp.MACC/C95,MACC/C97 and MACC/C102） cultivated under different light intensities（3000lx,5000lx and 8000lx） in f/2 medium were determined.One-way analysis of variance showed that light intensity had significant effects on the relative growth rates,eicosapentaenoic acid（EPA,20∶5（n-3）） and subtotals of polyunsaturated fatty acids（PUFA） contents of 4 strains of green algae（P〈0.05）.Light intensity had significant effects on the total lipid contents and subtotals of saturated fatty acids（SFA） of C19,C97 and C102（P〈0.05）.Light intensity also had significant effect on subtotals of monounsaturated fatty acids（MUFA） of C19,C95 and C102（P〈0.05）.The total lipid contents weakly decreased with the increase of light intensity in C19 and C95,however it was significantly increased with the increase of light intensity in C97 and C102.The proportions of EPA decreased with the increase of light intensity in all strains except C19,the proportions of 20∶4（n-6） and subtotals of PUFA in all 4 strains decreased with increasing light intensity.Multiple comparison tests showed that the total lipid content in C19 grown at high light intensity（8000 lx） was lower than those grown at other treatments,but was not significantly different between the treatments of low light intensity（3000 lx） and middle light intensity（5000 lx）（12.9% and 12.7% of the dry weight,respectively）.C97 and C102 had the highest total lipid contents（40.6% and 33.3% of the dry weight,respectively） when grown at high light intensity.The proportion of EPA in C19 reached its highest value（12.7% of total fatty acids） when grown at middle light intensity,and the proportions in C97 and C102 of EPA reached their highest values（12.0% and 10.5% of total fatty acids,respectively） when grown at low light intensity.The proportion of EPA in C95 grown at high light intensity was lower than those grown at other treatments.However there was no significant difference between the treatments of low light intensity and middle light intensity（14.0% and 14.7% of total fatty acids,respectively）.The subtotals of PUFA in C19 and C95 cultivated at high light intensity were lower than those cultivated at other treatments.However there was no significant difference between the treatments of low light intensity and middle light intensity（19.1%-19.4% and 21.3%-21.3% of total fatty acids,respectively）.The subtotals of PUFA in C97 and C102 reached their highest values（19.2% and 18.9% of total fatty acids,respectively） when light intensity was 3000 lx.The main fatty acids of 4 strains of marine green algae were 14∶0,16∶0,16∶1（n-7）,16∶4（n-3）,18∶1（n-9）,18∶3（n-3）,20∶4（n-6） and EPA.