L-肉碱强化对异养小球藻种群增长、脂肪酸组成及相关酶活性的影响

Effects of L-carnitine Strengthening on Population Growth,Fatty Acid Composition and Related Enzyme Activities of Chlorella vulgaris

以不同质量浓度L-肉碱[0(ck),50,100,200 mg/L]在不同时间(6,24,96 h)强化异养小球藻(Chlorella vulgaris)144 h,研究L-肉碱对异养小球藻种群增长、脂肪酸组成及相关脂肪酸代谢酶活性的影响。结果表明:添加L-肉碱强化对异养小球藻种群增长有显著影响(P<0.05),各处理组种群密度均显著高于对照组(P<0.05)。在24 h时添加100 mg/L肉碱强化处理组种群密度最大,为3.083×10^(7)/mL,是起始浓度的6.17倍,同时样品收获量显著高于其他各处理组(P<0.05)。在小球藻异养培养24 h时添加100 mg/L肉碱能够通过提高乙酰辅酶A羧化酶、丙二酰基-CoA:ACP转酰基酶、β-酮脂酰-ACP合酶、Δ12脂肪酸去饱和酶活性,来改善其脂肪酸组成,尤其是多不饱和脂肪酸与n-3/n-6脂肪酸比值升高,进而促进其种群增长和改善其生化组成。

The experiments were conducted to enhance the effects of L-carnitine on population growth,composition of fatty acids and metabolic enzymes of the related fatty acids with different concentrations of L-carnitine[0(ck),50,100,200 mg/L] at different time(6 h,24 h,96 h).The results showed that:L-carnitine enrichment had a significant effect on population growth of heterotrophic chlorella(P<0.05),and population density of each treatment group was significantly higher than that of the control group(P<0.05).Population density of 100 mg/L L-carnitine treatment group reached the maximum at 24 h,which was 3.083×10^(7)/mL,6.17 times of the initial concentration,and harvest of samples was significantly higher than that of other treatment groups(P<0.05).Under the experimental conditions,adding 100 mg/L carnitine when heterotrophic chlorella was cultured for 24 h could improve composition of fatty acids by increasing activities of acetyl-coa carboxylase,propylene acyl-CoA:ACP acyl enzyme,beta-ketone fatty acyl-ACP synthase and Δ12 fatty acid desaturase.Ration of polyunsaturated fatty acid to n-3/n-6 fatty acid was especially increased,thus promoting population growth and improving its biochemical composition.