培养条件对湛江等鞭金藻生长和油脂产率的影响

Effects of cultivation conditions on cell growth and lipid productivity of microalgae Isochrysis zhanjiangensis

为提高微藻油脂产率和优化培养条件,以湛江等鞭金藻(Isochrysis zhanjiangensis)为研究对象,探讨了营养方式、光强和NaNO_3浓度对微藻生长和产物积累的影响以及培养过程中氮消耗与微藻生长间的关系。结果表明,湛江等鞭金藻生长越快,对氮的吸收越多,兼养较光自养和光异养消耗更多的氮以满足生长需要。充足的氮源和兼养培养条件下,蛋白质积累较多;氮浓度和光强较低条件下,油脂积累较多。光强为100μmol/(m2·s)、NaNO_3质量浓度为75 mg/L、光异养条件下油脂含量最高为46%,生物量质量浓度为0. 46 g/L;光强为100μmol/(m2·s)、NaNO_3质量浓度为750 mg/L、兼养培养时生物量质量浓度最高为2. 20 g/L,油脂含量为32. 77%。综合考虑油脂产率和节约成本等因素,湛江等鞭金藻最高油脂产率80. 06 mg/(L·d),在光强为100μmol/(m2·s)、NaNO_3质量浓度为375 mg/L、兼养培养条件下获得,此时多不饱和脂肪酸占总脂肪酸含量也较高(30. 82%),因此是生产微藻油脂的合适条件。

In order to improve the microalgae lipid productivity and optimize its cultivation conditions,Isochrysis zhanjiangensis was used as the research object,effects of trophic modes,light intensity,and NaNO3 concentration on the growth and lipid accumulation,as well as the relationship between nitrogen consumption and growth in the course of culture were explored.The results showed that microalgae consumed more nitrogen while it grew faster.Compared to photoautotrophic and photoheterotrophic cultivation,more nitrogen was consumed to meet the growth needs under mixotrophic cultivation condition.More protein were accumulated under the conditions of sufficient nitrogen and mixotrophic cultivation,whereas more oil accumulated under the conditions of low nitrogen concentration and light intensity.Although the highest oil content of 46% was obtained under the photoheterotrophic cultivation when the light intensity was 100μmol/(m^2·s) and NaNO3 concentration was 75mg/L,the biomass concentration was only 0.46g/L under the same condition.The highest biomass concentration of 2.20g/L was obtained under the mixotrophic cultivation when the light intensity was 100μmol/(m^2·s) and NaNO3 concentration was 750mg/L.However,the oil content was only 32.77%.Considering factors,such as lipid productivity and cost-saving,the best lipid productivity of 80.06 mg/(L·d) was obtained under the mixotrophic cultivation when the light intensity was 100μmol/(m^2·s) and NaNO3 concentration was 375mg/L.Moreover,polyunsaturated fatty acids accounted for 30.82% of the total fatty acids contents under this condition.Therefore,this is a suitable condition for I.zhanjiangensis to produce microalgae oil as a nutritional substitute.