混合营养模式下3种有机物对蛋白核小球藻生长及细胞组成的影响

以一株新分离的蛋白核小球藻SHOU-1002(Chlorella pyrenoidosa SHOU-1002)为试验材料,设置分别添加葡萄糖、谷氨酸钠和酵母浸出物的3组混合营养组和光合自养组,比较不同营养模式下蛋白核小球藻的生长及细胞组成的差异。结果表明：在混合营养模式下接种后蛋白核小球藻细胞密度始终显著高于光合自养组(P＜0.05)。接种后6d内葡萄糖组的藻细胞密度显著高于谷氨酸钠组和酵母浸出物组(P＜0.05)；第10d起,3个混合营养组藻细胞密度无显著性差异(P＞0.05)。培养第12d,谷氨酸钠组和酵母浸出物组的叶绿素a、类胡萝卜素、蛋白和总脂含量显著高于葡萄糖组(P＜0.05),碳水化合物含量则显著低于葡萄糖组(P＜0.05)。随培养时间的延长,葡萄糖组的饱和脂肪酸(SFAs)含量不断升高,多不饱和脂肪酸(PUFAs)含量不断降低；谷氨酸钠组和酵母浸出物组的PUFAs含量则先降低后升高；培养第12d,谷氨酸钠组和酵母浸出物组的PUFAs含量显著高于葡萄糖组(P＜0.05)。表明该株蛋白核小球藻具有混合营养能力且混合营养模式下其生长效能显著提升,混合营养模式下添加酵母浸出物或谷氨酸钠所培养的藻细胞较添加葡萄糖所培养的藻细胞具有更高的营养价值。

Effects of three organic substances on the growth and cell composition of Chlorella pyrenoidosa under mixotrophic mode

The growth and cell composition of a newly isolated strain of Chlorella pyrenoidosa were compared in three mixotrophic groups (treated with glucose, sodium glutamate and yeast extract, respectively), and a photoautotrophic group. The results showed that, generally, the cell density of mixotrophic groups were significantly higher than the photoautotrophic group after inoculation (P<0.05). Moreover, the cell density of the glucose group was significantly higher than that of the sodium glutamate group and the yeast extract group within 6 days after inoculation (P<0.05). Additionally, there was no significant difference in the cell density of the three mixotrophic groups from the 10^th day (P>0.05). On the 12^th day, the contents of chlorophyll a, carotenoids, protein and total lipid in the sodium glutamate group and yeast extract group were significantly higher as compared to those in the glucose group (P<0.05); however, the carbohydrate content was significantly lower compared to the glucose group (P<0.05). Further, in the glucose group, SFAs increased while the PUFAs decreased with the prolongation of culture time. The PUFAs in the sodium glutamate group and the yeast extract group tended to decrease in the beginning then they increased. The PUFAs of the sodium glutamate group and the yeast extract group were significantly higher than that of the glucose group on the 12^th day (P<0.05). In conclusion, the results suggested that Chlorella pyrenoidosa has the ability to mixotrophy and its growth efficiency is significantly improved in mixotrophic mode. Besides, the algal cells cultured by yeast extract or sodium glutamate had better nutritional value than those cultured by glucose.