共培养小球藻和胶球藻对生物量和油脂产率的影响

Coculture effects of Auxenochlorella protothecoides and Coccomyxa subellipsoidea on biomass and lipid accumulation

该文通过优化接种比例、接种时序和碳氮比构建了小球藻和胶球藻最佳共培养体系,并探究了小球藻和胶球藻最佳共培养对生物量和油脂产率的影响.结果显示,小球藻和胶球藻种子液接种体积比为3∶7,生长起始同步接入碳氮比为32的培养基构建的培养体系为最佳,此培养条件下小球藻和胶球藻获得的生物量和油脂产率最大值分别为1.13 g/(L·d)和1.22 g/(L·d),是单一小球藻和胶球藻培养获得生物量和油脂产率的1.75~2.46倍和3.21~4.52倍,且生长周期较单一微藻培养均缩短72 h.共培养小球藻和胶球藻胞内淀粉和蛋白质含量较单一培养藻株显著性下调1.19~1.47倍和1.59~1.71倍,推测其可能是由于小球藻和胶球藻共培养效应驱动更多的碳流由淀粉和蛋白质合成方向转而流向脂质路径.进一步流加补料发酵,共培养小球藻和胶球藻获得的生物量和油脂产率较分批共培养小球藻和胶球藻分别提高2.54倍和1.61倍.研究结果证实了小球藻和胶球藻共培养可有效促进生物量和脂质积累,为微藻脂质工业化扩大生产奠定了基础.

Coculture system of Auxenochlorella protothecoides(A.protothecoides)and Coccomyxa subellipsoidea(C.subellipsoidea)was established by optimizing inoculation ratio,inoculation time sequence and carbon to nitrogen ratio.The influences of coculture of A.protothecoides and C.subellipsoidea on biomass and lipid productivity were also investigated in this work.The results demonstrated that the optimal coculture system of A.protothecoides and C.subellipsoidea was A.protothecoides to C.subellipsoidea inoculation volume ratio 3∶7,synchronized inoculation sequence of A.protothecoides and C.subellipsoidea,carbon to nitrogen ratio 32.The achieved maximum biomass and lipid productivity of coculture of A.protothecoides and C.subellipsoidea were separately 1.13 g/(L·d)and 1.22 g/(L·d)under the optimal coculture condition,which were 1.75-fold to 2.46-fold and 3.21-fold to 4.52-fold more than sole A.protothecoides and C.subellipsoidea.And the growth cycle of coculture of A.protothecoides and C.subellipsoidea was shortened 72 h than the growth of sole A.protothecoides and C.subellipsoidea.However,starch and protein contents of coculture A.protothecoides and C.subellipsoidea showed 1.19-fold to 1.47-fold and 1.59-fold to 1.71-fold down-regulation than sole microalgal species,which might be due to that A.protothecoides and C.subellipsoidea coculture effects drove more carbon flow from starch and protein pathway into lipid pathway consequently promoted lipid accumulation.Fed-batch fermentation co-culture of A.protothecoides and C.subellipsoidea showed that the biomass and lipid productivity were further increased to 2.54-fold and 1.61-fold than sole A.protothecoides and C.subellipsoidea.The findings confirmed that microalgae co-culture could effectively promote biomass and lipid accumulation and laid a foundation for the industrial expansion of lipid production in microalgae.