兼养对雨生红球藻细胞生长的促进作用及藻株差异性

摘要

The general and different characteristics of cell growth, photosynthetic performance index (PIABS) of 4 strains of Haematococcus pluvialis under mixotrophic (light+sodium acetate) conditions were studied by using chlorophyll a fluorescence and the cell growth rate. The results show that mixotrophic cultivation could significantly improve specific growth rate and cell densities in H. pluvialis compared with phototrophic cultivation. Sodium acetate (NaAc) not only provided organic carbon substance to Haematococcus for heterotrophic growth but also changed its PIABS of phototrophic growth. Interestingly, PIABS in mixotrophic culture was obviously lower than that of autotrophic culture on the first day, but became significant higher than that of autotrophic culture during the later culture period. The cell growth in mixotro-phic cultivation could be further divided into heterotrophic growth and autotrophic growth, and the above analysis indi-cates that the fast growth of cells at the early culture stage of mixotrophic cultivation mainly came from its heterotrophic growth, and that at the late culture stage was mainly contributed by its autotrophic growth. Moreover, the adaptabilities to sodium acetate and the optimum concentrations for growth of H. pluvialis varied greatly within different strains. Strain H0 required a relative high NaAc concentrations and exhibited the fastest cell growth among the 4 tested strains, while strain H6 presented a low NaAc demands and exhibited the slowest cell growth. Above results indicate that mixotrophic culture seems to be an effective way to shorten the production cycle and to improve biomass of H. pluvialis in mass cul-ture with suitable NaAc concentration addition for each strain.%结合叶绿素荧光技术，对比研究了不同雨生红球藻藻株在兼养(光照+乙酸钠)培养过程中细胞生长和光合作用的共性与差异性反应。结果表明：兼养明显提高红球藻细胞密度和比生长速率；乙酸钠不仅为红球藻提供异养的有机碳源，而且还明显导致藻细胞光自养的光合综合性能指数发生改变，兼养对细胞生长促进作用的贡献在前期主要来自于其中的异养部分，而在后期却明显来自于自养部分；兼养对细胞生长的促进作用在藻株之间存在一定差异，不同藻株对乙酸钠的适应能力和最适质量浓度也存在明显差异，藻株H0可适应的乙酸钠质量浓度较高，而藻株H6对乙酸钠需求和适应性相对较低。上述结果意味着规模化培养红球藻过程中，针对不同藻株采用适宜乙酸钠兼养方式可有效缩短培养周期，提高生产效率。