A stable culture environment is the key for optimal growth and metabolic activity of microorganisms, especially in marine species, and intermittent feeding during DHA production using Schizochytrium sp. generates an unstable culture environment. To investigate the effect of unstable culture environment on the cells’ physiological status and DHA synthesis, fermentations with different feeding strategies were performed on the lab scale. The intermittent feeding strategy caused fluctuations of substrate concentration and osmotic pressure, which had a negative effect on cell division and product synthesis. The physiological status and metabolic level of Schizochytrium sp. were relatively stable under a continuous feeding strategy with a relatively stable substrate concentration of 20–25 g/L, which was beneficial for the efficient transformation of substrate, leading to an improvement of DHA productivity. This strategy was further applied to pilot scale, whereby the DHA content, DHA productivity, convert ratio of glucose to lipid and DHA reached 55.02%, 320.17 mg/(L·h), 24.35%, and 13.40%, respectively. This study therefore provides an efficient strategy for ensuring a stable culture environment for the production of DHA and similar metabolites.

Graphical Abstract

稳定的培养环境对于微生物（尤其是海洋物种）的最佳生长和代谢活性以及在使用Schizochytrium sp的DHA生产过程中的间歇饲喂至关重要。产生不稳定的文化环境。为了研究不稳定培养环境对细胞生理状态和DHA合成的影响，在实验室规模下进行了不同喂养策略的发酵。间歇喂养策略导致底物浓度和渗透压的波动，这对细胞分裂和产物合成具有负面影响。裂殖壶菌的生理状态和代谢水平sp。在连续进料策略下相对稳定，底物浓度相对稳定，为20–25 g / L，这有利于底物的有效转化，从而提高了DHA的生产率。将该策略进一步应用于中试规模，由此DHA含量，DHA生产率，葡萄糖与脂质的转化率和DHA分别达到55.02％，320.17 mg /（L·h），24.35％和13.40％。因此，这项研究为确保产生DHA和类似代谢产物的稳定培养环境提供了有效策略。

图形概要