초록
<P><B>Abstract</B></P><P><B>Aims: </B> To improve the yield and productivity of docosahexaenoic acid (DHA) by <I>Schizochytrium</I> sp. in terms of the analysis of microbial physiology.</P><P><B>Methods and Results: </B> A two‐stage oxygen supply control strategy, aimed at achieving high concentration and high productivity of DHA, was proposed. At the first 40 h, K<SUB>L</SUB>a was controlled at 150·1 h<SUP>−1</SUP> to obtain high μ for cell growth, subsequently K<SUB>L</SUB>a was controlled at 88·5 h<SUP>−1</SUP> to maintain high <I>q</I><SUB>p</SUB> for high DHA accumulation. Finally, the maximum lipid, DHA content and DHA productivity reached 46·6, 17·7 g l<SUP>−1</SUP> and 111 mg l<SUP>−1</SUP> h<SUP>−1</SUP>, which were 43·83%, 63·88% and 32·14% over the best results controlled by constant K<SUB>L</SUB>a.</P><P><B>Conclusions: </B> This paper described a two‐stage oxygen supply control strategy based on the kinetic analysis for efficient DHA fermentation by <I>Schizochytrium</I> sp.</P><P><B>Significance and Impact of the study: </B> This study showed the advantage of two‐stage control strategy in terms of microbial physiology. As K<SUB>L</SUB>a is a scaling‐up parameter, the idea developed in this paper could be scaled‐up to industrial process and applied to other industrial biotechnological processes to achieve both high product concentration and high productivity.</P>