Controlling concentrations of glucose and dissolved oxygen (DO) at high and sufficient level could be considered as an important factor for effective production of docosahexaenoic acid (DHA) by Schizochytrium sp.S31. However, the structure and skeleton of cells would be obviously damaged with severe accumulations of reactive oxygen species (ROS) when cells were subjected to the environment of sufficient DO for a long time, which eventually lead to a limited DHA production. To solve these questions, a combinational control strategy of “glucose sufficient-periodic dissolved oxygen concentration operation” was proposed. When using this strategy, glucose concentration was maintained at about 40 g/L throughout the entire cultivation (feeding) phase. At the same time, in the DO control scheme, typical cultivation (feeding) phase was divided into ten 10 h subintervals, during which alternate DO supplement was applied, namely sufficient DO for the first 8 h and limited DO for the last 2 h. When using this combinational strategy, the maximum concentration of intracellular ROS could be decreased from 209.37 fluorescence intensity(FI)/g DCW to 146.38 FI/g DCW; the distribution of glucose to cell maintenance was decreased from 0.026 6 1/h to 0.021 2 1/h; the activities of key enzymes involved in DHA biosynthesis metabolism, cell growth rate and glucose consumption rate were apparently improved; DHA concentration reached the highest level of 13.69 g/L, which was increased by 40.3% and 256.1%, respectively, compared to that of the traditional control strategies of “glucose sufficient-DO limited” (3.92 g/L) and “glucose sufficient-DO sufficient” (9.76 g/L).
REN Jun
,
WU Zhaomei
,
CHEN Zhiyan
. Enhancing DHA production by Schizochytrium sp. S31 via combinational control strategy of “glucose sufficient-periodic dissolved oxygen concentration operation”[J]. Food and Fermentation Industries, 2022
, 48(18)
: 101
-106
.
DOI: 10.13995/j.cnki.11-1802/ts.032158
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