Abstract
Marine heterotrophic dinoflagellate Crypthecodinium cohnii is an aerobic oleaginous microorganism that accumulates intracellular lipid with high content of 4,7,10,13,16,19-docosahexaenoic acid (DHA), a polyunsaturated ω−3 (22:6) fatty acid with multiple health benefits. C. cohnii can grow on glucose and ethanol, but not on sucrose or fructose. For conversion of sucrose-containing renewables to C. cohnii DHA, we investigated a syntrophic process, involving immobilized cells of ethanologenic bacterium Zymomonas mobilis for fermenting sucrose to ethanol. The non-respiring, NADH dehydrogenase-deficient Z. mobilis strain Zm6-ndh, with high ethanol yield both under anaerobic and aerobic conditions, was taken as the genetic background for inactivation of levansucrase (sacB). SacB mutation eliminated the levan-forming activity on sucrose. The double mutant Zm6-ndh-sacB cells were immobilized in Ca alginate, and applied for syntrophic conversion of sucrose to DHA of C. cohnii, either taking the ethanol-containing fermentation medium from the immobilized Z. mobilis for feeding to the C. cohnii fed-batch culture, or directly coculturing the immobilized Zm6-ndh-sacB with C. cohnii on sucrose. Both modes of cultivation produced C. cohnii CCMP 316 biomass with DHA content around 2–3 % of cell dry weight, corresponding to previously reported results for this strain on glucose.
Original language | English |
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Pages (from-to) | 63-70 |
Number of pages | 8 |
Journal | Journal of Biotechnology |
Volume | 338 |
DOIs | |
Publication status | Published - 10 Sept 2021 |
Externally published | Yes |
Keywords*
- Crypthecodinium cohnii
- Docosahexanoic acid
- Immobilized cells
- Levansucrase
- Syntrophy
- Zymomonas mobilis
Field of Science*
- 1.6 Biological sciences
- 1.4 Chemical sciences
Publication Type*
- 1.1. Scientific article indexed in Web of Science and/or Scopus database