Different fermentation strategies by Schizochytrium mangrovei strain pq6 to produce feedstock for exploitation of squalene and omega‐3 fatty acids

Abstract

Schizochytrium mangrovei strain PQ6 was investigated for coproduction of docosahexaenoic acid (C22: 6ω-3, DHA) and squalene using a 30-L bioreactor with a working volume of 15 L under various batch and fed-batch fermentation process regimes. The fed-batch process was a more efficient cultivation strategy for achieving higher biomass production rich in DHA and squalene. The final biomass, total lipid, unsaponifiable lipid content, and DHA productivity were 105.25 g · L , 43.40% of dry cell weight, 8.58% total lipid, and 61.66 mg · g · L , respectively, after a 96 h fed-batch fermentation. The squalene content was highest at 48 h after feeding glucose (98.07 mg · g of lipid). Differences in lipid accumulation during fermentation were correlated with changes in ultrastructure using transmission electron microscopy and Nile Red staining of cells. The results may be of relevance to industrial-scale coproduction of DHA and squalene in heterotrophic marine microalgae such as Schizochytrium.

Engineering Strategies in Microorganisms for the Enhanced Production of Squalene: Advances, Challenges and Opportunities

“…Many studies have confirmed that Aurantiochytrium sp. could accumulate a considerable amount of squalene (Jiang et al, 2004; Chen et al, 2010; Fan et al, 2010; Kaya et al, 2011; Hoang et al, 2014, 2018; Nakazawa et al, 2014). In a patent (WO/2012/159979) registered for discovering a process for producing squalene from the microalgal species Thraustochytriales , claimed that by providing an enriched medium with vitamins B 12 , B 1 and/or B 6 at 30°C temperature, squalene titre could be obtained between 20 and 120 mg/g DCW (Pora et al, 2014).…”

“…In the experiment, a squalene content of 33 mg/g DCW was recovered for both cases, while the yields reached 0.99 and 1.01 g/L, respectively (Hoang et al, 2014). Recently, this strain was analyzed for different fermentation conditions, wherein the maximum squalene content (98.07 mg/g of lipid) was attained after 48 h of incubation in a 15 L medium containing 22% glucose (Hoang et al, 2018). High squalene producing novel yeast-like fungus strain Pseudozyma SD301 has also been isolated.…”

Lab-Scale Optimization of Aurantiochytrium sp. Culture Medium for Improved Growth and DHA Production

“…In the first trial, this basal medium was compared to MT1, a culture medium that was designed in accordance with the information available in the literature [2,6,10,11,14,17,20,[26][27][28][29][30][31][32][33][34]. The MT1 medium was tested using two trace metals solutions: (i) TM1, the trace metals solution of MB10; and (ii) TM2, formulated based on previous results obtained in the literature [6,8,10,14,16,17,20,24,26,27,[32][33][34][35].…”

“…DHA belongs to a class of LC-PUFA often called "omega-3 fatty acids", which are in high demand due to the many known benefits in nutrition. DHA is also widely known for its fundamental role in preventing cardiovascular diseases, being essential for brain and eye development (particularly in children), learning capacities, as well as for the prevention of neurodegenerative conditions, arthritis, asthma and skin diseases [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. In addition, DHA plays a key role in membrane fluidity, cell signaling, cell interactions and in the development of the immune system and inflammatory responses [21][22][23].…”

“…Nevertheless, several sustainability problems are strongly related to fish oil, namely overfishing and chemical products used in the extraction of this oil [4,7,14,17,20,24]. In addition, fish oil is associated with an unpleasant smell, taste, low DHA amount, and possible presence of harmful contaminants, due to ocean pollution and bioaccumulation of heavy metals, dioxins and polychlorinated biphenyls [7,14,16,17,20,24,25]. Moreover, the increasing need for food and the spread of aquaculture worldwide will also require higher amounts of these oils for aquafeed.…”