Simultaneous production of DHA and squalene from Aurantiochytrium sp. grown on forest biomass hydrolysates

Abstract

BackgroundRecent evidence points to the nutritional importance of docosahexaenoic acid (DHA) in the human diet. Thraustochytrids are heterotrophic marine oleaginous microorganisms capable of synthesizing high amounts of DHA, as well as other nutraceutical compounds such as squalene, in their cellular compartment. Squalene is a natural triterpene and an important biosynthetic precursor to all human steroids. It has a wide range of applications in the cosmetic and pharmaceutical industries, with benefits that include boosting immunity and antioxidant activity. Apart from its nutritional quality, it can also be utilized for high-grade bio-jet fuel by catalytic conversion.ResultsIn the present study, the potential of thraustochytrid strain Aurantiochytrium sp. T66 to produce DHA and squalene was evaluated. When the strain was cultivated on organosolv-pretreated birch hydrolysate (30 g/L glucose) in flask, it resulted in 10.39 g/L of cell dry weight and 4.98 g/L of total lipids, of which 25.98% was DHA. In contrast, when the strain was grown in a bioreactor, cell dry weight, total lipid, and DHA increased to 11.24 g/L, 5.90 g/L, and 35.76%, respectively. The maximum squalene yield was 69.31 mg/gCDW (0.72 g/L) when the strain was cultivated in flask, but it increased to 88.47 mg/gCDW (1.0 g/L), when cultivation shifted to a bioreactor.ConclusionsThis is the first report demonstrating the utilization of low cost non-edible lignocellulosic feedstock to cultivate the marine oleaginous microorganism Aurantiochytrium sp. for the production of nutraceutical vital compounds. Owing to the simultaneous generation of DHA and squalene, the strain is suitable for industrial-scale production of nutraceuticals.

Co-production of DHA and squalene by thraustochytrid from forest biomass

“…Medium pH was adjusted to 6.8 with 1 N HCl before sterilization. The content of artificial seawater was similar as reported in our previous studies 68 . with the 100 mL of working solution.…”

An Overview of Potential Oleaginous Microorganisms and Their Role in Biodiesel and Omega-3 Fatty Acid-Based Industries

“…T66 (ATCC PRA-276) in heterotrophic cultivation using forest biomass hydrolysates (30 g/L glucose) in flasks. The study obtained results of cell dry weight and total lipids of 10.39 g/L and 4.98 g/L, respectively, of which 25.98% constituted of DHA [23]. In the same work, Aurantiochytrium sp.…”

“…In the same work, Aurantiochytrium sp. T66 was also cultivated in a bioreactor and resulted in elevated values for the cell dry weight (11.24 g/L), total lipid (5.90 g/L), and DHA content (35.76% of the total lipids) [23], enabling a better process control. These results indicate the great potential in valorizing sustainable resources for the production of DHA.…”

“…After accessing the fatty acid profiles, the lipid obtained from various oleaginous microorganisms was deemed not suitable for biodiesel feedstock due to the high proportion of PUFA in their total lipid content [21]. These PUFA with more than two double bonds are readily susceptible to autooxidation that makes biodiesel technically unsatisfactory, with unpleasant odor [22,23]. Many of the fatty acids can be synthesized in human bodies; however, there is a group of PUFA such as docosahexaenoic acid (DHA) and as eicosapentaenoic acid (EPA) that cannot be synthesized by human beings due to lack of some desaturases and elongases that take part in the synthesis of EPA and DHA from parent omega-3 fatty acids such as α-linolenic acid (C 18:3 n−3, ALA) [24].…”

Enigmatic Microalgae from Aeroterrestrial and Extreme Habitats in Cosmetics: The Potential of the Untapped Natural Sources

“…These microalgae belong to the stramenopilic group of thraustochytrids (alternatively classified as fungi or algae) which inhabit marine and freshwaters, but also mud and decaying mangrove leaves [181,182]. Besides squalene, thraustochytrids produce other valuable lipids such as PUFAs, and docosahexaenoic acid (DHA) in particular [183,184]. The commercial interest in thraustochytrids is based on their ability to accumulate lipids faster than any other oleaginous microorganisms [185].…”