Xiangyu Rui

The production of fucoxanthin and fatty acids in Conticribra weissflogii has been examined, but the role of elements like phosphorus in their mutualistic interactions is not well understood. To fill this gap, our study utilized potassium dihydrogen phosphate (KH₂PO₄) as a source of phosphorus to examine its impact on the synthesis of fucoxanthin and fatty acids in C. weissflogii. Our findings revealed that at a phosphorus concentration of 10 mg L⁻¹, the cell density (9.5 × 10⁵ cells mL⁻¹), carotenoid concentration (1.67 mg g⁻¹), fucoxanthin concentration (0.91 mg L⁻¹), and fucoxanthin content (1.33 mg g⁻¹) were maximized. Additionally, at a phosphorus concentration of 20 mg L⁻¹, cell dry weight (0.76 ± 0.08 g L⁻¹), total fatty acid content, saturated fatty acids, and unsaturated fatty acids were all at their highest levels, making this concentration optimal for EPA accumulation. In conclusion, manipulating the phosphorus concentration can enhance the levels of fucoxanthin and unsaturated fatty acids in C. weissflogii, offering valuable insights into the co-production of these two high-value compounds within this species.

Enhancing microalgal growth and bioactive compound production is becoming a duty for improving photosynthetic microorganisms. In this study, the growth, carotenoid, and fatty acid profiles of Conticribra weissflogii were studied under four different silicate concentrations and silicate-deficient conditions in an f/2 medium with continuous aeration, light intensity (30 ± 2 µmol m⁻² s⁻¹), salinity (25 ± 2‰), pH (8), and temperature (25 ± 2 °C). At the end of the experiment, we observed that a silicate concentration of 120 mg L⁻¹ produced the maximum biomass dry weight (0.86 g L⁻¹), carotenoid content (1.63 µg mL⁻¹), and fucoxanthin content (1.23 mg g⁻¹) in C. weissflogii. The eicosapentaenoic acid (EPA) (11,354.37 µg g⁻¹), docosahexaenoic acid (DHA) (2516.16 µg g⁻¹), gamma-linolenic acid (C18:3n6) (533.51 µg g⁻¹), and arachidonic acid (C20:4n6) (1261.83 µg g⁻¹) contents were significantly higher at Si 120 mg L⁻¹. The results further showed the maximum fatty acid content in C. weissflogii at Si 120 mg L⁻¹. However, the silicate-deficient conditions (Si 0 mg L⁻¹) resulted in higher levels of saturated fatty acids (38,038.62 µg g⁻¹). This study presents a practical approach for the large-scale optimization of biomass, carotenoid, fucoxanthin, and fatty acid production in C. weissflogii for commercial purposes.

The production of fucoxanthin and fatty acids in Conticribra weissflogii has been examined, but there is still a lack of understanding regarding the impact of trace elements, including iron, on their co-production. To address this knowledge gap, this study investigated the effects of FeCl₃·6H₂O on the growth, fucoxanthin, and fatty acids of C. weissflogii. The findings revealed that the highest cell density (1.9 × 10⁶ cells mL⁻¹), cell dry weight (0.89 ± 0.15 g L⁻¹), and total fatty acid concentration (83,318.13 µg g⁻¹) were achieved at an iron concentration of 15.75 mg L⁻¹, while the maximum carotenoid and fucoxanthin contents were obtained at an iron concentration of 3.15 mg L⁻¹. The study demonstrated that the content of the active substance in C. weissflogii could be increased by adjusting the iron concentration, providing new information as to the more efficient co-production of fucoxanthin and fatty acids and offering experimental support for large-scale production.

Fucoxanthin is a natural active substance derived from diatoms that is beneficial to the growth and immunity of humans and aquatic animals. Temperature, light and salinity are important environmental factors affecting the accumulation of diatom actives; however, their effects on the production of fucoxanthin in C. weissflogii are unclear. In this study, single-factor experiments are designed and followed by an orthogonal experiment to determine the optimal combination of fucoxanthin production conditions in C. weissflogii. The results showed that the optimum conditions for fucoxanthin production were a temperature of 30 °C, a light intensity of 30 umol m⁻² s⁻¹ and a salinity of 25. Under these conditions, the cell density, biomass, carotenoid content and fucoxanthin content of C. weissflogii reached 1.97 × 10⁶ cell mL⁻¹, 0.76 g L⁻¹, 2.209 mg L⁻¹ and 1.372 mg g⁻¹, respectively, which were increased to 1.53, 1.71, 2.50 and 1.48 times higher than their initial content. The work sought to give useful information that will lead to an improved understanding of the effective method of cultivation of C. weissflogii for natural fucoxanthin production.

Fucoxanthin and fatty acids are active substances that are beneficial to the growth and immunity of humans and aquatic animals. However, relatively few species have been exploited for fucoxanthin and fatty acids in the industry. At the same time, due to its low extract content, poor stability, high production cost, and serious seasonal and regional limitations, the industry cannot normally meet the greater demand of the international market. Therefore, this experiment seeks to improve the fucoxanthin and fatty acid content of C. weissflogii by adjusting the nitrogen concentration in the culture medium. It was found that when the nitrogen concentration was 150 mg L⁻¹, the cell number was 1.5 × 10⁶ cell mL⁻¹, and the average biomass was 0.75 g L⁻¹. The mean value of carotenoid concentration was 2.179 mg L⁻¹. The average concentration of fucoxanthin was 1.547 mg g⁻¹. When the nitrogen concentration was 75 mg L⁻¹, the fatty acid content reached its highest. By adjusting the concentration of nitrogen, the contents of fucoxanthin and fatty acids were increased. The results provided a theoretical basis for commercial extraction of fucoxanthin and fatty acids and further promoted the industrialization of fucoxanthin and fatty acids.