Diana Fimbres-Olivarría

Aquaculture faces significant challenges, including water pollution and low productivity in traditional systems. Biofloc technology (BFT) offers a sustainable alternative by recycling nutrients and improving water quality. The present study assessed the efficacy of bioflocs enriched with the freshwater microalgae such as Chlorella sorokiniana and Scenedesmus sp. in Nile tilapia ( Oreochromis niloticus ) culture. Four treatments were tested; the biofloc systems were inoculated with i) control group without microalgae inoculation, ii) C. sorokiniana in an initial density of 1 × 10 ⁶ cells/mL, iii) Scenedesmus sp. (1 × 10 ⁶ cells/mL), and iv) mixed culture (1 × 10 ⁶ cells/mL for each species). Growth performance, proximal composition of bioflocs, hematological parameters, and water quality were analyzed. Results demonstrated that treatment with C. sorokiniana achieved the highest biomass (6.9 × 10 ⁶ cells/mL) compared to the treatment with Scenedesmus sp., (2.8 × 10 ⁶ cells/mL) as well as better nutritional composition in C. sorokiniana treatment. Tilapia reared in the C. sorokiniana biofloc system showed significantly higher final body weight (63.51 g), weight gain (WG; 55.77 g), specific growth rate (SGR; 3.01% day ⁻¹ ), and improved feed utilization ( p < 0.05) compared to the control and other treatments. This treatment also optimized water quality, reducing nitrite levels to 2.68 mg/L, compared to 4.27 mg/L in the control group. Hematological parameters did not differ significantly among treatments, indicating no adverse physiological effects. The mixed algae biofloc treatment yielded no synergistic benefits, likely due to interspecies competition. Overall, the incorporation of C. sorokiniana ‐enriched bioflocs significantly enhances tilapia performance and water quality, demonstrating their potential for sustainable aquaculture.

Diseases caused by oxidative stress can present different susceptibilities depending on blood typing according to the ABO system and RhD factor, which turn out to be of great clinical importance. The use of antioxidants such as C-phycocyanin (a phycobiliprotein) could be an alternative to mitigate oxidative stress in the blood. Therefore, the objective of this study is to evaluate the antioxidant and erythroprotective activity of C-phycocyanin (C-PC) from Spirulina sp. against oxidative stress caused by peroxyl radicals, before and after in vitro digestion, comparing susceptibilities between blood groups. C-phycocyanin from Spirulina sp. was obtained commercially. The antioxidant capacity by ABTS+•, DPPH•, and FRAP assays of the bioaccessible fraction of C-PC increased compared to baseline in all assays. Samples appear to have high hydrogen atom transfer. C-PC is not cytotoxic in most blood groups. The AAPH hemolysis assays showed differences between blood groups, yielding results of 27.90, 22.60, 26.94, 27.66, 28.16, 28.34, and 24.91% hemolysis for O+, O−, A+, A−, B+, AB+, and AB−, respectively. Furthermore, in vitro digestion increased the erythroprotective effect in the bioavailable fraction in most blood groups, showing 37.12, 80.13, 5.48, 92.38, 67.93, 80.30, and 76.49% inhibition of hemolysis in O+, O−, A+, A−, B+, AB+, and AB−, respectively. These results demonstrate the biotechnological and biomedical potential of phycobiliproteins as safe candidates for the development of nutraceuticals and functional foods aimed at preventing oxidative damage.

Blood groups in the ABO system and the RhD factor is of great clinical importance, as it is related to susceptibility to various diseases caused by oxidative stress. The use of antioxidants such as C-phycocyanin (a phycobiliprotein) could be an alternative to mit-igate oxidative stress in the blood. Therefore, the objective of this study is to evaluate the antioxidant and erythroprotective activity of C-phycocyanin (C-PC) from Spirulina sp. against oxidative stress caused by peroxyl radicals, before and after in vitro digestion, comparing susceptibilities between blood groups. C-phycocyanin from Spirulina sp. was obtained commercially. The antioxidant capacity by ABTS+•, DPPH•, and FRAP assays of the bioaccessible fraction of C-PC increased compared to baseline in all assays. Samples appear to have high hydrogen atom transfer. C-PC is not cytotoxic in most blood groups. The AAPH hemolysis assays showed differences between blood groups, yielding results of 27.90, 22.60, 26.94, 27.66, 28.16, 28.34, and 24.91% hemolysis for O+, O-, A+, A-, B+, AB+, and AB-, respectively. Furthermore, in vitro digestion increased the erythropro-tective effect in the bioavailable fraction in most blood groups, showing 37.12, 80.13, 5.48, 92.38, 67.93, 80.30, and 76.49% inhibition of hemolysis in O+, O-, A+, A-, B+, AB+, and AB-, respectively. These results demonstrate the biotechnological and biomedical po-tential of phycobiliproteins as safe candidates for the development of nutraceuticals and functional foods aimed at preventing oxidative damage.

The nanoencapsulation of bioactive compounds such as β-carotene and microalgal extracts has emerged as an effective strategy to enhance their stability, bioavailability, and biological efficacy, particularly against oxidative stress. Dunaliella tertiolecta, a microalga rich in carotenoids and chlorophylls, presents notable antioxidant and erythroprotective properties; however, its bioactive potential is limited by low bioaccessibility and degradation during processing and digestion. This study aimed to develop and evaluate nanoliposomes loaded with D. tertiolecta extract and β-carotene as sustained-release systems to improve antioxidant performance and erythroprotective effects. The methodology involved optimizing microalgal cultivation under nitrogen and salinity stress to enhance pigment accumulation, followed by extraction, nanoencapsulation via the particle dispersion method, and physicochemical characterization of the nanoliposomes. Antioxidant capacity and release kinetics were assessed through ABTS and FRAP assays, while erythroprotective activity was evaluated by monitoring oxidative hemolysis in human erythrocytes. The release kinetics revealed an anomalous transport mechanism for both systems, with β-carotene showing faster and more efficient release due to its greater lipophilic compatibility with the nanoliposomal matrix. The nanoliposomal systems demonstrated nanoscale size, high encapsulation efficiency, sustained antioxidant release, and effective erythrocyte protection, with the extract-loaded formulation exhibiting synergistic effects superior to isolated β-carotene. These findings support the potential application of this nanotechnology-based delivery system in functional foods, nutraceuticals, and biomedical formulations aimed at preventing oxidative stress-related cellular damage.

The nanoencapsulation of bioactive compounds such as β-carotene and microalgal extracts has emerged as an effective strategy to enhance their stability, bioavailability, and biological efficacy. Dunaliella tertiolecta, a microalga rich in carotenoids and chlorophylls, presents notable antioxidant and erythroprotective properties; however, its bioactive potential is limited by low bioaccessibility and degradation during processing and digestion. This study aimed to develop and evaluate nanoliposomes loaded with D. terti-olecta extract and β-carotene as sustained-release systems to improve antioxidant performance and erythroprotective effects. The methodology involved optimizing microalgal cultivation under nitrogen and salinity stress to enhance pigment accumulation, followed by extraction, nanoencapsulation via the particle dispersion method, and physicochemical characterization of the nanoliposomes. Antioxidant capacity and release kinetics were assessed through ABTS and FRAP assays, while erythroprotective activity was evaluated by monitoring oxidative hemolysis in human erythrocytes. The release kinetics revealed an anomalous transport mechanism for both systems, with β-carotene showing faster and more efficient release due to its greater lipophilic compatibility with the nanoliposomal matrix. The nanoliposomal systems demonstrated nanoscale size, high encapsulation efficiency, sustained antioxidant release, and effective erythrocyte protection, with the extract-loaded formulation exhibiting synergistic effects superior to isolated β-carotene. These findings support the potential application of this nanotechnology-based delivery system in functional foods, nutraceuticals, and biomedical formulations aimed at preventing oxidative stress-related cellular damage.

Nanoliposomes have increased exponentially since their discovery in the 1960s, primarily for encapsulating medicines or compounds that can improve human health. However, recent studies propose nanoliposomes as vehicles to protect, transport, and subsequently release compounds of various kinds to fortify the properties of foods and cause a prolonged release of encapsulated substances in a specific part of the body. Among the compounds successfully encapsulated are β-carotene; α-carotene; vitamins A, C, and D; and lycopene, among others. The encapsulation of extracts with high contents of antioxidant pigments is still to be explored. Therefore, this review aims to compile the compounds that have been successfully encapsulated and have met the specific prolonged release criteria, highlighting areas of research opportunity and application such as biomedical, pharmaceutical, and nutraceutical industries.

The use of nano-liposomes has increased exponentially since their discovery in the 1960s, primarily for encapsulating medicines or compounds that can improve human health. However, recent studies propose nano-liposomes as vehicles to protect, transport, and subsequently release compounds of various kinds to fortify the properties of foods and cause a prolonged release of encapsulated substances in a specific part of the body. Among the compounds successfully encapsulated are β-carotene, α-carotene, vitamins A, C, and D, lycopene, among others. The encapsulation of extracts with high contents of antioxidant pigments is still to be explored. Therefore, this review aims to compile the compounds that have been successfully encapsulated and have met the specific prolonged release criteria, highlighting areas of research opportunity and application such as biomedical, pharmaceuticals and nutraceutical industries.

Amphora aff. amoena and Chaetoceros muelleri are potential diatoms with good proximal composition and the ability to grow rapidly. Like other microalgae, this composition can be improved by adjusting their culture conditions, such as exposure to different light conditions. However, there is still a need to explore these culture conditions further and their effect on these diatoms. This study aimed to evaluate the chemical-proximal composition of the diatoms A. aff. amoena and C. muelleri under three wavelengths: white (WL) range (400-750 nm), blue (BL) range (430-480 nm), and red (RL) range (595-660 nm), at an irradiance of 200 μmol m-2 s-1 using LED lights. In both species, A. aff. amoena and C. muelleri, the highest cell concentration under WL was: 216,250 and 1,198,125 cells mL-1, respectively. The carbohydrate content was 5.80% for A. aff. amoena and 2.21% for C. muelleri, while protein content was 13.41% for A. aff amoena and 12.31% for C. muelleri. Lipids were found to be most abundant in A. aff. amoena when exposed to RL (37.19%) and C. muelleri (60.48%) when exposed to BL. No significant differences were found in A. aff. amoena under different light conditions.

Marine algae are a valuable source of polysaccharides. However, the information available on sulfated polysaccharides from microalgae is limited. Navicula sp. is a microalga present in the Sea of Cortez, of which little is known regarding their polysaccharides’ properties. This study investigated the physicochemical and microstructural characteristics of Navicula sp. sulfated polysaccharide (NSP). The Fourier transform infrared spectrum of NSP showed distinctive bands (1225 and 820 cm⁻¹, assigned to S–O and C–O–S stretching, respectively), confirming the molecular identity. NSP registered molecular weight, intrinsic viscosity, a radius of gyration, and a hydrodynamic radius of 1650 kDa, 197 mL/g, 61 nm, and 36 nm, respectively. The zeta potential, electrophoretic mobility, conductivity, and diffusion coefficient of the molecule were −5.8 mV, −0.45 µm cm/s V, 0.70 mS/cm, and 2.9 × 10⁻⁹ cm²/s, respectively. The characteristic ratio and persistence length calculated for NSP were 4.2 and 1.3 nm, suggesting a nonstiff polysaccharide chain conformation. The Mark–Houwink–Sakurada α and K constants were 0.5 and 1.67 × 10⁻¹, respectively, indicating a molecular random coil structure. NSP scanning electron microscopy revealed a rough and porous surface. Knowing these polysaccharides’ physicochemical and microstructural characteristics can be the starting point for elucidating their structure–function relationship as a valuable tool in advanced biomaterial design.