Over the last several decades, concerns about climate change and pollution due to human activity has gained widespread attention. Microalgae have been proposed as a suitable biological platform to reduce carbon dioxide, a major greenhouse gas, while also creating commercial sources of high-value compounds such as medicines, cosmetics, food, feed, and biofuel. Industrialization of microalgae culture and valorization is still limited by significant challenges in scaling up the production processes due to economic constraints and productivity capacities. Therefore, a boost in resource usage efficiency is required. This enhancement not only lowers manufacturing costs but also enhancing the long-term viability of microalgae-based products. Using wastewater as a nutrient source is a great way to reduce manufacturing costs. Furthermore, water scarcity is one of the most important global challenges. In recent decades, industrialization, globalization, and population growth have all impacted freshwater resources. Moreover, high amounts of organic and inorganic toxins in the water due to the disposal of waste into rivers can have severe impacts on human and animal health. Microalgae cultures are a sustainable solution to tertiary and quaternary treatments since they have the ability to digest complex contaminants. This review presents biorefineries based on microalgae from all angles, including the potential for environmental pollution remediation as well as applications for bioenergy and value-added biomolecule production. An overview of current information about microalgae-based technology and a discussion of the associated hazards and opportunities for the bioeconomy are highlighted.

The oil processing industry generates significant quantities of lemon basil seed residue which is not currently used to any significant extent. However, this by-product has important potential as a source of bioactive peptides which may play a role as ingredients in functional foods. This study therefore sought to optimize the preparation techniques used to obtain the necessary protein hydrolysate from de-fatted lemon basil seeds (DLBS), and subsequently to examine the ACE inhibitory capabilities of the resulting hydrolysate. Response Surface Methodology (RSM) was used for the hydrolysis of DLBS by Alcalase®, with observation of the resulting ACE inhibitory activity and degree of hydrolysis (DH). The optimum conditions were 55 °C and 103 minutes with a ratio of enzyme to substrate of 7.0% w/v. The hydrolysate was fractionated by ultrafiltration and purified through RP-HPLC. The results reveal that the F₂ sub-fraction demonstrated the highest ACE inhibitory activity. The amino acid sequence of this peak was identified by mass spectrometry as LGRNLPPI and GPAGPAGL with a molecular weight of 879.06 and 639.347 Dalton, respectively. These peptides were classified as non-toxic and bitter peptides. For the synthesized version of these peptides, the ACE inhibitory activity values, measured by IC₅₀, were 0.124 ± 0.02 mM and 0.013 ± 0.001 mM, respectively. Analysis of the Lineweaver–Burk plot confirmed that these peptides served as non-competitive ones. The study of molecular docking showed that the ACE inhibitory behavior of both purified peptides was mainly due to the interactions of the hydrogen bonds between the peptides and ACE. It is therefore suggested that DLBS may be a useful raw material allowing the production of antihypertensive peptides which can offer therapeutic and commercial benefits as an ingredient in functional foods.

Angiotensin converting enzyme (ACE) inhibition offers a useful means of managing hypertension, because ACE inhibitors (ACEIs) are known to serve as agents with antihypertensive properties in addition to generating positive metabolic and cardioprotective outcomes. However, current ACEIs are linked to adverse consequences, and so there is a requirement for effective but safer compounds, which might be achieved through chemical synthesis or the isolation of naturally obtained bioactive molecules. Protein hydrolysates with ACEI activity can be produced by the combined pepsin and pancreatin proteolysis (to mimic gastrointestinal digestion) of longan seed protein. This study examined longan seed protein hydrolysates, obtained from a sequential 3 h digestion with pepsin and then pancreatin. The resulting hydrolysate underwent sequential ultrafiltration membrane fractionation with a 10, 5, and 3 kDa molecular weight cut-off (MWCO). The permeate derived from the <3 kDa MWCO demonstrated the highest ACEI activity. This permeate subsequently underwent separation by reverse-phase high performance liquid chromatography to give the main fractions on the basis of differing elution times. The ACEI IC₅₀ values for these fractions were then identified. Quadrupole time-of-flight tandem mass spectrometry was employed to determine the peptide mass for the major peak (F₅), which was shown to be Glu–Thr–Ser–Gly–Met–Lys–Pro–Thr–Glu–Leu (ETSGMKPTEL) and Ile–Ser–Ser–Met–Gly–Ile–Leu–Val–Cys–Leu (ISSMGILVCL). These two peptides were stable over a temperature and pH range of −20 to 90 °C and 2–12, respectively, for 60 min. From the Lineweaver–Burk plot, both peptides inhibited ACE non-competitively. Molecular docking simulation of the peptides with ACE supported the formation of hydrogen bonds by the peptides with the ACE active pockets. This research indicates that it may be possible to use both of these peptides or longan seed protein hydrolysates in order to create ingredients for functional foods, or to produce pharmaceutical products, capable of lowering hypertension.

The Synechococcus sp. VDW peptides were prepared by trypsin digestion, which was then purified by ultrafiltration with molecular weight cut off membranes of 10, 5 and 3 kDa. Among the fractions, the MW <3 kDa fraction exhibited high levels of inhibitory activity toward the NO radical scavenging activities with IC₅₀ values of 34.51 ± 9.8 μg/mL. The MW <3 kDa fraction was purified by reversed-phase HPLC to yield four fractions. The 30–40 min sub-fraction with maximum NO radical scavenging activity (77.50 ± 0.55%) was selected for further analysis by Q-TOF ESI mass spectrometry. Five isolated peptides with amino acid sequences of AILQSYSAGKTK; 1,265.69 Da, ALNKTHLIQTK; 1,265.74 Da, LLVHAPVK; 875.55 Da, IPDAHPVK; 875.48 Da, and VVVLRDGAVQQLGTPR; 1,706.97 Da were identified. The MW <3 kDa fraction showed no cytotoxicity toward RAW264.7 macrophage cells. Quantitative RT-PCR results showed that the MW <3 kDa fraction reduced gene expression of pro-inflammatory cytokines iNOS, TNF-α, COX-2, and IL-6. The peptides isolated from the MW <3 kDa fractions represent potential model peptides to develop natural anti-inflammation food-grade ingredients, drugs, and cosmetic products.

This research examined the antioxidant abilities of peptides derived from the Hericium erinaceus mushroom produced via three microbial proteases (Alcalase®, Neutrase®, and Flavourzyme®) at varying concentrations of 10, 25, and 50 mg mL⁻¹. The H. erinaceus mushroom hydrolysate produced from 10 mg mL⁻¹ Alcalase® with 4 hours’ digestion resulted in the highest levels of 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazl (DPPH), and nitric oxide (NO) radical scavenging activities. Fractionation of this particular hydrolysate was then performed by ultrafiltration (10, 5, 3, and 0.65 kDa molecular weight cut-off membranes). The MW < 0.65 kDa fraction demonstrated the highest level of radical scavenging activity in the context of ABTS, DPPH, and NO. Therefore, the fraction MW < 0.65 kDa was performed with RP-HPLC to obtain the four principal fractions termed F_1–4. The results reveal that the F₄ sub-fraction demonstrated the best radical scavenging ability. Additionally, the F₄ sub-fraction was able to reduce the potential for DNA damage caused by hydroxyl radicals. This was revealed by testing using the Fenton reaction and the pUC19, pKS, and pBR322 plasmids. This outcome was demonstrated through in vitro antiproliferative activity in human lung carcinoma cell lines (Chago-K1) using MTT assay. The F₄ sub-fraction was also demonstrated to induce apoptosis, as indicated using the FITC Annexin V apoptosis detection kit with PI. Furthermore, it was also found that the activity of caspase-3, -8, and -9 in Chago-K1 cells was enhanced after exposure periods of 24 and 48 hours. Finally, this sub-fraction was selected for peptide sequencing via quadrupole-time-of-flight-electron spin induction-mass spectrometry-based de novo peptide sequencing.