Soybean Protein Research Articles

Structural and Thermal Aggregation Behaviors of Soybean Protein in View of Subunits: A Mini-Review

Structural and Thermal Aggregation Behaviors of Soybean Protein in View of Subunits: A Mini-Review

Glycine soja, PI424025, is a valuable genetic resource to improve soybean seed-protein content and composition.

Soybean seed-protein content and composition is important because it contributes over half the value of this $61 billion crop. Historic negative correlation between seed-protein content and oil have been reported. Similarly, negative correlation between seed-protein content and yield have been reported but may be at least in part mitigated by increasing the genetic diversity of the elite soybean germplasm. Improvements in amino acid composition of seed-protein would increase the value of soybean meal and protein for animal and human consumption. We have identified a genetic resource in wild soybean germplasm, PI424025B, with elevated seed-protein, elevated cysteine in the seed and increased sulfur content in the seed. We have developed a population of Recombinant Inbred Lines derived from a cross between NC-Raleigh and PI424025B. We evaluated the carbon, nitrogen and sulfur (C, N and S) content of seeds from the progeny, the parents and other high-seed protein soybean lines. N content and C/N (ratio of C to N) were well correlated with protein content measured by NIR. PI424025B had a N content comparable to high-protein soybean lines and a superior N/S. These traits were inherited by some of the progeny. Quantitative Trait Loci (QTL) associated with high-seed protein were identified on chr2, chr20 and chr15 and colocalizes with well characterized loci on chr 15 and chr 20 known to affect seed-protein content and quality. A potentially unique QTL was identified on Chr15. Unlike the chr20 QTL, the chr15 QTL improved S content relative to N content and was superior to other high seed-protein phenotypes tested. These data indicate that PI424025B is a valuable resource to diversify the genetics of soybean while improving soybean seed-protein content and composition.

Conformational and processing properties of a high-active ingredient involving soy protein isolates bound with anthocyanins and its application in cake baking

Soybean protein is of plant origin and is commonly appropriate for improving the processing characteristics of foods. This study aimed to explore a novel functional ingredient that contained soybean protein isolate (SPI) and blueberry anthocyanins (BANs). The spatial conformation and secondary structure of SPI-BANs complexes were analyzed using circular dichroism and fluorescence spectroscopy, the processing properties were investigated as well as the retention of antioxidant activity during thermal treatments. Results showed that the contents of free sulfhydryl and free amino groups in complexes increased to 3.50 and 1.19 folds than those of SPI, respectively, while the surface hydrophobicity decreased by 74.23%. Compared with SPI, the BANs-modified SPI had a smaller particle size of 29.12 nm and a lower zeta-potential of -8.73 mV and on the other hand, the complexes possessed higher solubility (83.08%) and foaming and emulsifying properties (115.08% and 54.03 m2/g). After fortification with SPI-BANs, the baking loss rate and adhesiveness of chiffon cake were reduced by 10.82% and improved to 0.24 N.mm, respectively. The high antioxidant activities of SPI-BANs under heat led to the cake’s bioactivities largely enhanced by 1.99 ~ 12.71 folds, being 345.19 µg Trolox/g for the DPPH radical scavenging activity. This study developed the functional food ingredients as antioxidants and a substitute for animal-based proteins in bakery products, which was safe and sustainable by using the dietary components from plant resources.Graphical

Using Egg Parasitoids to Manage Caterpillars in Soybean and Maize: Benefits, Challenges, and Major Recommendations

The use of egg parasitoids in Augmentative Biological Control (ABC) is a highly effective strategy within the integrated pest management (IPM) of lepidopteran defoliators. Safer than chemical insecticides, these natural antagonists have demonstrated significant efficacy. Trichogramma pretiosum and Telenomus remus, known for their high parasitism rates, are the most extensively used and studied parasitoids for controlling economically important lepidopterous in crops such as soybean and maize. Brazil, a leading adopter of crops expressing Bacillus thuringiensis (Bt) proteins, faces growing field-evolved resistance to Cry proteins in soybean and maize. This resistance, particularly of Rachiplusia nu in soybean and Spodoptera frugiperda in maize, has become more prominent in recent years, increasing insecticide use. Therefore, this article reviews the current status of egg parasitoids adoption in ABC against lepidopteran pests, emphasizing the role of Tr. pretiosum and the potential of Te. remus as sustainable alternatives to chemical insecticides to manage pests in both non-Bt and Bt crops. Additionally, we provide recommendations for using these parasitoids in ABC programs and discuss the challenges that must be addressed to optimize the adoption of biocontrol agents in ABC programs for maximum benefit.

Dairy and nondairy proteins as nano-architecture structures for delivering phenolic compounds: Unraveling their molecular interactions to maximize health benefits.

Phenolic compounds are recognized for their benefits against degenerative diseases. Clinical and nutritional applications are limited by their low solubility, stability, and bioavailability, compromising their efficacy. Natural macromolecules, such as lipids, polysaccharides, and proteins, employed as delivery systems can efficiently overcome these limitations. In this sense, proteins are attractive due to their biocompatibility and dynamic structure properties, functional adaptability and self-assembly capabilities, offering stability, efficient encapsulation, and controlled release. This review explores the potential use of dairy proteins, caseins, and whey proteins, and, alternatively, nondairy proteins, gelatin, human serum albumin, maize zein, and soybean proteins, in building wall materials for the delivery of phenolic compounds. To optimize performance, aspects, such as protein-phenolic affinity and complex stability/activity, should be considered when designing particle nano-architecture. Molecular interactions between protein-phenolic compound complexes are, thus, further discussed, as well as the effects of temperature and pH and strategies to stabilize and preserve nano-architecture and retain phenolic compound activity. All proteins harbor one or more putative binding sites, shared or not, depending on the phenolic compound. Preservation techniques are still a case-to-case study, as no behavior patterns among different complexes are noted. Safety aspects necessary for the marketing of nanoproducts, such as characterization, toxicity assessments, and post-market monitoring as defined by the European Food Safety Authority and the Food and Drug Administration, are discussed, evidencing the need for a unified regulation. This review broadens our understanding and opens new opportunities for the development of novel protein-based nanocarriers to obtain more effective and stable products, enhancing phenolic compound delivery and health benefits.

Ultrasonication coupled to enzymatic hydrolysis of soybean okara proteins for producing bioactive and bioavailable peptides

This work was aimed to explore the antioxidative properties, bioavailability and the safety of bioactive peptides obtained by the enzymatic hydrolysis of ultrasound-treated (UO) and untreated (nUO) soybean okara proteins. Particularly, the peptidomic profiles of both hydrolysates were examined using an untargeted metabolomics technique for suspect screening that was specifically designed for the profiling of short-chain peptides and relied on ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) and bioinformatics.Next, both UO and nUO hydrolysates reduce Dipeptidyl peptidase-IV (DPP-IV) enzyme activity until 39.54 ± 0.26 % and 43.29 ± 0.36 % respectively and inhibit angiotensin converting enzyme (ACE) activities by 30.54 ± 0.42 % and 30.76 ± 0.02 %, respectively. Moreover, they demonstrate to exerted antioxidant properties. Particularly, they show a comparable in vitro antioxidant activity but when the oxidative stress is induced by H2O2 in Caco-2 cells, UO hydrolysate is more active in lowering the levels of reactive oxygen species (ROS) and of lipid peroxidation induced of 48% and 20% respectively.In addition, UO- and nUO-derived peptides trans-epithelial transported by human differentiated intestinal cell monolayer, were identified. Lastly, the possible hepatotoxicity of UO and nUO hydrolysates in HepG2 cells has not been observed by measuring alanine transferase (ALT) and aspartate transferase (AST) levels and cytotoxic effects.

Fabrication and characterization of curcumin-encapsulated composite nanoparticles based on soybean protein isolate hydrolysate/soybean polysaccharides: Interaction mechanism, stability and controlled release properties

This study developed a stable nanoparticle (CUR-SPIH/SSPS) using soybean protein isolate hydrolysate (SPIH) and soybean polysaccharides (SPSS) to protect curcumin (CUR) from degradation during storage and exposure to light and heat conditions, achieving controlled release. The SPIH to SPSS mass ratio of 5:1 gave the CUR-SPIH/SPSS nanoparticles with the highest CUR encapsulation efficiency (95.60 ± 3.00 %) and the strongest antioxidant capacity (90.26 ± 2.42 % and 66.78 ± 1.89 % for ABTS•+ and DPPH radical scavenging ability, respectively), and CUR was successfully encapsulated within the CUR-SPIH/SPSS as evidenced by X-ray diffraction. FTIR and fluorescence spectroscopy analysis confirmed that the interactions in CUR-SPIH/SPSS are primarily driven by electrostatic, hydrogen bonding, and hydrophobic interactions. Moreover, the CUR-SPIH/SPSS nanoparticles significantly enhanced CUR's thermal and UV light stability. The UV degradation kinetics showed that the half-life of CUR-SPIH/SPSS (247.55 min) was 1.61 times longer than that of free CUR (154.03 min). The release rate of CUR incorporated into CUR-SPIH/SPSS was significantly delayed during in vitro gastrointestinal digestion. This study introduces an innovative nanoparticle strategy for the stable delivery of lipophilic compounds.

A comparative study of different soybean oil forms on the physicochemical properties of surimi myofibrillar protein gel: The role of soybean protein isolate and κ-carrageenan

Natural soybean oil, Pickering emulsion, high-internal-phase emulsion (HIPE), and emulsion gel were prepared to investigate their effects on the physicochemical properties of surimi myofibrillar protein gels. Their effects on gel strength ranked as: emulsion gel > Pickering emulsion > HIPE > soybean oil. At the same oil content, the emulsion gel exhibited higher G' than the other forms whereas natural oil exhibited the lowest G', and T22 was smaller in the emulsion gel group, indicating that the emulsion gel enhanced the interaction between water molecules and protein macromolecules. FT-IR testified that 9 % natural oil reduced the β-sheet content to 26.34 %, whereas Pickering emulsion, HIPE, and emulsion gel recovered the β-sheet content to 31.30 %, 36.17 %, and 32.69 %, respectively. Emulsion gel led to fewer voids, and the oil droplets in emulsion gel were more regularly spherical and homogeneously dispersed in the gel matrix, which might be attributed to the filling effects as well as “bridging action” of soybean protein isolate and κ-carrageenan within surimi proteins. In conclusion, we demonstrated emulsion gel as a good replacer to mitigate the negative effect of oil on the texture and structure of surimi gels, which would be a promising approach for oil supplementation in surimi production.

Effect of limited hydrolysis on the structure and gel properties of soybean isolate proteins: A comparative study of papain or/and trypsin

Plant protein's gelation is crucial in various food applications, and hydrolysis may enhance their gelation properties. In this study, we prepared soybean protein isolate hydrolysates (SPIH) using trypsin and/or papain, and found significant improvement in the solubility and gelling properties. These proteases broken down the peptide bonds and caused the exposure of hydrophobic groups as well as the unfolding of protein. Low molecular weight (<35 kDa) SPIHs were generated by the two-step enzymatic hydrolysis, showing significant improvements in storage modulus (G′), loss modulus (G″), viscosity, strength, and water-holding capacity (WHC). Among, PT-10 exhibited the highest WHC (61.72 ± 0.36 %), gel strength (4.67 ± 0.12 g), and network cross-linking density (0.33 ± 0.01 mol/m3), while its solubility was also significantly increased up to 254 %. According to the results of gel molecular force interactions, disulfide bonds, hydrophobic interactions and hydrogen bonds involved in the gel network formation. These findings reveal that the appropriate hydrolysis modification may improve SPI gel's properties and expand its application in gel foods.

Utilization of soybean protein isolate hydrolysates as carriers: Improved encapsulation efficiency and stability of curcumin

This study aimed to explore the potential of soybean protein isolate hydrolysates (SPIH) prepared via Alcalase as delivery carriers and develop novel SPIH-Cur nanoparticles. Hydrolysis caused the varying degrees degradation in the 7S and 11S subunits, significantly enhancing SPI's antioxidant activity. The reduction in particle size and the exposure of hydrophobic groups in SPIH contributed to the formation of stable SPIH-Cur nanoparticles, due to their well binding capacity to curcumin (Cur). The 30 min SPIH-Cur sample exhibited the highest encapsulation efficiency (83.09 %), owing to its high binding affinity (Ka = 9.56 × 103 M−1). Encapsulation by SPIH also significantly improved Cur's thermal and light stability. Moreover, FTIR, fluorescence spectra, and molecular docking analyses revealed that the formation of SPIH-Cur were primarily driven by hydrophobic forces and hydrogen bonds. Above results provide a foundation for fabricating nanoparticles that deliver lipophilic bioactive compounds with high encapsulation efficiency and stability derived from SPIH.

Production of nattokinase and γ-polyglutamic acid via soybean whey fermentation by Bacillus subtilis BSNK-5 and their emulsification to form nanoemulsions

Soybean whey, a nutrient-rich byproduct generated during the production of soybean protein isolate, can only be discharged after undergoing sewage treatment, which imposes a significant economic burden on enterprises. In this study, we investigated a Bacillus subtilis BSNK-5 fermentation soybean whey process that yielded high production of nattokinase (NK) and γ-polyglutamic acid (γ-PGA), along with the fabrication of an emulsion using fermentation soybean whey, to achieve high-value conversion of soybean whey. The results showed that soybean whey can be used as a nutrient-rich substrate to promote the efficient synthesis of NK and γ-PGA by BSNK-5, with the highest yields of 9 × 104 IU/mL and 250 g/L, respectively. Meanwhile, the synthesized γ-PGA can serve as a suitable biological macromolecule to form an emulsification system that protects NK. The encapsulation efficiency of NK was over 60%, and the release of encapsulated NK was delayed in vitro. Meanwhile, the nanoemulsions remained stable when exposed to 37°C and 65°C temperatures, salt concentrations ranging from 50-150 mM, and undergoing a single freeze-thaw cycle. The development of functional thrombolytic preparations by self-emulsification protection of NK by γ-PGA produced via BSNK-5 fermentation represents an effective way to achieve high value utilization of soybean whey.

Soy protein gels based on ultrasonic treatment: Effects of Ca2+ and 11S/7S ratio on gel structures and digestive properties

This study aimed to explore the impact of varying Ca2+ concentrations and 11S/7S ratios on the gel performance of soybean protein gels (SPGs) under ultrasonication (400 W, 15 min) and to clarify the mechanisms involved. Results showed Ca2+ addition altered the structure of soybean 11S/7S protein gels. Low Ca2+ levels increased the turbidity, hardness, and water retention of the gels, whereas high levels disrupted the orderly aggregation of 11S/7S proteins, creating a rough, porous network. The effect of Ca2+ was more pronounced with a higher 11S ratio, significantly influencing turbidity, disulfide bonding, and gel hardness. Conversely, 7S-rich gels showed reduced sensitivity to Ca2+. In vitro digestion and SDS-PAGE results indicated that 7S globulin’s α, α’, and β subunits were more digestible than the A and B subunits of 11S globulin. In conclusion, ultrasound combined with Ca2+ can enhance the cross-linking degree between 11S and 7S globulin, forming a dense network structure.

Structural and physicochemical properties of plant-based meat analogues from transglutaminase-modified soybean protein

Plant-based meat analogues (PBMA) have been developed for decades. The resemblance in PBMA to meat, in terms of physical properties and sensory attributes, is important for consumers. This study aims to investigate the effects of transglutaminase (TG) concentration (1, 3, 5% (w/w)) on modified textured vegetable soybean protein (TVP). The changes in TVP protein molecular weight, microstructure, texture profile, sensory quality and nutritional value of PBMA were investigated. The first set of analyses examined the impact of TG concentration on TVP structure and the results showed that the TVP protein band from SDS-PAGE were changed to a larger band at 36-40 kDa as compared to the control indicating the formation of a cross-linked protein. The modified TVP was used as a raw ingredient for PBMA development. The appearance and microstructure of PBMA from the TG-modified TVP showed that the uncooked PBMA with TG-modified TVP were not different from those of the control. With regard to the texture profile of PBMA, an increase in TG concentration resulted in an increase in hardness. A sensory evaluation revealed that the PBMA with 1%TG provided the highest overall acceptance score. Hence, the PBMA with 1%TG was selected for a nutritional analysis comparing steak to meat. The carbohydrate and fat content of PBMA with 1%TG were higher than those of meat while the protein content of PBMA with 1%TG consisted of a maximum of 70% meat. This research could lead to alternative plant-based foods in the food industry.

The Effect of Dihydromyricetin (DMY) on the Mechanism of Soy Protein Isolate/Inulin/Dihydromyricetin Interaction: Structural, Interfacial, and Functional Properties.

The combination of proteins with polysaccharides and polyphenols is expected to improve their physicochemical and functional properties. In this study, a novel plant-based antioxidant emulsifier was formed by soybean protein isolate (SPI), inulin (INU), and dihydromyricetin (DMY). Based on the binary system of SPI/INU, we focused on exploring the effect of the DMY concentration (0.5 mg/mL~2.5 mg/mL) on the formation and properties of the ternary complex. The structure, interaction mechanism, and interfacial and functional properties of the ternary complex were investigated. The results indicate that compared to the SPI/INU binary complex, the SPI/INU/DMY ternary complex had a significant decrease in particle size (~100 nm) and a slight decrease in absolute zeta potential. The SPI/INU binary complex with DMY mainly interacted by hydrogen bonding and hydrophobic interactions. Due to the incorporation of DMY, the structure of SI was denser and more flexible. The ternary complex exhibited an ideal three-phase contact angle and demonstrated better foaming and antioxidant ability. Additionally, compared to SPI/INU, the ternary complex had a significant improvement in EAI. These results provide a strategy for polyphenols to modify the structure, interfacial properties, and functions of protein/polysaccharide complexes. This provides a potential reference for the preparation of more ternary complexes with excellent emulsifying and antioxidant properties for application in emulsions.

Research Progress on Tofu Coagulants and Their Coagulation Mechanisms.

Tofu has captivated researchers' attention due to its distinctive texture and enrichment in nutritional elements, predominantly soybean protein. Coagulants play a critical role in promoting coagulation during tofu production, directly influencing its texture, quality, and physicochemical characteristics. Currently, the impact of coagulant characteristics on coagulation, as well as the underlying mechanisms, remain unclear. This review provides a summary of research progress on salt coagulants, acid coagulants, enzyme coagulants, novel coagulants, polysaccharide additives, and various coagulant formulations. The coagulation mechanisms of various coagulants are also discussed. Accordingly, this paper seeks to offer reliable theoretical guidance for the development of novel coagulants and the realization of fully automated tofu production.

Graph-Root: Prediction of Root-Associated Proteins in Maize, Sorghum, And Soybean Based on Graph Convolutional Network and Network Embedding Method

Background: The root system plays an irreplaceable role in plant growth. Its improvement can increase crop productivity. However, such a system is still mysterious for us. The underlying mechanism has not been fully uncovered. The investigation on proteins related to the root system is an important means to complete this task. In the previous time, lack of root-related proteins makes it impossible to adopt machine learning methods for designing efficient models for the discovery of novel root-related proteins. Recently, a public database on root-related proteins was set up and machine learning methods can be applied in this field. Objective: The purpose of this study was to design an efficient computational method to predict root-associated proteins in three plants: maize, sorghum, and soybean. Method: In this study, we proposed a machine learning based model, named Graph-Root, for the identification of root-related proteins in maize, sorghum, and soybean. The features derived from protein sequences, functional domains, and one network were extracted, where the first type of features were processed by graph convolutional neural network and multi-head attention, the second type of features reflected the essential functions of proteins, and the third type of features abstracted the linkage between proteins. These features were fed into the fully connected layer to make predictions. Results: The 5-fold cross-validation and independent tests suggested its acceptable performance. It also outperformed the only previous model, SVM-Root. Furthermore, the importance of each feature type and component in the proposed model was investigated. Conclusion: Graph-Root had a good performance and can be a useful tool to identify novel rootrelated proteins. BLOSUM62 features were found to be important in determining root-related proteins.

High-level secretory expression and characterization of an acid protease in Komagataella phaffii and its application in soybean meal protein degradation

Acid proteases play a crucial role in the industrial enzyme market, but low yield limits their widespread application. In this study, we focused on enhancing the secretory expression level of an acid protease (AopepA) from Aspergillus oryzae in Komagataella phaffii through stepwise genetic modification strategies. These included the co-expression of endoplasmic reticulum secretion-associated factors, overexpression of eukaryotic translation initiation factors, knockout of the β-1,3-glucanosyltransferase gene, disruption of the hypoxic heme-dependent repressor gene, and co-expression of the hemoglobin gene. After these modifications, protease activity increased by 4.2-fold, reaching 536.6 U/mL in a shaking flask. The engineered strain produced protease activity of up to 17,392.0 U/mL with a protein concentration of 44.6 g/L in a 5 L fermenter, representing the highest secretory expression level of acid proteases in K. phaffii ever reported. The optimal conditions of AopepA were pH 3.0 and 50 °C. AopepA demonstrated broad hydrolysis activity towards various protein substrates. It efficiently degraded soybean meal proteins into low molecular weight (Mw < 1 kDa, accounting for 82 %) oligopeptides to enhance protein utilization. This study provides valuable insights into improving the secretory expression of acid proteases in K. phaffii and identifies a suitable acid protease for enhancing soybean meal protein utilization.

Comparative study of physicochemical and structural properties of plant proteins hydrolyzed by different

This study used trypsin to hydrolyze soybean protein isolate (SPI), Cyperus esculentus protein (CEP), Wheat gluten protein (WGP), and flaxseed protein (FP) to varying extents, comparing the structure and physicochemical properties of four plant proteins as well as their enzymatic hydrolysates. Results indicate SPI's surface hydrophobicity rises with hydrolysis, whereas CEP's decreases. Additionally, all four plant proteins exhibit improved essential amino acid content and oil-holding capacity as hydrolysis progresses. The CEP with a 20% degree of hydrolysis achieved the optimal oil holding capacity, reaching 10.2 g/g. SPI demonstrated superior foam capacity. As the degree of hydrolysis increased, foam stability varied among the four proteins. The CEP hydrolyzed to 10% exhibited the highest emulsifying activity index, achiving a value of 60 m2/g. Additionally, the emulsifying stability index of CEP hydrolysates significantly improved as the degree of hydrolysis increased. According to the DPPH• assay, both CEP and their enzymatic hydrolysate had the highest free radical scavenging rate. These findings provided a theoretical basis and empirical evidence for the use and adaptation of plant protein hydrolysates as a promising and environmentally sustainable source of plant-derived peptides in food processing reaprocessing.

Effects of soybean insoluble dietary fiber and CaCl2 on the structure and properties of low-moisture extruded products.

Texturized vegetable protein is currently a leading alternative to animal meat. This study examined the effects of soybean insoluble dietary fiber (SIDF) (0% to 20%) and CaCl2 (0% to 1%) on the structure and properties of extruded products made from a soybean protein isolate-wheat gluten (SPI-WG) composite. The study showed that SIDF (4% to 8%) increased the viscosity of extruded products, enhanced their specific mechanical energy, and improved their rehydration rate and tensile strength compared with a control group. The rehydration rate of the extruded products reached a maximum value of 331.67% in the 8% SIDF, 0.5% CaCl2 groups. The addition of excess SIDF prevented the cross-linking of protein molecules to form a loose network structure. Analysis of the infrared spectrum and intermolecular forces showed that physical interactions between fibers and proteins were the dominant forces, with hydrophobic interactions and hydrogen bonds primarily maintaining the structure of the extruded products. The addition of CaCl2 (0.5%) led to protein aggregation and further improved the rehydration and tensile strength of extruded products. Soybean insoluble dietary fiber can improve the rehydration rate and quality of extruded products. The addition of CaCl2 mitigated the weakening of the protein structure caused by excess SIDF. These results provide a basis for the improvement of the quality of low-moisture-extruded texturized vegetable protein products with a high dietary fiber concentration and a high rehydration rate. © 2024 Society of Chemical Industry.

Pilot-scale bioremediation of rare earths wastewater by Chlamydomonas sp. YC

The extraction of rare earth elements (REEs) through in-situ leaching with ammonium sulphate [(NH4)2SO4] had resulted in the production of a large volume of ammonium-rich wastewater, causing severe environmental pollution. This study aimed to assess the ability of an indigenous microalga Chlamydomonas sp. YC, isolated from REEs wastewater, to directly treat real REEs wastewater under outdoor conditions in 50 L airlift photobioreactors (AL-PBRs) and 5.0 m3 open race-way photobioreactors (ORWPs). Additionally, the harvested Chlamydomonas sp. YC biomasses from these two pilot photobioreactors were comprehensively analyzed to evaluate the nutritional values. The results showed that Chlamydomonas sp. YC in AL-PBRs exhibited higher biomass production (1.1 g/L), greater removal efficiencies in NH4+-N (24.9%) and total nitrogen (20.4%), as well as higher CO2 fixation rate (125.0 mg/(L·d)), compared to those of ORWPs. Moreover, the Chlamydomonas sp. YC biomasses obtained from the two pilot photobioreactors contained 44.5% and 49.4% protein, 9.1% and 14.3% lipids. Moreover, Chlamydomonas sp. YC in the two pilot photobioreactors displayed essential amino acid indexes (EAAI) of 0.900, which was higher than that of soybean protein (0.657), indicating superior nutritional values. In conclusion, the implementation of the process involving Chlamydomonas sp. YC in AL-PBRs under outdoor conditions holds promise as a coupled microalgal biotechnology for the simultaneous removal of NH4+-N from REEs wastewater, and the capture of CO2 for the production of valuable biomass.