Reduced IgE and IgG antigenic response to milk proteins hydrolysates obtained with the use of non-commercial serine protease from Yarrowia lipolytica

Exploring proteolytic activity of Lactiplantibacillus plantarum AHQ-14 reducing the allergenicity of milk protein and its probiotic potential based on peptidomics and genomics

In our previous work, Lactiplantibacillus plantarum AHQ-14 was isolated from the conventional fermented dairy products in Xinjiang district (China) for its strong ability to reduce the antigenicity of bovine milk β-LG. Although its probiotic properties and safety were evaluated in vitro, it is necessary to further explore the effect of L. plantarum AHQ-14 on the major allergenic proteins and its mechanism of action and probiotic potential by peptidomics and genomics in this study. The results showed that the hydrolysis ability of L. plantarum AHQ-14 to α-LA, β-LG, and α-CN was the strongest at 10 h of incubation, and their Ig E binding inhibition rates were also higher. Peptidomics results showed that L. plantarum AHQ-14 could destroy the main allergic epitopes of α-LA, β-LG, α-CN, and obtain a variety of bioactive peptides. Genomics results revealed L. plantarum AHQ-14 contained a great deal of genes encoding a phosphoenolpyruvate-dependent glucose phosphate transport system, a complete Opp oligopeptide transport system, and abundant peptidase-related genes, and indicated that L. plantarum AHQ-14 had a strong ability to metabolize and transport carbohydrates and AA, as well as strong hydrolyze proteins. Lactiplantibacillus plantarum AHQ-14 also had probiotic potential in pathogen defense and immune stimulation, and strong environmental adaptability. This study laid a foundation for the practical utilization of L. plantarum AHQ-14 and the further development of other probiotics with potential to reduce allergenicity of proteins.

Modeling Tool for Studying the Influence of Operating Conditions on the Enzymatic Hydrolysis of Milk Proteins

Systematic modeling of the enzymatic hydrolysis of milk proteins is needed to assist the study and production of partially hydrolyzed milk. The enzymatic hydrolysis of milk proteins was characterized and evaluated as a function of the temperature and protease concentration using Alcalase, Neutrase and Protamex. Modeling was based on the combination of two empirical models formed by a logarithmic and a polynomial equation to correlate the kinetic constants and the operating conditions. The logarithmic equation fitted with high accuracy to the experimental hydrolysis curves with the three proteases (R2 > 0.99). The kinetic constants were correlated with the operating conditions (R2 > 0.97) using polynomial equations. The temperature and protease concentration significantly affected the initial rate of hydrolysis, i.e., the kinetic constant a, while the kinetic constant b was not significantly affected. The values for the kinetic constant a were predicted according to the operating conditions and they were strongly correlated with the experimental data (R2 = 0.95). The model allowed for a high-quality prediction of the hydrolysis curves of milk proteins. This modeling tool can be used in future research to test the correlation between the degree of hydrolysis and the functional properties of milk hydrolysates.

Use of Yarrowia lipolytica to Obtain Fish Waste Functional Hydrolysates Rich in Flavoring Compounds

Fishery processing industries generate large amounts of by-products. These by-products come from fish heads, skin, bones, thorns, and viscera. The disposal of these wastes represents an increasing environmental and health problem. Nowadays, there is a growing interest in how to utilize fish materials that are not used for human consumption. Among the different solutions proposed, the use of proteolytic and lipolytic microorganisms represents a green solution for waste valorization. In this work, first we screened several conventional and non-conventional microorganisms for their proteolytic and lipolytic functions. Then, the most promising strains (Yarrowia lipolytica YL2, Y. lipolytica YL4, Bacillus amyloliquefaciens B5M and B. subtilis B5C) were tested on a fish waste-based solution. After 72 h incubation at room temperature, the supernatants obtained using the strains of Y. lipolytica showed the highest degree of hydrolysis (10.03 and 11.80%, respectively, for YL2 and YL4), the strongest antioxidant activity (86.4% in DPPH assay for YL2) and the highest formation of aldehydes (above 50% of the total volatile compounds detected). Hydrolysates of fish waste obtained with Y. lipolytica may be reused in feed and food formulations for their functional and flavoring characteristics.

Alteration of the allergenicity of cow's milk proteins using different food processing modifications

Milk is an essential source of protein for infants and young children. At the same time, cow's milk is also one of the most common allergenic foods causing food allergies in children. Recently, cow's milk allergy (CMA) has become a common public health issue worldwide. Modern food processing technologies have been developed to reduce the allergenicity of milk proteins and improve the quality of life of patients with CMA. In this review, we summarize the main allergens in cow's milk, and introduce the recent findings on CMA responses. Moreover, the reduced effects and underlying mechanisms of different food processing techniques (such as heating, high pressure, γ-ray irradiation, ultrasound irradiation, hydrolysis, glycosylation, etc.) on the allergenicity of cow's milk proteins, and the application of processed cow's milk in clinical studies, are discussed. In addition, we describe the changes of nutritional value in cow's milk treated by different food processing technologies. This review provides an in-depth understanding of the allergenicity reduction of cow's milk proteins by various food processing techniques.

Valorization of by-products from vegetable oil industries: Enzymes production by Yarrowia lipolytica through solid state fermentation

Vegetable oil extraction generates high amounts of by-products, which are designated as oil cakes. Since the current strategies employed for oil cakes' reuse are linked with some drawbacks, identification of alternative approaches to decrease the environmental impact and promote a circular economy is of vital importance. In general, these materials are characterized by high fiber content, making them suitable to be employed in solid state fermentation (SSF). Filamentous fungi have been the microorganisms mostly applied in SSF and yeasts were applied in less extent. In the present work, three by-products from the extraction of olive, sunflower, and rapeseed oils were used as solid substrates in SSF for lipase and protease production by Yarrowia lipolytica W29. Oil cakes mixtures composition was optimized for the production of each enzyme using a simplex-centroid design of experiments. A 50% (w/w) mixture of olive cake (OC) and sunflower cake (SC) led to the highest lipase production, while a combination of the three oil cakes was most suitable for maximum protease production. Both enzymes were produced at maximum levels in a short period of 48 h. This work demonstrated that enzyme production by Y. lipolytica W29 in SSF can be modulated by the different combinations of oil cakes in the substrate mixture. Additionally, the potential of using by-products from vegetable oil industries in SSF processes was also demonstrated, showing alternative strategies for their valorization.

Milk protein hydrolysates obtained with immobilized alcalase and neutrase on magnetite nanoparticles: Characterization and antigenicity study

Enzymatic hydrolysis is the most commonly used method to reduce the antigenicity of milk protein, but free protease is unstable and difficult to recycle after application. In this study, alcalase and neutrase were selected for immobilization on the modified magnetic Fe₃ O₄ nanoparticles. The reusability of the immobilized enzyme was 68.23% of the total starting activity after 5 recycling batches. The optimal hydrolysis conditions were an enzyme to substrate ratio of 6000 U/g and reaction at 50℃ and pH 8.5 for 3 h. Under these conditions, 22.76% hydrolysis of hydrolysate was achieved, and the antigenicity reduction rates of β-lactoglobulin and casein were 21.34% and 30.89%, respectively. In addition, 82.75% of the hydrolysate had a molecular weight less than 1 kDa, and free amino acids represented 13.65% of the sample. This result showed that the hydrolysis with immobilized enzyme was similar to that with free enzyme and the immobilized enzyme could be applied to produce hypoallergenic hydrolysate. PRACTICAL APPLICATION: Reduces milk protein allergenicity.

Purification and Characterization of the Protease from Staphylococcus xylosus A2 Isolated from Harbin Dry Sausages

The protease generated from Staphylococcus (S.) xylosus A2, which was isolated from Harbin dry sausages, was purified and characterized. The molecular weight of the purified protease was approximately 21.5 kDa, and its relative activity reached the highest at pH 6.0 and 50 °C. At pH 4.0−8.0 and temperatures of 20−50 °C, the protease was stable. Its activity was significantly improved by Ca2+ and Zn2+ ions (p < 0.05). The Michaelis constant and maximum velocity of the protease were 2.94 mg/mL and 19.45 U/mL·min, respectively. The thermodynamic parameters analysis suggested that the protease showed better catalytic properties at 40 °C. Moreover, the protease could hydrolyze meat proteins, and obtained hydrolysate is non-cytotoxic to the HEK-293 cells. These findings provide a theoretical basis for understanding the enzymatic characterization of S. xylosus A2 protease and its future application in fermented meat products.

Simultaneous hydrolysis of various protein-rich industrial wastes by a naturally evolved protease from tannery wastewater microbiota

Elimination of protein-rich waste materials is one of the vital environmental protection requirements. Using of non-naturally occurring chemicals for their remediation properties can potentially induce new pollutants. Therefore, enzymes encoded in the genomes of microorganisms evolved in the same environment can be considered suitable alternatives to chemicals. Identification of efficient proteases that can hydrolyze recalcitrant, protein-rich wastes produced by various industrial processes has been widely welcomed as an eco-friendly waste management strategy. In this direction, we attempted to screen a thermo-halo-alkali-stable metagenome-derived protease (PersiProtease1) from tannery wastewater. The PersiProtease1 exhibited high pH stability over a wide range and at 1 h in pH 11.0 maintained 87.59% activity. The enzyme possessed high thermal stability while retaining 76.64% activity after 1 h at 90 °C. Moreover, 65.34% of the initial activity of the enzyme remained in the presence of 6 M NaCl, showing tolerance against high salinity. The presence of various metal ions, inhibitors, and organic solvents did not remarkably inhibit the activity of the discovered protease. The PersiProtease1 was extracted from the tannery wastewater microbiota and efficiently applied for biodegradation of real sample tannery wastewater protein, chicken feathers, whey protein, dehairing sheepskins, and waste X-ray films. PersiProtease1 proved its enormous potential in simultaneous biodegradation of solid and liquid protein-rich industrial wastes based on the results.

Yarrowia lipolytica, health benefits for animals

The yeast Yarrowia lipolytica has been industrially adopted for docosahexaenoic acid and eicosapentaenoic acid production under good manufacturing practices over 2 decades. In recent years, it has claimed attention for novel biotechnological applications, such as a functional feed additive for animals. Studies have demonstrated that this yeast is safe and has probiotic and nutritional properties for mammals, birds, fish, crustaceans, and molluscs. Animals fed Y. lipolytica enhanced productive and immune parameters, as well as modulated microbiome, fatty acid composition, and biochemical profiles. Additionally, some Y. lipolytica-derived compounds have improved productive performance, immune status, and disease resistance in animals. Therefore, the aim of this review is to identify and discuss research advances on the potential use of this yeast for animals of economic interest. Challenges, opportunities, and trends were identified and envisioned in the near future for this industrially produced yeast. KEY POINTS: • Yarrowia lipolytica has probiotic and nutritional effects in animals. • Lipase2, EPA, and β-glucan from Y. lipolytica have health benefits for animals. • Y. lipolytica is envisioned in terrestrial and aquatic animal production systems.

Highly Effective, Regiospecific Hydrogenation of Methoxychalcone by Yarrowia lipolytica Enables Production of Food Sweeteners

We describe the impact of the number and location of methoxy groups in the structure of chalcones on the speed and efficiency of their transformation by unconventional yeast strains. The effect of substrate concentration on the conversion efficiency in the culture of the Yarrowia lipolytica KCh 71 strain was tested. In the culture of this strain, monomethoxychalcones (2′-hydroxy-2″-, 3″- and 4″-methoxychalcone) were effectively hydrogenated at over 40% to the specific dihydrochalcones at a concentration of 0.5 g/L of medium after just 1 h of incubation. A conversion rate of over 40% was also observed for concentrations of these compounds of 1 g/L of medium after three hours of transformation. As the number of methoxy substituents increases in the chalcone substrate, the rate and efficiency of transformation to dihydrochalcones decreased. The only exception was 2′-hydroxy-2″,5″-dimethoxychalcone, which was transformed into dihydrochalcone by strain KCh71 with a yield comparable to that of chalcone containing a single methoxy group.

Effect of ultrasonic-ionic liquid pretreatment on the hydrolysis degree and antigenicity of enzymatic hydrolysates from whey protein

With the aim to reduce the antigenicity of whey protein hydrolysate in milk, the pretreatment method of coupling ultrasonic and ionic liquid (US-IL) and further enzymatic treatments were studied. Papain and alcalase were found to be suitable for ultrasonic-ionic liquid pretreatment. After ultrasound-ionic liquid treatment, the antigenic decline rates of ALA and BLG upon alcalase hydrolysis were 82.82% and 88.01%, and that of the papain hydrolysis was 81.87% and 88.46%, respectively. Upon ultrasonic-ionic liquid pretreatment, the molecular weight of whey protein did not change significantly, but the small molecular weight proportion of components in the enzymatic hydrolysate obviously increased. The findings showed that combining with US-IL pretreatment for further protease hydrolysis of whey proteins, the hydrolysate can be used in order to produce hypoallergenic bovine whey proteins.