Caseinolytic Activity Research Articles

ISOLATION AND CHARACTERIZATION OF PROTEASE FROM WISTERIA SINENSIS AND CHLORIS BARBATA

Enzymes, as biocatalysts, have extensive industrial applications. Protease enzymes, in particular, are widely used in industries such as leather, detergents, food, pharmaceuticals, and diagnostics. Alkaline proteases, which require a neutral to alkaline pH for activity, are notably sourced from plants. Objective: This study aimed to isolate and partially purify protease enzymes from the leaves of Wisteria sinensis and Chloris barbata, and to characterize their enzymatic properties, particularly their caseinolytic activity in alkaline conditions. Methods: Proteases were isolated and partially purified from the leaves of Wisteria sinensis and Chloris barbata. Enzyme kinetics were assessed to determine the optimal caseinolytic activity of the proteases. The study focused on evaluating the enzymes' stability at specific pH levels and temperatures. Statistical analysis was conducted to compare the enzymatic activities and to validate the findings. Results: The isolated proteases from both Wisteria sinensis and Chloris barbata demonstrated optimal caseinolytic activity in alkaline pH. The enzymes exhibited significant stability across specific pH levels and temperatures, confirming their alkaline nature. These findings highlight the potential industrial applications of these proteases. Conclusion: The study provides valuable insights into the isolation and characterization of proteases from Wisteria sinensis and Chloris barbata. The identified alkaline proteases show promise as industrial biocatalysts due to their stability and significant protease activity. Further research is warranted to purify these enzymes fully and explore their specific industrial applications, emphasizing the biotechnological potential of diverse plant sources.

Production of milk-coagulating protease by fungus Pleurotus djamor through solid state fermentation using wheat bran as the low-cost substrate

Proteases are enzymes that hydrolyze peptide bonds present in proteins and peptides. They are widely used for various industrial applications, such as in the detergent, food, and dairy industries. Cheese is one of the most important products of the dairy industry, and the coagulation stage is crucial during the cheese-making process. Enzymatic coagulation is the most common technique utilized for this purpose. Microbial enzymes are frequently used for coagulation due to their advantages in terms of availability, sustainability, quality control, product variety, and compliance with dietary and cultural/religious requirements. In the present study, we identified and subsequently characterized milk coagulant activity from the fungus Pleurotus djamor PLO13, obtained during a solid-state fermentation process, using the agro-industrial residue, wheat bran, as the fermentation medium. Maximum enzyme production and caseinolytic activity occurred 120 h after cultivation. When the enzyme activity against various protease-specific synthetic substrates and inhibitors was analyzed, the enzyme was found to be a serine protease, similar to elastase 2. This elastase-2-like serine protease was able to coagulate pasteurized whole and reconstituted skim milk highly efficiently in the presence and absence of calcium, even at room temperature. The coagulation process was influenced by factors such as temperature, time, and calcium concentration. We demonstrate here, for the first time, an elastase-2-like enzyme in a microorganism and its potential application in the food industry for cheese production.

Recovery of Proteases and Protease Inhibitors from Ganoderma spp. Cultivated in Amazonian Lignocellulose Wastes.

Ganoderma spp. are a great source of bioactive molecules. The production and recovery of bioactive molecules vary according to strain, growth substrate, and extraction solution. Variations in protease and their inhibitors in basidiomata from a commercial strain (G. lingzhi) and an Amazonian isolate (Ganoderma sp.) cultivated in Amazonian lignocellulosic wastes and extracted with different solutions are plausible and were investigated in our study. Basidiomata from cultivation in substrates based on açaí seed, guaruba-cedro sawdust and three lots of marupá sawdust were submitted to extraction in water, Tris-HCl, and sodium phosphate. Protein content, proteases, and protease inhibitors were estimated through different assays. The samples were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). Tris-HCl provided higher protein extraction from Ganoderma sp. and higher caseinolytic, gelatinolytic, and fibrinolytic activity for G. lingzhi cultivated in açaí. Water extracts of Ganoderma sp., in general, exhibited higher trypsin and papain inhibitor activities compared to G. lingzhi. Extracts in Tris-HCl and sodium phosphate showed more intense protein bands in SDS-- PAGE, highlighting bands of molecular weights around 100, 50, and 30 kDa. FTIR spectra showed patterns for proteins in all extracts, with variation in transmittance according to substrate and extractor. Water extract from Amazonian Ganoderma sp. cultivated in marupá wastes are promising as a source of protease inhibitors, while the Tris-HCL extract of G. lingzhi from açaí cultivation stands out as a source of proteases with fibrinolytic, caseinolytic, and gelatinolytic activities.

Bacteria of Deep-Sea Sediments of the Black Sea Breaking Down Keratin

Down and feather raw materials generated at food processing plants are among the main environmental pollutants. Most enterprises use burial and burning methods to deal with this waste, which negatively affects the environmental situation. The use of enzymatic hydrolysis by decomposer microorganisms is a promising and safe method for processing keratin waste. Earlier, it was shown that bacteria isolated from the bottom sediments of the Black Sea are active producers of elastases, fibrinogenases, and fibrinases. Therefore, the aim of this work was to evaluate the ability of bacteria isolated from the deep-sea sediments of the Black Sea to exhibit other types of proteolytic activity, in particular, to decompose hard-to-reach protein keratin. Меthods. The objects of the study were 20 cultures of bacteria isolated from deep-sea sediments of the Black Sea represented by the genera Bacillus, Metabacillus, Priestia, and Robertmurraya. The cultures were grown under conditions of submerged cultivation at 28 °C, with a nutrient medium stirring rate of 232 rpm for 4 days. For growth, a basic nutrient medium containing 0.5 % defatted chicken feathers as sole sources of carbon and nitrogen was used. The keratinase activity was assessed by UV absorption at 280 nm of hydrolysis products of keratin-containing materials. Protein was determined by the Lowry method, and caseinolytic (total proteolytic) activity was determined by the Anson method. Disulfide reductase activity was measured spectrophotometrically at 412 nm by evaluating the yellow sulfide formed during the reduction of 5,5’-dithiobis-(2-nitrobenzoic acid) (DTNB). Results. It was shown that the cultures of Metabacillus idriensis 2 and Robertmurraya siralis 57, out of twenty studied, did not grow on a nutrient medium with chicken feathers as the only source of carbon and nitrogen. The remaining 18 cultures exhibited varying degrees of keratinase activity (from 3 to 32 U/mL). The highest level of activity is characteristic of the culture Priestia megaterium 035 (32 U/mL). A study of the ability to break down casein showed that the level of total proteolytic (caseinolytic) activity of most cultures ranged from 0.015 U/mL to 0.14 U/mL. The highest total proteolytic activity was demonstrated by Bacillus pumilus A (0.3 U/mL) and Priestia megaterium 55 (0.24 U/mL) cultures, which also demonstrated high keratinase activity. The highest level of disulfide reductase activity was observed in Bacillus pumilus A (63.3 µmol/min), Bacillus subtilis 248 (62.0 µmol/min), and Priestia megaterium 035 (61.3 µmol/min), and the lowest in Bacillus licheniformis 249. Thus, from the deep-sea sediments of the Black Sea, we have isolated a number of active producers of keratinases, representatives of the two genera Bacillus and Priestia, which, after studying their physicochemical and catalytic properties, may turn out to be promising for practical application, in particular in the development of new technologies for the utilization of down and feather poultry farm waste.

Production of Nattokinase from Bacillus amyloliquefaciens MRS18: A Bacterial Strain Isolated from Fermented Beans.

Nattokinase (NK) is a naturally occurring fibrinolytic protease enzyme obtained from the traditional Japanese food called Natto and has several uses in the pharmaceutical and medical industries. Nowadays, the most often used thrombolytic agent in the clinical field is NK, in part because it is less expensive than other thrombolytic medicines. The objective of this study is to investigate the screening, isolation and characterization of the NK enzyme-producing Bacillus strain from fermented Soya beans. The sample of fermented soya beans were tested for the presence of fibrinolytic protease- producing bacteria, followed by the screening, extraction, characterization and clot lysis assays. A total of three isolates were screened for caseinolytic activities by casein hydrolysis assay. Out of those isolates, MRS18 was found to be potent in producing the enzyme proteinase. To determine the taxonomy and phylogeny of these isolates, biochemical and molecular characterization has been carried out. Bacillus amyloliquefaciens MRS18 has been found with the highest caseinolytic activity. The clot lysing ability of the potent strain Bacillus amyloliquefaciens was found to be 61.7% after 120 min, and on further purification, by ammonium sulphate precipitation method, the lysis percentage was found to be 656% after 120 min. From the results of the present study, we concluded that Bacillus amyloliquefaciens isolated from the fermented soya beans produced an NK enzyme that exhibits immense potential to lyse blood clots.

Comparative analysis of enzymatic profiles and biofilm formation in clinical and environmental Candida kefyr isolates

AbstractThe global landscape of Candida infections has seen a significant shift. Previously, Candida albicans was the predominant species. However, there has been an emergence of non‐albicans Candida species, which are often less susceptible to antifungal treatment. Candida kefyr, in particular, has been increasingly associated with infections. This study aimed to investigate the profiles of enzymatic activity and biofilm formation in both clinical and non‐clinical isolates of C. kefyr. A total of 66 C. kefyr isolates were analysed. The activities of proteinase and phospholipase were assessed using bovine serum albumin and egg yolk agar, respectively. Haemolysin, caseinolytic and esterase activities were evaluated using specific methods. Biofilm formation was investigated using crystal violet staining. The findings indicated that biofilm and proteinase activity were detected in 81.8% and 93.9% of all the isolates, respectively. Haemolysin activity was observed with the highest occurrence (95.5%) among normal microbiota isolates. Esterase activity was predominantly identified in dairy samples and was absent in hospital samples. Caseinase production was found with the highest occurrence (18.2%) in normal microbiota and hospital samples. Phospholipase activity was limited, found in only 3% of all the isolates. These findings reveal variations in enzyme activity between clinical and non‐clinical C. kefyr isolates. This sheds light on their pathogenic potential and has implications for therapeutic strategies.

Inhibition of the Naja naja venom toxicity by polymeric nanoparticles loaded with Leucas aspera methanolic extract.

Snakebite is a neglected tropical disease that affects millions of people worldwide. Developing effective treatments can make a significant contribution to global health efforts and public health initiatives. To reduce mortality due to snakebite, there is an immediate need to explore novel and effective treatment methodologies. In that context, nanoparticle-based drug delivery is gaining a lot of attention. Hydrophilic nanoparticles are suitable for the delivery of therapeutic peptides, proteins, and antigens. The present investigation is aimed at evaluating the anti-ophidian potential of the methanolic extract of the ethno-medicinal herb Leucas aspera (Willd.) loaded within chitosan nanoparticles (CNP-LA), against the Indian cobra (Naja naja) venom enzymes. For this purpose, nanoparticles were prepared using the ionic gelation method to enhance the efficacy of the extract. The physicochemical and structural features of nanoparticles were investigated using dynamic light scattering (DLS), Fourier-transform Infrared (FTIR), field emission scanning electron microscopy (FE-SEM), and X-ray diffraction (XRD) techniques. It was found that CNP-LA has an average size of 260nm with a polydispersity index of 0.132 (PDI) and zeta potential of 34.7 mV, with an encapsulation efficiency of 92.46%. The in vitro release study was performed at pH 5.0 and 7.4. Furthermore, in vitro studies indicated that CNP-LA inhibited the phospholipase A2, hemolytic, and caseinolytic activities of Naja naja venom with the percentage inhibition of 92.5%, 83.9%, and 94.5%, respectively. This is the first report on the application of herbal methanolic extract loaded within chitosan nanoparticles for neutralizing snake venom enzymes with increased efficiency.

Скринінг продуцентів протеаз серед представників роду Bacillus, ізольованих з прибережної зони Кінбурнської коси

Protease-producing representatives of Bacillus have been isolated from various environments such as the rhizosphere, soil, sewage, food, waste, and saline environments (sea water, marine sediments, hypersaline lakes, salty food, soda lakes, etc.). However, today, little is known about the characteristics of proteases in representatives of the genus Bacillus, isolated from the coastal and aquatic environments. In this regard, the purpose of this work was to screen for the presence of different types of proteolytic activity in Bacillus cultures isolated from the coastal zone of the Kinburn split. Methods. The objects of the study were 15 cultures (L1-L15), isolated from the dry grass of the coastal zone of the Kinburn spit (Mykolaiv region). The cultures were grown under conditions of deep cultivation at 28 °С, with a mixing speed of the nutrient medium of 230 rpm for 2 days. Methods of determining proteolytic (caseinolytic, elastolytic, fibrinolytic, fibrinogenolytic, and collagenase) activity in the culture liquid supernatant were used. Results. Study of the spectrum of proteolytic activities of 15 strains of Bacillus sp. showed that L9, L1, L2 and L4 exhibited higher levels of proteolytic activity compared to the other strains tested. Bacillus sp. L9 and L2 showed the highest elastase activity (35.80 and 33.80 U/mL, respectively), L1, L2, and L4 − fibrinogenolytic (12.50, 11.20 and 10.33 U/mL, respectively), and L1 and L4 − fibrinolytic (13.00 and 10.90 U/mL, respectively) activity. Conclusions. According to its catalytic properties, a number of representatives of Bacillus sp. isolated from the dry grass of the coastal zone of the Kinburn split may be promising for further research as producers of enzymes with elastotic, fibrinolytic, and fibrinogenolytic activities.

Approaches to Control and Monitor Protease Levels in Chronic Wounds

AbstractSome wounds do not follow the typical healing trajectory and show very little, if any, progress. They dreadfully threaten the patients' quality of life and may even lead to limb amputation and death. Several interrelated systemic and local factors may cause a delay in wound healing. The microenvironment of these wounds can be different from wounds that heal spontaneously or with standard treatment. As discussed in the present work, proteases’ levels or activity can be elevated in some cases of chronic ulcers; infection can aggravate the situation. A detailed overview of the proteases’ effect on wound healing is presented in this work. Assuming untimely or irregularly excessive proteolytic activity plays a pathological role, some researchers targeted attenuation of protease level as a strategy to promote healing. This can be done via different approaches, including physical removal, inhibiting their activity, and controlling their expression directly through gene silencing or indirectly, for instance, by resolving infection. Apart from targeting protease modulation as a therapeutic strategy, many studies have examined the protease state to gain insights into the underlying mechanisms by which a remedy, dressing, or specific therapy has affected the healing process. This study aims to provide an overview of the studies in these two categories. Of course, various proteases are involved in the healing process, but in each study, usually, only one or some of them are investigated; matrix metalloproteinase‐2 (MMP‐2), MMP‐9, and human neutrophil elastase (HNE) are among them. Furthermore, in some cases, cumulative proteolytic activity is evaluated in terms of gelatinolytic, collagenolytic, or caseinolytic activity, which is also absolutely beneficial. Some research groups have considered the potential of proteases as a diagnostic or prognostic biomarker and have tried to develop some sensors or indicators; this topic is also covered in the present work.

Biochemical and toxicological profiles of venoms from an adult female South American bushmaster (Lachesis muta rhombeata) and her offspring

In this work, we compared the biochemical and toxicological profiles of venoms from an adult female specimen of Lachesis muta rhombeata (South American bushmaster) and her seven offspring born in captivity, based on SDS-PAGE, RP-HPLC, enzymatic, coagulant, and hemorrhagic assays. Although adult and juvenile venoms showed comparable SDS-PAGE profiles, juveniles lacked some chromatographic peaks compared with adult venom. Adult venom had higher proteolytic (caseinolytic) activity than juvenile venoms (p < 0.05), but there were no significant inter-venom variations in the esterase, PLA2, phosphodiesterase and L-amino acid oxidase (LAAO) activities, although the latter activity was highly variable among the venoms. Juveniles displayed higher coagulant activity on human plasma, with a minimum coagulant dose ∼42% lower than the adult venom (p < 0.05), but there were no age-related differences in thrombin-like activity. Adult venom was more fibrinogenolytic (based on the rate of fibrinogen chain degradation) and hemorrhagic than juvenile venoms (p < 0.05). The effective dose of Bothrops/Lachesis antivenom (produced by the Instituto Butantan) needed to neutralize the coagulant activity was ∼57% greater for juvenile venoms (p < 0.05), whereas antivenom did not attenuate the thrombin-like activity of juvenile and adult venoms. Antivenom significantly reduced the hemorrhagic activity of adult venom (400 μg/kg, i. d.), but not that of juvenile venoms. Overall, these data indicate a compositional and functional ontogenetic shift in L. m. rhombeata venom.

Proteolytic Activity of Silkworm Thorn (Cudrania tricuspidata) Fruit for Enzymatic Hydrolysis of Food Proteins.

This study aimed to isolate the proteolytic fraction from the silkworm thorn fruit (Cudrania tricuspidata) through ethanol precipitation at different ratios, and to determine its proteolytic activity and optimal activity conditions. Furthermore, the hydrolysis characteristics and antioxidant activity of soy protein isolate (SPI) and whey protein concentrate (WPC) hydrolyzates obtained through the enzymatic hydrolysis of freeze-dried silkworm thorn fruit powder (SF) were evaluated. For isolation and partial purification of proteolytic fraction, the water-solubilized fraction of the silkworm thorn fruit was purified through ethanol precipitation at four different ratios of 1:1, 1:2, 1:4, and 1:6 (v/v). The protein recovery rate, caseinolytic activity, protein pattern, and optimal activity (pH, temperature, and inhibitors) of fractional ethanol precipitate obtained from the silkworm thorn fruit (ESF) were evaluated. The proteolytic fraction obtained from silkworm thorn fruit exhibited a major protein band around 65-70 kDa and showed the highest proteolytic activity at a 1:4 ratio of ethanol precipitation (p < 0.05). The optimal activity of the measured enzyme fraction was determined to be at pH 9.0 and 50 °C, and the proteolytic activity of ESF was almost inhibited by phenyl methyl sulphonyl fluoride (PMSF, 2 mM), a serine protease inhibitor. Compared to Alcalase and papain, extensively used as commercial enzymes, the silkworm thorn fruit powder was less effective in hydrolyzing SPI and WPC. Nevertheless, SPI and WPC hydrolyzates mediated with silkworm thorn fruit powder showed even better antioxidant activities than those mediated with Alcalase and papain. Thus, our results show the potential application of silkworm thorn fruit as a novel source of plant protease for producing human-grade protein hydrolyzates.

Proteolytic Activity of Bacillus Strains Isolated from Soil of Rice Agrocenosis

Microorganisms are the most common sources of commercial enzymes due to their physiological and biochemical properties, facile culture conditions, and ease of cell manipulation. Among microbial enzymes, proteases are ubiquitous in nature and have been found in all living forms encompassing the eukaryotes like plants, animals, fungi, and protists as well as the prokaryotic domains of bacteria and archaea. Proteases are the most important for the industry and constitute approximately 60% of the total industrial enzyme market. Among the bacteria, the genus Bacillus has a very prominent place in terms of the commercial production of proteases. Earlier from the water and bottom sediments of the Black Sea, we have isolated a number of producers of proteolytic enzymes from Bacillus species. The aim of this work was to investigate the ability of representatives of a number of soil bacilli species to synthesize enzymes that hydrolyze such protein substrates as elastin, fibrin, fibrinogen, and keratin. Methods. The objects of the study were 8 cultures (KS 1 — KS 8) isolated from the soil of the rice agrocenosis. Cultures were grown under conditions of deep cultivation at 28 °С, with a mixing speed of for the nutrient medium of 230 rpm for 4 days. Methods of determining proteolytic (caseinolytic, elastolytic, fibrinolytic, fibrinogenolytic, and keratinase) activity in the culture liquid supernatant were used. Disulfide reductase activity was measured spectrophotometrically at 412 nm by evaluating the yellow sulfide formed during the reduction of 5,5’-dithiobis-(2-nitrobenzoic acid) (DTNB). Results. The study of the spectrum of proteolytic activities of 8 freshly isolated strains showed that only KS 6 under experimental conditions did not show the ability to hydrolyze any of the studied substrates (casein, elastin, fibrin, fibrinogen, and keratin). Strains KS 1, KS 2, KS 7, and KS 8 showed higher levels of activity compared to other strains studied. The most interesting for further research are: І) strain KS 1, which showed the highest fibrinolytic activity, ІІ) strain KS 2 as the most effective producer with elastase and fibrinogenolytic activity, III) KS 7 and KS 8, which simultaneously showed the highest rates as keratinase (7 U/mL and 9 U/mL) and sulfate reductase (33 μmol/min and 31 μmol/min) activity, respectively. Conclusions. According to the catalytic properties, a number of representatives of Bacillus, isolated from the soil of the rice agrocenosis may be promising for further research as an enzyme producer with proteolytic activity.

Ethanol-salt based two-phase partitioning for concentration of milk clotting proteases from Sweet Indrajao (Wrightia tinctoria R. Br.) fruit

Cheese is the naturally fermented dairy product beloved for its wide variety of textures and other nutritional qualities. Animal rennet, microbial and fermentation produced chymosin are generally considered for commercial level cheese preparation. In order to meet the growing global demand observed in cheese market, milk clotting proteases from diverse alternative sources are under exploration. Sweet Indrajao (Wrightia tinctoria R. Br.) fruit extract is known for its utility in traditional cheese preparation. Organic solvent-salt based aqueous two-phase system (ATPS) using ethanol and salt was employed to partially purify milk clotting proteases from W. tinctoria fruit. The system with ethanol-25.90% (w/w) and dipotassium phosphate-13.60% (w/w) was found favorable with yield of 96.33%, milk clotting index of 77.85, purification factor of 2.42, partition coefficient of 458.80 and selectivity of 345.58. Tricine SDS-PAGE and zymogram revealed presence of two prominent protein bands between 66 and 97.4 kDa with caseinolytic activity. Whole casein and κ- casein hydrolysis pattern was analyzed by tricine SDS-PAGE. The optimized system was scaled up to 100 g and its performance was found comparable to its 10 g counterpart. Characteristics of the cheese prepared using partitioned enzyme was comparable to that of the positive control used (Enzeco®).

Substrate Specificity of Bacillus megaterium UСM B-5710 Keratinase

The specifics of the processing of livestock and poultry products is that in the process of obtaining the main marketable products, about half the feedstock at various stages of the technological process turns into waste that pollutes the environment. These by-products contain large amounts of the hard-to-digest keratin protein. The use of specific enzymes capable of degrading this protein helps not only to reduce the negative anthropogenic impact on nature but also to obtain valuable hydrolysates that can be used as a fertilizer for plants or a feed additive. The aim of this work was to study the ability of Bacillus megaterium UCM B-5710 to split various keratin-containing substrates: black and white chicken feathers, white turkey feathers, parrot feathers of various colors, sheep wool, pig bristles, and baby hair and nails. Methods. The culture was grown under conditions of submerged cultivation at 40 °C, with a nutrient medium stirring rate of 201 rpm for 6 days. For growth, a basic nutrient medium containing 0.5% defatted chicken feathers or other keratin-containing substrates as sole sources of carbon and nitrogen were used. Keratinase activity was assessed by UV absorption at 280 nm of hydrolysis products of keratin-containing raw materials. Protein was determined by the Lowry method, caseinolytic (total proteolytic) activity was determined by the Anson method modified by Petrova, and amino acid content was determined by the ninhydrin method. The degree of hydrolysis of the substrates was evaluated by the ratio of the initial and final weight of the substrate. Results. It was shown that the synthesis of keratinase by the culture of B. megaterium UCM B-5710 begins from the 6th hour of cultivation. The level of protein and proteolytic activity and the content of amino acids increased throughout the entire period of culture growth. The supernatant of the culture liquid of B. megaterium UCM B-5710 was most effective in splitting white chicken’s and turkey’s feathers, a little slower — feathers of black chicken and blue parrots, as well as wool of white sheep. According to the degree of splitting, the substrates used can be arranged in the following order: white turkey feathers &gt; white chicken feathers &gt; black chicken feathers &gt; blue parrot feathers &gt; white sheep wool &gt; baby nails &gt; pig bristle &gt; baby hair. The study of the effect of feather color on the resistance to decomposition showed that black, blue, and red feathers are more resistant, which coincides with the literature data. Conclusions. B. megaterium UCM B-5710 produces keratinase capable of splitting both α- and β-keratins, however, with different efficiencies and rates.

Efficacy of a Mexican folk remedy containing cuachalalate (Amphipterygium adstringens (Schltdl.) Schiede ex Standl) for the treatment of burn wounds infected with Pseudomonas aeruginosa

Ethnopharmacological relevanceCuachalalate (Amphipterygium adstringens) stem bark has been used to heal wounds and counteract microbial infections since pre-Hispanic times. However, its effect in treating infected burns remains unclear. Study objectivesTo determine the antipathogenic capacity of a folk remedy (FR) containing cuachalalate stem bark to treat lesions caused by thermal damage and bacterial infection. Materials and methodsThe antipathogenic capacity of the hexanic extract (HE) and FR was evaluated in a burned mouse model infected with Pseudomonas aeruginosa. Second to third-degree burns were induced with 95 °C water in CD1 mice in similar ratios of males to females. The mice were randomly grouped into non-inoculated (Group 1) and P. aeruginosa inoculated. The latter were divided into untreated infection (Group 2) and infection topically treated with HE (Group 3), silver sulfadiazine (Group 4), and tween 80 (Group 5). In the case of FR, the lesions were washed with an aqueous extract (AE) and applied powdered stem bark (Group 6). Animal survival, establishment of the bacteria in the lesions, and systemic dispersion were determined. In addition, histopathological analysis was performed. The chemical composition of the AE was analyzed through molecular networking analysis, and the antivirulence capacity was determined through the inhibition of pyocyanin production and caseinolytic activity. ResultsOnly the FR showed antipathogenic activity and increased animal survival by 50% by reducing the systemic dispersion of P. aeruginosa. In addition, it stimulated the formation of granulation tissue and the generation of new blood vessels. The AE did not show bactericidal activity but reduced bacterial virulence, and glycosylated flavonoids and catechins were identified as its main constituents. ConclusionsThe results of this study contribute to validating the effectiveness of a popular remedy containing cuachalalate stem bark for treating burns infected with P. aeruginosa.

Evaluation of by-products from agricultural, livestock and fishing industries as nutrient source for the production of proteolytic enzymes

This study presents an approach that utilizes low-value agro-industrial by-products as culture media for producing high-value proteolytic enzymes. The objective was to assess the impact of six agro-industrial by-products as culture media on the production of proteolytic enzymes. Bacillus subtilis strains, confirmed through comprehensive biochemical, morphological, and molecular analyses, were isolated and identified. Enzymatic activity was evaluated using azocasein and casein substrates, and the molecular sizes of the purified extract components were determined. The results demonstrated that the isolated bacteria exhibited higher metabolic and enzymatic activity when cultured in media containing 1 % soybean oil cake or feather meal. Furthermore, higher concentrations of the culture media were found to hinder the production of protease. Optimal protease synthesis on soybean oil cake and feather meal media was achieved after 4 days, using both the azocasein and casein methods. Semi-purification of the enzymatic extract obtained from Bacillus subtilis in feather meal and soybean oil cake resulted in a significant increase in azocaseinolytic and caseinolytic activities. Gel electrophoresis analysis revealed multiple bands in the fractions with the highest enzymatic activity in soybean oil cake, indicating the presence of various enzymes with varying molecular sizes. These findings highlight the potential of utilizing low-value agro-industrial by-products as efficient culture media for the sustainable and economically viable production of proteolytic enzymes with promising applications in various industries.

Optimization of caseinolytic and coagulating activities of Solanum tuberosum rennets for cheese making.

In recent years, the rising global demand for cheese, the high cost and limited supply of calf rennet, and consumer choices have increased research into new alternatives to animal or recombinant chymosins for cheese making. Plant proteases with caseinolytic activity (CA) and milk-clotting activity (MCA) have been proposed as alternatives for milk clotting to obtain artisanal cheeses with new organoleptic properties. They have been named vegetable rennets (vrennets). The aim of this study was to evaluate the performance of two Solanum tuberosum aspartic proteases (StAP1 and StAP3) as vrennets for cheese making and to obtain a statistical model that could predict and optimize their enzymatic activity. To optimize the CA and MCA activities, a response surface methodology was used. Maximum values of CA and MCA for both enzymes were found at pH 5.0 and 30-35 °C. Analysis of the degradation of casein subunits showed that it is possible to tune the specificity of both enzymes by changing the pH. At pH 6.5, the αS - and β- subunit degradation is reduced while conserving a significant MCA. The statistical models obtained in this work showed that StAP1 and StAP3 exert CA and MCA under pH and temperature conditions compatible with those used for cheese making. The casein subunit degradation percentages obtained also allowed us to select the best conditions for the degradation of the κ-casein subunit by StAPs. These results suggest that StAP1 and StAP3 are good candidates as vrennets for artisan cheese making. © 2023 Society of Chemical Industry.

New Coagulant Proteases for Cheesemaking from Leaves and Latex of the Spontaneous Plant Pergularia tomentosa: Biochemical Characterization of Coagulants and Sensorial Evaluation of Cheese

The purpose of this study was to evaluate the caseinolytic and milk-clotting activities of aqueous crude extracts from leaves and latex of the Pergularia tomentosa, to determine their suitability as a rennet substitute. These extracts were subjected to a series of biochemical tests before being used in the production of cheese. The results showed that the enzymatic latex extract had a higher coagulant activity than the leaf extract. However, under different clotting conditions (pH, temperature, and CaCl2 concentration), both coagulants behaved similarly in the coagulation of Berridge substrate. The SDS-PAGE and zymographic analysis revealed identical protein bands with a single active zone in both extracts, corresponding to a molecular weight of 26.98 kDa and 26.03 kDa in the extract of leaf and latex, respectively. Both extracts were stable to different effectors but strongly inhibited by iodoacetamide and Hg, suggesting it to be a cysteine protease. Both extracts were able to hydrolyze casein and generate peptides of 14 kDa, with excessive hydrolysis of the other casein fractions. The physicochemical parameters of cheese made from latex and leaf extract evolved similarly to control cheese. According to the sensory evaluation, cheese made with latex had a mildly bitter flavor but showed a high acceptance rate (&gt;80%).

Activation mechanism and activity of globupain, a thermostable C11 protease from the Arctic Mid-Ocean Ridge hydrothermal system.

Deep-sea hydrothermal vents offer unique habitats for heat tolerant enzymes with potential new enzymatic properties. Here, we present the novel C11 protease globupain, which was prospected from a metagenome-assembled genome of uncultivated Archaeoglobales sampled from the Soria Moria hydrothermal vent system located on the Arctic Mid-Ocean Ridge. Sequence comparisons against the MEROPS-MPRO database showed that globupain has the highest sequence identity to C11-like proteases present in human gut and intestinal bacteria. Successful recombinant expression in Escherichia coli of the wild-type zymogen and 13 mutant substitution variants allowed assessment of residues involved in maturation and activity of the enzyme. For activation, globupain required the addition of DTT and Ca2+. When activated, the 52kDa proenzyme was processed at K137 and K144 into a 12kDa light- and 32kDa heavy chain heterodimer. A structurally conserved H132/C185 catalytic dyad was responsible for the proteolytic activity, and the enzyme demonstrated the ability to activate in-trans. Globupain exhibited caseinolytic activity and showed a strong preference for arginine in the P1 position, with Boc-QAR-aminomethylcoumarin (AMC) as the best substrate out of a total of 17 fluorogenic AMC substrates tested. Globupain was thermostable (Tm activated enzyme = 94.51°C ± 0.09°C) with optimal activity at 75°C and pH 7.1. Characterization of globupain has expanded our knowledge of the catalytic properties and activation mechanisms of temperature tolerant marine C11 proteases. The unique combination of features such as elevated thermostability, activity at relatively low pH values, and ability to operate under high reducing conditions makes globupain a potential intriguing candidate for use in diverse industrial and biotechnology sectors.

Clotting and Proteolytic Activity of Freeze-Dried Crude Extracts Obtained from Wild Thistles Cynara humilis L. and Onopordum platylepis Murb.

The rising interest in finding alternatives to animal rennet in cheese production has led to studying the technological feasibility of using and exploiting new species of herbaceous plants. In this research work, and for the first time, freeze-dried extracts from Cynara humilis L. (CH) and Onopordum platylepis Murb. (OP) were studied for mineral and protein content, and their clotting and proteolytic activity were compared to those of Cynara cardunculus L. (CC). The effect of extract concentration (5-40 mg extract/mL), temperature (20-85 °C), pH (5-8), and CaCl2 concentration (5-70 mM) on the milk clotting activity (MCA) of CC, CH and OP extracts was evaluated. The MCA values were significantly higher in CC at the same extract concentration. The extract that showed the most significant increase in clotting activity due to increased temperature was OP, with maximum activity at 70 °C. The pH value for maximum milk clotting was 5.0 for both CC and CH, whereas, in the case of OP, the pH value was 5.5. CaCl2 enhanced the clotting capacity of the extracts, particularly for OP and CH. Furthermore, proteolytic activity (PA) and the hydrolysis rate increased with increasing time and enzyme concentration, with CC being the extract that achieved the highest caseinolytic activity.