High Proteolytic Activity Research Articles

Ex Situ Conservation, DNA Barcoding and Enzymatic Potential Evaluation of Macrofungi (Basidiomycota, Ascomycota) from Vietnam.

The diversity and resource potential of macroscopic fungi in tropical regions remain understudied. Vietnam, being in a biodiversity hotspot, has a large number of new fungal species that are of interest for biotechnology and medicine. The presence of a large number of protected areas in Vietnam creates favorable opportunities for the study and ex situ conservation of tropical biodiversity. From 2012 to 2023, 785 strains of macrofungi from National Parks of Vietnam were preserved in the LE-BIN collection, 327 of which were barcoded with the sequences deposited in the NCBI GenBank. A taxonomic analysis demonstrated that many of the preserved isolates are potentially new or poorly studied species, representing a useful resource for taxonomical studies and a search for new medicinal mushrooms. More than 180 strains were studied for the first time for growth rate and enzymatic activities. Of these, 53 strains showed high growth rate, 43-high cellulolytic activity, 73-high oxidative enzymes activity, and 27 showed high proteolytic activity, making them promising candidates for biotechnological and medical applications and opening new opportunities for sustainable biomass management, discovery of new enzymes and bioactive substances, development of new drugs and efficient plant waste treatment technologies. The results confirm the importance of the ex situ conservation of fungal diversity in tropical regions as a valuable source for scientific and commercial applications and suggest certain new active strains for biotechnological study.

Selection and transcriptomic analysis of coagulase-negative Staphylococcus with high proteolytic activity isolated from Chinese Dong fermented pork (Nanx Wudl)

Selection and transcriptomic analysis of coagulase-negative <em>Staphylococcus</em> with high proteolytic activity isolated from Chinese Dong fermented pork (Nanx Wudl)

Unraveling the Potential of Yarrowia lipolytica to Utilize Waste Motor Oil as a Carbon Source.

This study evaluated the potential of Y. lipolytica (CBS 2075 and DSM 8218) to grow in waste motor oil (WMO) and produce valuable compounds, laying the foundation for a sustainable approach to WMO management. Firstly, yeast strains were screened for their growth on WMO (2-10 g·L-1) in microplate cultures. Despite limited growth, the CBS 2075 strain exhibited comparable growth to control conditions (without WMO), while DSM 8218 growth increased 2- and 3-fold at 5 g·L-1 and 10 g·L-1 WMO, respectively. The batch cultures in the bioreactor confirmed the best performance of DSM 8218. A two-stage fed-batch strategy-growth phase in aliphatic hydrocarbons, followed by the addition of WMO (one pulse of 5 g·L-1 or five pulses of 1 g·L-1 WMO), significantly increased biomass production and WMO assimilation by both strains. In experiments with five pulses, CBS 2075 and DSM 8218 strains reached high proteolytic activities (593-628 U·L-1) and accumulated high quantities of intracellular lipids (1.3-1.7 g·L-1). Yeast lipids, mainly composed of oleic and linoleic acids with an unsaturated/saturated fraction > 59%, meet the EU biodiesel standard EN 14214, making them suitable for biodiesel production.

Feta cheese: A pool of Non-Starter Lactic Acid Bacteria (NSLAB) with anti-hypertensive potential

Feta cheese: A pool of Non-Starter Lactic Acid Bacteria (NSLAB) with anti-hypertensive potential

Selection of Proteolytic Lactic Acid Bacteria with Probiotic Properties for Fish Protein Hydrolyzate Production

This study aimed to select a proteolytic LAB with probiotic properties that can be applied to manufacture protein hydrolysate from fish heads. Tests on 20 isolates of LAB showed that nine isolates were proteolytic and non-pathogenic. A total of 5 isolates could grow well at 0.5% bile salt stress, and 3 of them could grow at pH 3. These three isolates had antagonistic ability against Salmonella bacteria, and one isolate was sensitive to the antibiotic tested. Molecular identification of the selected LAB isolates showed a 100% sequence similarity with Pediococcus pentosaceus with accession number MT515895.1. The LAB isolate has high proteolytic activity since it can increase the soluble fraction of fish meal powder from 32.10% to 88.38% in 48 hr. Production of protein hydrolysate using tuna waste was carried out for 30 days. Tuna waste protein hydrolysate had a medium antioxidant activity of 25.57 ± 0.93%. The hydrolyzed protein comprised 17 amino acids, including nine non-essential and eight essential amino acids, and is dominated by glutamic acid. Selected LAB isolate is potentially used in protein hydrolysate production, especially for flavor enhancers. Keywords: antagonistic, amino acid, Pediococcus pentosaceus

Production of anti-rM14 and anti-rM42 antibodies and their application in the stidy of expression of metalloproteases M14 and M42 of keratinolytic strain of Bacillus paralicheniformis

In the present study, two metalloproteases M14 and M42 from a Kazakh strain of Bacillus paralicheniformis T7 with high proteolytic activity were successfully cloned, expressed and purified. Protease genes were amplified by polymerase chain reaction (PCR) using specific primers selected on the basis of full genome sequencing data of B. paralicheniformis strain N7 (GenBank accession #CP124861). The amplified fragments were cloned in the expression vector pET-28c(+). Recombinant analogs of the metalloproteases M14 and M42 were obtained by plasmid expression in Escherichia coli cells of the strain ArcticExpressRP(DE3). Using metal affinity chromatography, rM14 and rM42 proteins were purified and polyclonal antibodies were produced by immunization of rabbits. Using anti-rM14 and anti-rM42 antibodies, the expression level of native metalloproteases M14 and M42 in cell lysate and culture fluid of B. paralicheniformis T7 strain was examined after culturing the strain on keratin-containing media: chicken feather, horn, hoof, hide and wool of cattle. Substrate-dependent expression of metalloprotease genes of B. paralicheniformis strain T7 was established. The obtained results indicate the prospective use B. paralicheniformis strain T7 as a producer of metalloproteases M14 and M42.

New Bacillus paralicheniformis strain with high proteolytic and keratinolytic activity.

Bacillus paralicheniformis T7, which exhibits high proteolytic and keratinolytic activities, was isolated from soil in Kazakhstan. Its secreted proteases were thermostable and alkaline, demonstrating maximum activity at 70°C and pH 9.0. The proteases and keratinases of this strain were sensitive to Ni2+, Co2+, Mn2+, and Cd2+, with Cu2+, Co2+ and Cd2+ negatively affecting keratinolytic activity, and Fe3+ ions have a strong inhibitory effect on proteolytic and keratinolytic activity. Seven proteases were identified in the enzymatic extract of B. paralicheniformis T7: four from the serine peptidase family and three from the metallopeptidase family. The proteases hydrolyzed 1mg of casein, hemoglobin, gelatin, ovalbumin, bovine serum albumin, or keratin within 15s to 30min. The high keratinolytic activity of this strain was confirmed through the degradation of chicken feathers, horns, hooves, wool, and cattle hide. Chicken feathers were hydrolyzed in 4 days, and the degrees of hydrolysis for cattle hide, wool, hoof, and horn after 7 days of cultivation were 97.2, 34.5, 29.6, and 3.6%, respectively. During submerged fermentation with feather medium in a laboratory bioreactor, the strain secreted enzymes with 249.20 ± 7.88 U/mL protease activity after 24h. Thus, B. paralicheniformis T7 can be used to produce proteolytic and keratinolytic enzymes for application in processing proteinaceous raw materials and keratinous animal waste.

Fecal Proteolytic Bacteria and Staphylococcal Superantigens Are Associated With Abdominal Pain Severity in Irritable Bowel Syndrome.

Changes in the composition of the gut microbiota have been associated with the development of irritable bowel syndrome (IBS). However, to what extent specific bacterial species relate to clinical symptoms remains poorly characterized. We investigated the clinical relevance of bacterial species linked with increased proteolytic activity, histamine production, and superantigen (SAg) production in patients with IBS. Fecal (n = 309) and nasal (n = 214) samples were collected from patients with IBS and healthy volunteers (HV). Clinical symptoms and gut transit time were evaluated. Bacterial abundance in feces and nasal swabs as well as fecal trypsin-like activity were assessed. The percentage of fecal samples containing Staphylococcus aureus was significantly higher in IBS compared with HV. Forty-nine percent of S. aureus -positive fecal samples from patients with IBS were also positive for SAgs, compared with 12% of HV. Patients with IBS and positive fecal SAg-producing S. aureus reported higher pain scores than those without S. aureus . Moreover, increased fecal proteolytic activity was associated with abdominal pain. Fecal abundance of Paraprevotella clara and Alistipes putredinis was significantly decreased in IBS, particularly in samples with higher proteolytic activity. Patients with lower Alistipes putredinis or Faecalibacterium prausnitzii abundance reported more severe abdominal pain. In keeping with our preclinical findings, we show that increased presence of SAg-producing S. aureus in fecal samples of patients with IBS is associated with increased levels of abdominal pain. We also show that increased fecal proteolytic activity is associated with increased abdominal pain in patients with IBS.

Quince Powder Increases Antioxidant Activity and Probiotic Survival in Yoghurt.

In recent years, there has been a growing interest in incorporating fruit-based additives into yogurt formulations as a means to improve the functionality of the product. This study aims to produce a functional product by incorporating quince, which is rich in fibre, vitamins, minerals and antioxidant activity, into a yoghurt formulation. The influence of the addition of quince powder (0 (control), 0.5, 1.0 and 1.5 %) on the antioxidant and proteolytic activities and culture viability of probiotic yoghurt was investigated for 28 days. The viable counts of yoghurt bacteria and Bifidobacterium lactis BB-12® were above 8 log CFU/g. Higher viability of all bacteria was obtained in yoghurt fortified with 1.5 % quince powder than those of other samples after 14 days. Probiotic yoghurt with added 1.5 % quince powder had the highest proteolytic activity during the last two weeks of storage, while the highest total phenolic content and (2,2-diphenyl-1-picrylhydrazyl) radical (DPPH˙) scavenging activity were obtained for the same sample throughout the storage period. Quince powder supports the health of the digestive system thanks to its high fibre content, while it is also rich in vitamins, minerals and antioxidant activity. These properties emphasise the importance of using quince powder in yoghurt production. This innovation has the potential to provide consumers with a tasty alternative, while at the same time increasing the intake of health-promoting ingredients. Furthermore, such products offer higher nutritional value than conventional yoghurt, offering consumers with a healthier option. Therefore, the production of yoghurt with quince powder can be considered as an important innovation in the field of nutrition and a practice that contributes to increasing health awareness.

Enzymatic hydrolysis of chicken viscera and bones: Rest raw material characterization and evaluation of industrially relevant process parameters on product yields

Enzymatic hydrolysis of chicken viscera and bones: Rest raw material characterization and evaluation of industrially relevant process parameters on product yields

Ферменты биомассы мицелия грибов Cordyceps militaris и Lentinula edodes в технологии хлеба

Cordyceps militaris and Lentinula edodes are known for their high extracellular proteolytic, amylolytic, and laccase activity, which is important for bakery production. This article describes the effect of enzymes obtained from mycelial biomass of C. militaris and L. edodes on such properties of flour mixes as amylolytic and proteolytic enzymic activity during baking, technological costs, and bread quality. The research featured strains of C. militaris SRG4 and L. edodes 3790 fungi; mycelial biomass powder of these fungi on a sterile grain substrate (rice, wheat); experimental flour mixes of wheat bread and first-grade baking flour with mycelial biomass powder; bread made from the experimental flour mixes. The experimental part included standard methods used in the bakery industry. The mycelial biomass of C. militaris and L. edodes fungi proved to be a promising baking additive because it possessed hydrolytic enzymes and was rich in protein substances (32.2 ± 1.5 and 26.4 ± 2.0%, respectively), specific mushroom polysaccharides (36.7 ± 0.8 and 52.2 ± 1.2%, respectively), and carotenoids (1600 ± 40 mcg/g of C. militaris biomass). The active amylases and proteinases in the mycelial biomass powder improved the sugar-forming ability and reduced the falling number. In addition, they raised the amount of washed gluten with a slight decrease in elasticity, as well as provided an acceptable structure and viscosity of the dough at 1–4% of mycelial biomass powder. This dose resulted in an optimal bread formulation of standard quality. A bigger amount caused the crumb to darken and increased its humidity while reducing the specific volume. The bread samples with C. militaris were too acid. Mycelial biomass of C. militaris and L. edodes proved to be a good source of enzymes to be used with grain substrates in bakery production. Further research is needed to define the optimal dose and processing modes.

Advantages and disadvantages of autochthonous enterococci strains for their potential use in cheese ripening: a preliminary study

SummaryThe enzymatic activity exhibited by native enterococci could, in turn, result in a reduction in the cheese ripening time. However, they may also carry virulence factors or resistance to antibiotics that prevent their use in food. A total of 69 enterococci isolates were obtained from a Spanish traditional raw goat's milk cheese and identified by Maldi‐Tof/MS. Different enzymatic activities of technological interest were evaluated and the safety of those with greater technological suitability was studied. The strains were identified as E. malodoratus, E. italicus, E. gilvus, E. faecium, E. durans, E. casseliflavus and E. faecalis. Some strains had very high acidifying and proteolytic activities. Most strains had medium or low amino and carboxypeptidase activities and high dipeptidase activities, while esterase activities were medium. A total of 10 strains were selected based on their enzymatic activities. Of these, five showed β‐haemolysin activity, eight showed gelatinase activity and eight produced tyramine. These activities represent virulence factors that could potentially affect food safety. Finally, all selected strains were susceptible to the antibiotics tested.

Evaluation of the Functional and Sensory Properties of Probiotic Whey Cheese with Herbs in Vacuum or Modified Atmosphere Packaging.

Some herbs provide functional properties to foods, especially their antibacterial and antioxidant properties. On the other hand, modified atmosphere packaging is being considered as an alternative to vacuum packaging to preserve the functional and sensory properties of foods. Since the shelf life of whey cheese is quite short, different packaging methods such as modified atmosphere packaging are favoured. Besides, the addition of herbs both gives flavour to the cheese and improves its functional properties. In the present study, oregano (Origanum onites) or rosemary (Rosmarinus officinalis) was added to probiotic whey cheese (lor) containing Lactobacillus acidophilus La-5 and Bifidobacterium lactis Bb-12 under modified atmosphere packaging (MAP) (80 % CO2 and 20 % N2) or vacuum packaging. The physicochemical, microbiological and sensory properties as well as antioxidant and proteolytic activities of the cheese samples were determined. The addition of herbs did not negatively affect the viable counts of B. lactis and L. acidophilus, and the cheese samples contained at least 8 log CFU/g of both probiotic bacteria for 35 days. MAP improved the viability of B. lactis and L. acidophilus in cheese with rosemary during the first few weeks of storage compared to vacuum packaging. The addition of herbs significantly increased the total phenolic content and antioxidant activity under both MAP and vacuum. MAP improved the antioxidant activity of lor cheese with added herbs on days 14 and 28 more than vacuum packaging. Lor cheese with rosemary under MAP conditions showed the highest DPPH˙ (2,2,-diphenyl-1-picrylhydrazyl) scavenging activity and also the highest proteolytic activity throughout storage. The sample with rosemary under MAP had the highest taste and aroma scores throughout the entire storage period. Fortification with herb and MAP offers advantages in the production of whey cheese. The use of rosemary and modified atmosphere packaging makes it possible to achieve high viability of probiotic bacteria, total phenolic content, antioxidant activity and sensory acceptance in lor cheese. This is the first study in which both different herbs and different packaging methods were applied to probiotic whey cheese (lor). The study shows that the functional properties of whey cheese can be improved by using different herbs under different packaging conditions. Among the analysed properties of the product, the improvement of the viability of probiotic bacteria is particularly valuable for human health. Thus, it contributes to the science of functional food and enables the use of these parameters in some other foods.

Peptidomics-based identification of antihypertensive and antidiabetic peptides from sheep milk fermented using Limosilactobacillus fermentum KGL4 MTCC 25515 with anti-inflammatory activity: in silico, in vitro, and molecular docking studies.

This study investigated the synthesis of bioactive peptides from sheep milk through fermentation with Limosilactobacillus fermentum KGL4 MTCC 25515 strain and assessed lipase inhibition, ACE inhibition, α-glucosidase inhibition, and α-amylase inhibition activities during the fermentation process. The study observed the highest activities, reaching 74.82%, 70.02%, 72.19%, and 67.08% (lipase inhibition, ACE inhibition, α-glucosidase inhibition, and α-amylase inhibition) after 48h at 37°C, respectively. Growth optimization experiments revealed that a 2.5% inoculation rate after 48h of fermentation time resulted in the highest proteolytic activity at 9.88mg/mL. Additionally, fractions with less than 3kDa of molecular weight exhibited superior ACE-inhibition and anti-diabetic activities compared to other fractions. Fermentation of sheep milk with KGL4 led to a significant reduction in the excessive production of NO, TNF-α, IL-6, and IL-1β produced in RAW 267.4 cells upon treatment with LPS. Peptides were purified utilizing SDS-PAGE and electrophoresis on 2D gels, identifying a maximum number of proteins bands ranging 10-70kDa. Peptide sequences were cross-referenced with AHTPDB and BIOPEP databases, confirming potential antihypertensive and antidiabetic properties. Notably, the peptide (GPFPILV) exhibited the highest HPEPDOCK score against both α-amylase and ACE.

Exploring New Fruit- and Vegetable-Derived Rennet for Cheese Making

Cheese production is an ancient practice to preserve a perishable food, such as milk, for a long time. The first step of cheese processing involves the addition of rennet, which contains the enzymes necessary for the hydrolysis and coagulation of the caseins present in milk. Typically, animal-derived rennet, such as calf rennet containing chymosin, are used as source of enzymes for cheese processing. Alternatively, microbial chymosin or recombinant chymosin is used. However, recently, plant-derived rennet such as the ones derived from thistle and bitter orange flowers and from artichoke (Cynara cardunculus var. scolymus) have also been demonstrated to be valid sources of enzymes for cheese processing. Therefore, herein, different plant and fruit extracts were tested and compared for their ability to coagulate milk caseins. In particular, beyond artichoke and cardoon (Cynara cardunculus) extracts, those from pineapple (Ananas comosus (L.) Merr.), papaya (Carica papaya L.), common fig (Ficus carica L.) milky sap, and oyster mushroom (Pleurotus ostreatus (Jacq. ex Fr.) P. Kumm.) were investigated for their proteolytic, esterase, and milk-clotting activities. The extracts were then exploited as vegetable and fruit rennet for the experimental production of cheeses, which were examined, after 30 days of maturation, for their moisture, fat, protein, and free fatty acid (FFA) content. Interestingly, the artichoke, cardoon, and thistle mushroom extracts showed high proteolytic activity compared to calf rennet, while the level of esterase activity appeared to be similar for all the extracts. The papaya extract showed the lowest proteolytic and esterase activity. Although the pH, moisture, fat, and protein contents were very similar to those of cheese made with calf rennet, the medium- and long-chain FFAs broadly differed among produced cheeses, with variations in the lipid quality indices.

Study and characterization of a product based on a vegetable extract of quinoa fermented with water kefir grains.

This work aimed to study and characterize a product based on vegetable extract of quinoa (WVEQ) fermented with water kefir grains. The effect of sucrose concentration (SC), inulin concentration (IC), and xanthan gum (XG) concentration were evaluated using a central composite design (CCD) 23. They were subsequently characterized regarding cellular growth of the grains, beverage yield, pH, soluble solids, carbon dioxide (CO2) production, lactic acid, and ethanol production. Therefore, for the final stage, two formulations (F1 and F8) of the CCD were chosen to be characterized in terms of proximate composition, microbiological composition of the kefir culture, analysis of organic compounds, sensory analysis, and enzymatic and microbiological characterization before and after simulation of in vitro gastrointestinal digestion. In the two chosen products, one can see that fermentation optimized the bioavailability of proteins due to the high proteolytic activity of the microorganisms in kefir and the increase in lipid content. In identifying microorganisms, there was a prevalence of Saccharomyces sp. yeasts. In the sensory analysis, the F8 formulation showed better results than the F1 formulation. In vitro, gastrointestinal digestion showed reduced lactic acid bacteria and yeast and increased acetic acid bacteria in the liquid phase for both formulations. In the enzymatic profile, there was a reduction in all enzymes analyzed for both formulations, except for amylase in F1, which went from 14.05 U/mL to 39.41 U/mL. Therefore, it is concluded that using WVEQ as a substrate for the product appears to be a viable alternative with nutritional and technological advantages for serving a specific market niche.

A42 A HIGH SALT DIET INCREASES ELASTOLYTIC ACTIVITY AND WORSENS COLITIS IN GNOTOBIOTIC MICE

Abstract Background Recent evidence has linked ultra-processed foods, which are high in salt, to increased risk of inflammatory bowel disease (IBD). A high salt diet (HSD) was also shown to be colitogenic in specific pathogen-free mice, in part, through modulation of the microbiota. We recently described high microbial proteolytic activity (PA) in feces from IBD patients, that when transferred to germ-free mice, increased acute colitis severity. However, the drivers of high microbial PA are unknown. Aims To determine whether HSD increases proteolytic activity, thereby exacerbating colitis. Methods Adult germ-free (GF) C57BL/6 mice were colonized with feces from a patient with UC in flare (n=13). Mice were fed either a control diet (CD; 7004, Teklad) or a HSD (7004 supplemented with 4% NaCl) plus 1% NaCl in drinking water. Three weeks following colonization, chronic colitis was induced in half of the mice by three cycles (five days each; 2.0%, 1.5% and 1.5%, respectively) of DSS in drinking water with a five-day wash-out period between cycles. Fecal PA and predicted microbial protease profiles were measured before colitis induction. Weight loss and disease activity (e.g., occult blood in feces and stool consistency) was evaluated for the duration of colitis and microscopic colitis was evaluated at endpoint. Results In mice colonized with UC microbiota, a HSD increased elastolytic activity (p=.03 versus CD) and induced a unique predicted protease and peptidase profile. After colitis induction, mice consuming a HSD lost more weight than mice consuming the CD (p=.0001) and had higher disease activity (p=.0004). Additionally, HSD induced more severe microscopic colitis scores compared with the CD (p=.0001). Conclusions These results raise the hypothesis that a HSD drives microbial proteolytic activity of IBD microbiota. However, whether this shift is causally associated with the worsening of colitis remains unclear. Mechanistic insight underlying this HSD-microbial proteolytic function could lead to specific dietary modifications or anti-proteolytic therapies for IBD in patients with proteolytic-driven inflammation. Funding Agencies CCC, CIHR

In Vitro Digestibility Assessment of Whey from Goat and Camel Milk Fermented with Lactobacillus helveticus for Use as a Base in Formulating Follow-On Formula.

Follow-on formulas are necessary for newborns that are unable to breastfeed. Thus, the development of formulas more tailored to infants' needs is highly important. Recently, using camel milk, goat milk, and sweet milk whey in the formulation of follow-on formulas has gained researchers' attention. Moreover, developing postbiotic systems to create formulas that mimic human milk, are easy to digest, improve compatibility with an infant's gut, and boost immunity is crucial. Thus, this study aimed to create and assess different formulations using fermented whey from camel and goat milks. The fermentation process involved the use of Lactobacillus helveticus as a probiotic and proteolytic lactic acid bacterium strain. The study monitored the proteolytic activity and antioxidant properties of sweet whey produced from cow, camel, and goat milks during the fermentation process with L. helveticus. Also, three different milk fat blends were recombined using edible vegetable oils (coconut oil, rice bran oil, and canola oil) and then they were used to formulate follow-on formulas with a similar fat composition to human milk. Finally, the prepared formulas were tested for their in vitro digestibility and antioxidant activity before and after digestion. The L. helveticus strain had high proteolytic activity towards whey proteins from all the types of milk used in the study. A fermentation time of 6 h produced a higher proteolytic degree and antioxidant activity than 2 and 4 h of fermentation. No significant differences were observed for proteolytic degree and antioxidant activity between 6 and 12 h of fermentation for the cow, camel, and goat whey samples. Regarding the fat blends, animal milk fat, rice bran oil, and canola oil in a fat combination were essential to provide the required amount of unsaturated fatty acids in the follow-on formulas, especially the linoleic acid-α-linolenic acid (LA:ALA) ratio. Adding coconut oil in small amounts to the follow-on formulas provided the required amounts of saturated fatty acids, especially lauric and meristic acids. The follow-on formula based on cow or goat milk whey fermented with L. helveticus released more free amino acids (mmol tyrosine equivalent mL-1) with high levels of antioxidants compared to unfermented ones. The release of free amino acids in the follow-on formula based on camel milk whey was not affected by fermentation. Our results recommend using L. helveticus in the fermentation of follow-on formulas based on camel and goat whey instead of formulas based on cow milk proteins.

Occurrence and risk‐related features of Bacillus cereus in fluid milk

This work assessed the prevalence and risk‐related phenotypes of Bacillus cereus in milk products. Bacillus was the most dominant genus of 113 collected strains from 41 milk samples, and B. cereus (19.27%) was the most abundant species showing a high genetic diversity with seven random amplified polymorphic DNA patterns. Most B. cereus isolates were strong biofilm formers with good motility, extracellular polymeric substance‐producing ability, high proteolytic and lipolytic activities. Antibiotic resistance analysis suggested the majority B. cereus strains were resistant to oxacillin (90.48%), tetracycline (95.24%), and penicillin G sodium (47.62%). Results revealed the genotypic diversity of B. cereus, and their potential risk in dairy industry.

Evaluation of biotechnological potential of new strains of lactic acid bacteria with cryoresistant properties

Intensive introduction in the baking industry of technologies using freezing of semi-finished and finished products requires new approaches in the development of starter cultures for baking, which is primarily due to a decrease in cell viability and changes in their functional and technological properties under low-temperature exposure. In this regard, research aimed at the search, selection, study of new lactic acid bacteria strains with cryoresistant properties is timely and relevant. In the present work, a comparative assessment of the biotechnological potential of previously isolated strains of lactic acid bacteria with high resistance to low-temperature treatment was carried out. It was found that strains L. bavaricus 6, L. casei 32 and L. plantarum 24 show high tolerance to a number of antibiotics, are characterized by a wide spectrum of antibacterial action, inhibit the growth of mycelial fungi and yeasts, have high proteolytic activity, and are also characterized as salt-, bile-, acid- and phenolu-resistant strains. This serves as a basis for predicting their probiotic properties and makes it promising to use them for the development of new food products with functional properties. The conducted studies allow us to recommend these strains for inclusion in the composition of starter starters for fermented foods products using cryogenic technologies, including bakery products based on frozen semi-finished products. These strains can be recommended for the development of biologically active additives for food, pharmaceutical, cosmetic industries and veterinary.