Brazilian Journal of Microbiology最新文献

{"title":"Global expression profile of enterohemorrhagic Escherichia coli O157:H7 in phagosome of murine macrophages.","authors":"Nahuel Agustín Riviere, Lin Jiang, Xiuju Wu, Pablo Farace, Lu Guo, Libia Yael Smith, Wanderson Marques Da Silva, Ángel Adrián Cataldi, Ke Xing, Jinlong Bei, Mariano Larzábal","doi":"10.1007/s42770-026-02048-x","DOIUrl":"10.1007/s42770-026-02048-x","url":null,"abstract":"<p><p>Enterohemorrhagic Escherichia coli (EHEC) O157:H7 causes foodborne outbreaks leading to hemolytic uremic syndrome (HUS) via Shiga toxin (Stx). During HUS pathogenesis, EHEC O157:H7 is phagocytized by intestinal macrophages, although only a small proportion of internalized bacteria survive within the phagosome. To investigate this persistence, we performed global RNA-seq analysis of intracellular EHEC O157:H7 within murine macrophage phagosomes, complemented by in vitro assays simulating key phagosomal stressors. Our results reveal that EHEC employs a sophisticated survival strategy characterized by metabolic reprogramming and stress resistance. Inside macrophages, EHEC activates the SOS pathway, synthesizes membrane lipids, and engages NO detoxification mechanisms while repressing energetically costly virulence systems -motility, Type 3 Secretion System (T3SS), and Type 6 Secretion System (T6SS)-to prioritize survival. Notably, Shiga toxin gene regulation proved highly context-dependent: phagocytosis selectively upregulated the stx2a A subunit via the SOS response, whereas stx1a remained uninduced, likely restrained by NO-mediated repression. In contrast, under in vitro multi-stress conditions (pH 4.5) engaged the AR2-AR5 acid resistance systems and triggered robust expression of both stx1a subunits (A and B). These findings highlight the dynamic, stress-specific regulatory networks EHEC relies on to persist within the host.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13553990/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148910559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Turnover of microbial specialists and generalists shapes deterministic assembly and network stability along a salinity-alkalinity gradient in inland wetland soils.","authors":"Jie Wei, Fan Chang, Haomin Yang, Yan Sun, Zhi Li, Jun Li, Nannan Liu, Zhuan Hao","doi":"10.1007/s42770-026-02073-w","DOIUrl":"10.1007/s42770-026-02073-w","url":null,"abstract":"<p><p>Salinity-alkalinity gradients impose strong environmental filtering on soil microbial communities, yet the respective roles of generalist and specialist taxa in community assembly and stability remain insufficiently understood in wetland ecosystems. Here, bacterial and fungal communities were investigated across low, moderate, and high saline-alkaline zones in the Luyang Lake wetland, China. Amplicon sequencing was integrated with niche breadth analysis, community assembly inference, co-occurrence network analysis, cohesion metrics, and partial least squares path modeling to assess how generalists and specialists responded to environmental variation and contributed to microbial stability. Bacteria contained a larger generalist pool, whereas fungi were relatively enriched in specialists. Generalists were positively associated with nutrient availability and negatively associated with saline-alkaline stress, while bacterial specialists showed the opposite trend. Niche breadth decreased with increasing salinity-alkalinity, especially in bacteria, and this narrowing was accompanied by stronger deterministic assembly, mainly homogeneous selection. Network analysis further suggested that generalists contributed more to overall community connectivity, whereas specialists became more important for network organization under stronger saline-alkaline stress. Path modeling indicated that bacterial and fungal community stability was associated with distinct response pathways. Overall, salinity-alkalinity reorganized microbial communities by reducing niche breadth, strengthening deterministic assembly, and shifting the relative contributions of generalists and specialists to community stability. These findings improve our understanding of how niche strategy mediates microbial assembly and stability in saline-alkaline wetland soils.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13550284/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148905148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of fermentation parameters and mutagenesis of Glarea lozoyensis ATCC 20868 towards pneumocandin B₀ production.","authors":"Anshu Baldia, Manish Kumar, Deepanshi Rajput, Kashyap Kumar Dubey","doi":"10.1007/s42770-026-02079-4","DOIUrl":"10.1007/s42770-026-02079-4","url":null,"abstract":"<p><p>Pneumocandin B₀ is a secondary metabolite that acts as a precursor for caspofungin acetate, an antifungal drug. This study focuses on the development of an upstream process for pneumocandin B₀ production through fermentation condition optimization and mutagenesis. A response surface methodology (RSM)-based central composite design (CCD) was employed to increase the production of pneumocandin B₀ in Glarea lozoyensis ATCC 20868. The four independent variables (mannitol, fructose, soybean meal, and pH) were chosen at three different levels to obtain the optimum conditions for pneumocandin B₀ production. The optimized process conditions using RSM-CCD resulted in 29.4 mg/L pneumocandin (11.76-fold increase compared with that of wild-type). To improve pneumocandin B₀ production, mutagenesis (physical/chemical) was also performed using gamma-irradiation and methyl methane sulfonate (MMS). The best-performing MMS-induced mutant strain in optimized medium resulted in increased pneumocandin B_0, i.e., 74.17 mg/L (29-fold increase compared with that of wild-type), at the 2-L shake flask level. Additionally, morphological analysis using scanning electron microscopy revealed significant structural changes in the mutant strains, including altered hyphal and mycelial morphology. These findings suggest that mutagenesis not only enhances production but also modifies cellular physiology. In conclusion, this study presents an integrated strategy that combines media optimization and mutagenesis to significantly increase pneumocandin B₀ production.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13550391/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148905051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Occurrence and antimicrobial resistance profile of Listeria monocytogenes isolated from chilled processed meat products in the Metropolitan Region of Recife, Brazil.","authors":"Anízia Maria Vieira de Souza Lapenda, Eduarda Faria Raymundo, Pedro Marinho de Carvalho Neto, Rinaldo Aparecido Mota, José Wilton Pinheiro Junior, Andrea Paiva Botelho Lapenda de Moura","doi":"10.1007/s42770-026-02070-z","DOIUrl":"10.1007/s42770-026-02070-z","url":null,"abstract":"<p><p>The presence of Listeria monocytogenes in food represents a major challenge to food safety, especially in ready-to-eat products stored under refrigeration. This risk is associated with the ability of the pathogen to survive and multiply during prolonged refrigerated storage, making these foods potential sources of infection and a relevant public health concern. In this context, the aim of this study was to investigate the presence of Listeria monocytogenes in chilled processed meat products sold in bulk in the Metropolitan Region of Recife, PE, Brazil, as well as to evaluate the antimicrobial susceptibility profile of the isolates. A total of 48 samples of sausages and ham from different brands were analyzed, obtained from public markets and supermarkets in the region. Detection of Listeria spp. was performed using conventional methods recommended by the Ministry of Agriculture and Livestock, and antimicrobial susceptibility was assessed by the disk diffusion method. Of the analyzed products, 27/48 (56.25%) samples were positive for Listeria spp. by bacterial isolation. Among these, 15/48 (31.25%) were confirmed as L. monocytogenes. In the disk diffusion assay, one L. monocytogenes isolate showed a multidrug-resistant profile to vancomycin, amoxicillin, ampicillin, and ciprofloxacin. Additionally, among the Listeria spp. isolates, 6/27 (22.22%) showed resistance to at least one of the tested antimicrobials, with emphasis on ciprofloxacin (11.1%). These results demonstrate the presence of Listeria spp. and L. monocytogenes in commercially available chilled processed meat products, highlighting the importance of microbiological monitoring of these foods and surveillance of antimicrobial resistance profiles.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13545191/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148891064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"One Health in hospital settings: the role of water as an invisible reservoir of opportunistic pathogens.","authors":"Emilly Brito Ferreira, Jean Lopes da Silva, Monica de Souza Ferreira de Mattos, Hilton Vizi Martinez, Eduardo Jorge Pilau, Maria Cristina Bronharo Tognim, Fabrícia Gimenes, Miguel Machinski Junior, Benício Alves de Abreu Filho","doi":"10.1007/s42770-026-02078-5","DOIUrl":"10.1007/s42770-026-02078-5","url":null,"abstract":"<p><strong>Objectives: </strong>To evaluate the microbiological quality of a hospital's treated water distribution system, characterize opportunistic bacterial isolates and their antimicrobial susceptibility profiles, investigate the genetic relatedness between environmental and clinical isolates from a One Health perspective.</p><p><strong>Study design: </strong>Prospective observational study.</p><p><strong>Methods: </strong>A total of 352 water samples were collected over six months from strategic locations within a public teaching hospital. Samples were analyzed for total coliforms, Escherichia coli, heterotrophic bacteria (HB), bacterial isolation and identification, antimicrobial susceptibility testing, and ERIC-PCR genotyping was applied to Pseudomonas aeruginosa isolates to analyse their similarity with clinical isolates. Statistical analysis used the chi-square test of independence (χ²).</p><p><strong>Results: </strong>Despite legal compliance for coliforms, elevated HB counts were found in 17% of water tank samples and 12% of ICU samples. Pathogens such as Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Enterobacter spp. were isolated. Enterobacter spp. isolates exhibited resistance to multiple β-lactams. Genotypic analysis did not reveal a direct clonal relationship between P. aeruginosa isolates from water and NDM-producing P. aeruginosa isolates recovered from hospitalized patients.</p><p><strong>Conclusions: </strong>Although the hospital water distribution system complied with current microbiological potability standards, opportunistic bacteria were detected in localized areas of the network. The absence of clonal relatedness between environmental and clinical P. aeruginosa isolates suggests that the water system was not an active source of dissemination during the study period. These findings support the value of routine environmental surveillance as part of infection prevention strategies within a One Health framework.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13545182/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148891134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction: An experimental multiplex PCR/RT-PCR for detection of the main viruses associated with equine neurological disease.","authors":"S O Scherer, J V J Silva Júnior, N H Pedroso, I F Dionisio, R Weiblen, E F Flores","doi":"10.1007/s42770-026-02082-9","DOIUrl":"10.1007/s42770-026-02082-9","url":null,"abstract":"","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13542003/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148886356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phenotypic and molecular detection of efflux pump and expression profiling genes in Klebsiella pneumoniae exposed to ciprofloxacin and amoxicillin/clavulanic acid.","authors":"Fatima Amer Abd Algabar, Athmar Adnan Hakman, Mudhar A Al-Obaidi","doi":"10.1007/s42770-026-02075-8","DOIUrl":"10.1007/s42770-026-02075-8","url":null,"abstract":"<p><strong>Background: </strong>One of the main strategies Gram-negative bacteria employ to lower internal antibiotic concentrations is efflux. By identifying and eliminating a variety of harmful substances, including antibiotics, these active transport systems help bacteria become less susceptible to drugs and develop new resistance mechanisms. Efflux pumps are involved in bacterial stress response, pathogenicity, biofilm formation, and host physiology alteration in addition to offering an escape from antibacterial chemicals.</p><p><strong>Objective: </strong>This research is designed to study the prevalence of efflux pump genes and the measure expression of )AcrAB, MarA, MdtK OmpK35 and OmpK36 genes before and after treatment with combination of Ciprofloxacin (CIP) and Amikacin (AMC) antibiotic CIP of Klebsiella pneumoniae isolated from hospitalized patients in Iraq hospitals.</p><p><strong>Materials and methods: </strong>During a six-month cross-sectional survey (January-June 2025), twenty K. pneumoniae strains were collected from patients admitted to several teaching hospitals. Their antimicrobial sensitivity was determined by applying the agar-based disk diffusion assay. The ethidium bromide (EtBr) agar cartwheel method can be used to phenotypically detect the activity of efflux pumps in K. pneumoniae isolates. The PCR method was used to determine the frequency of genes encoding AcrAB, marA, mdtK, ompK35, and ompK36 in K. pneumoniae, and the Real-time PCR method was used to determine the expression of the efflux pump gene exposed to ciprofloxacin and amoxicillin.</p><p><strong>Results: </strong>The findings indicate that 90% of K. pneumoniae phenotypically displayed resistance to tetracycline, 90% amoxicillin/clavulanic acid, 90% piperacillin, 90% ciprofloxacin, and 89%. All the Klebsiella isolates show fluorescence under UV light at varying concentrations of ethidium bromide, indicating efflux pump activity. The higher prevalence of AcrAB and MarA genes100%. A multidrug efflux pump-associated gene is identified among the isolates. Moreover, the porin genes OmpK35 and OmpK36 are observed in 66.66% of the samples. In contrast, only 50% of the K. pneumoniae strains harbored the MdtK efflux pump gene. However, the analysis show that 50% of the isolates carry the MarkD gene, which play crucial roles in biofilm formation. The expression of AcrAB, MarA, MdtK ompK35 and OmpK36 genes is higher and exposed to ciprofloxacin and amoxicillin.</p><p><strong>Conclusions: </strong>The efficacy of synergistic antibiotic and efflux pump inhibitor combinations in eradicating MDR bacterial resistance is an encouraging discovery.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13538341/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148879163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Whole genome sequencing analysis and functional characterization of Lacticaseibacillus rhamnosus HP-B1083.","authors":"Da-Hu Zhang, Zhen-Dong Tian, Bao-Zhi Ge, Qian-Meng Qi, Jia-Lin Lv, Hang Wu, Shao-Yang Hou, Shu-Hang Zhang","doi":"10.1007/s42770-026-02066-9","DOIUrl":"10.1007/s42770-026-02066-9","url":null,"abstract":"<p><p>Lacticaseibacillus rhamnosus is an important strain for the biotransformation of natural products, and its crude extract exhibits biotransformation effect on glycosidic compounds such as baicalin. To further explore the potential of this strain, particularly given its previously demonstrated high-efficiency β-glucuronidase activity for baicalin conversion, whole-genome sequencing and functional annotation of Lacticaseibacillus rhamnosus HP-B1083 were performed in this study, and its acid tolerance, bile salt tolerance, short-term heat resistance and antibacterial activity were evaluated. The results showed that the strain possessed a circular chromosome with a full length of 3,090,505 bp and a GC content of 46.69%. Gene annotation revealed that the genome contained 2941 coding sequences (CDS) and 112 non-coding RNA genes, including 60 tRNA genes, 1 tmRNA gene, 36 misc_RNA genes and 15 rRNA genes. The functional annotations further reveal that this genome is rich in genes related to carbohydrate metabolism, hydrolases, and transferases, which is highly consistent with its phenotypic characteristics in glycoside transformation and the synthesis of antibacterial substances. In addition, acid tolerance, bile salt tolerance and short-term heat resistance experiments verified that HP-B1083 had acid resistance, bile salt resistance and short-term heat resistance. Antibacterial activity tests confirmed that HP-B1083 produced inhibition zone diameters over 10 mm against common foodborne pathogenic bacteria such as Escherichia coli and Bacillus cereus. Therefore, Lacticaseibacillus rhamnosus HP-B1083 has important application prospects in the development of functional foods, preparation of enzyme preparations and pharmaceutical industry.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13534402/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148872990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Use of beneficial microorganisms in bean cultivation: strategies employed to increase productivity.","authors":"Matheus Messias, Jerri Édson Zilli, Luis Henrique de Barros Soares, Enderson Petrônio de Brito Ferreira, Veronica Massena Reis","doi":"10.1007/s42770-026-02074-9","DOIUrl":"10.1007/s42770-026-02074-9","url":null,"abstract":"<p><p>The common bean is of great importance for human nutrition worldwide as its grain is a cheap source of protein, but it has a high-cost production system due to the use of synthetic inputs such as nitrogen fertilizers and pest and disease control products. An alternative to promote the sustainability of the production system and increase crop productivity is the use of co-inoculation of plant growth-promoting rhizobacteria (PGPR) to reduce and/or replace the use of nitrogen fertilizers and pest and disease control products. Since 2010, Brazil has stood out on the international stage with research focused on the application of rhizobia combined with PGPR in bean crops. Currently, the use of microorganisms that effectively promote plant growth through different mechanisms of action is already a consolidated reality in Brazil, with experimental results proven by years of research. Despite these advances, there are still challenges to overcome to maximize the potential of co-inoculation in bean crops. These include the need to develop more efficient formulations containing elite microbial strains and optimized microbial consortia, as well as the search for inoculation methods that optimize root colonization by the bacteria and maximize their beneficial effects on the plant. In this review, we discuss the history of common-bean production and the types and doses of inoculants marketed, as well as the challenges for the efficiency of co-inoculation and for the development of inoculants of rhizobial consortia with PGPRs for the common-bean cultivation.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13530100/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148863404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative analysis of proteolytic activity in lactic and propionic acid bacteria: substrate specificity and complementary effects in dairy fermentation.","authors":"Tatsiana Halavach, Vladimir Kurchenko, Natallia Zhabanos, Natallia Furyk, Ivan Evdokimov, Alexey Lodygin, Mariya Shramko, Andrey Nagdalian","doi":"10.1007/s42770-026-02067-8","DOIUrl":"10.1007/s42770-026-02067-8","url":null,"abstract":"<p><p>This study presents novel insights into the proteolytic activity of lactic acid bacteria (LAB) and their combinations with propionic acid bacteria (PAB), addressing the current gap in understanding the mechanisms of milk protein hydrolysis during dairy fermentation. The research involved a comprehensive analysis of 12 strains of Lactococcus spp. and 4 strains of Streptococcus spp., along with their combinations with PAB. Using SDS-PAGE electrophoresis, spectrophotometry, and high-performance liquid chromatography, the study investigated the proteolytic characteristics of these microorganisms during skim milk fermentation. Key findings revealed distinct patterns of protein hydrolysis. Preferential cleavage of β-casein was shown for the L. lactis 782 M-A proteolytic system, whereas S. thermophilus 1095 ST-AV, Propionibacterium sp. 2388 MYO-К and L. casei 1188 ML-OF hydrolysed α- and β-casein. However, whey proteins were not found to be proteolysed. Notably, the combination of PAB with lactococci demonstrated enhanced casein hydrolysis compared to individual strains. The research identified varying levels of proteolytic activity among different strains. The maximum proteolytic activity recorded was 2.54-3.12 mg/ml for Propionibacterium sp. 2388 MYO-K. The most significant finding was the complete hydrolysis of the casein fraction observed when milk was fermented by PAB in combination with lactococci or the L. lactis 782 M-A and S. thermophilus 1095 ST-AV combination. The results obtained can be applied to optimize fermentation processes and develop functional dairy products with tailored protein-peptide profiles. The results contribute to a better understanding of how to select appropriate bacterial strains for specific dairy fermentation processes based on their proteolytic characteristics.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13530073/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148863423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}