INTRODUCTIONPathogenic microorganisms resistant to traditionalantibiotics are a serious problem of modern healthcare.There is evidence that over 70% of all pathogenicbacteria are resistant to at least one of the mostcommonly used antibiotics. Therefore, there is an urgentneed for new drugs and therapeutic approaches toovercome their resistance [1–5].Antimicrobial peptides produced by variousorganisms from bacteria to mammals are an idealalternative to antibiotics due to their antimicrobial, antiinflammatory,angiogenic, and immunomodulatoryproperties, as well as low bacterial resistance [6].However, their use is limited by toxicity and stabilityin vivo [7].Antimicrobial peptides act against various types ofpathogens, including gram-positive and gram-negative28Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39bacteria, viruses, and microscopic fungi, through thedestruction of the cytoplasmic membrane, intracellularpenetration, and immunomodulation [8, 9]. Structurally,antimicrobial peptides are classified into linear cationicamphipathic peptides and macrocyclic peptides [10].As a rule, antimicrobial peptides are short peptidesconsisting of 10–50 amino acids [11, 12]. They havecommon features despite differing in length, amino acidsequences, and conformation [13]. Typical antimicrobialpeptides are composed of positively charged residuessuch as arginine, lysine, and histidine [14]. Cationicpeptides with a positive charge ranging from +2 to +11can interact with the membranes of microbial cells.Besides, a significant part of antimicrobial peptidesis hydrophobic, contributing to the formation ofamphipathic secondary or quaternary structures [15].Antimicrobial peptides have several advantagesover traditional antibiotics [16]. First of all, they havea broad spectrum of antimicrobial activity, againsteven multidrug-resistant pathogens [8, 16]. Secondly,antimicrobial peptides are highly active against gramnegativebacteria, which are more serious targets thangram-positive bacteria [17]. Another advantage is arather low likelihood of drug resistance.Bacteriocins are antimicrobial, ribosomallysynthesized peptides of bacteria with a low molecularweight [18]. Mostly studied are bacteriocins producedby lactobacilli. They can be roughly divided into fourcategories: lantibiotics (e.g., nisin); non-antibioticbacteriocins with good activity against Listeriamonocytogenes, as well as pediocins, which make upthe largest group; thermosensitive macromolecularproteinaceous bacteriocins; and complex bacteriocinswith carbohydrates, lipids, and proteins [19–23]. Of allwell-studied bacteriocins of lactobacilli, only nisin isproduced commercially [24].Potential sources of bacteria producing bacteriocinsare dairy products, cow rumen, feed, as well as naturalobjects such as soils, plant waste, rhizosphere of plants,bottom sediments of water bodies, etc. [18, 25, 26].In our previous studies, we isolated 19 microorganismsfrom the natural sources of Kemerovo Region(Siberian Federal District, Russia), including 10 speciesof bacteria (Geobacillus, Bacillus, Lactobacillus,Leuconostoc, and Pediococcus) that showed highantimicrobial activity against Escherichia coli, Salmonellaenterica, Staphylococcus aureus, Pseudomonasaeruginosa, Bacillus mycoides, Candida albicans, andPenicíllium citrinum [27–29].In this study, we aimed to examine the structureand properties of antimicrobial peptides produced byantagonist microorganisms isolated from the naturalobjects in Siberia.STUDY OBJECTS AND METHODSOur study objects were bacteria isolated from thenatural sources of Kuzbass (Table 1).Microorganism cultures. To obtain enrichmentcultures of microorganisms, we crushed the samplesof soil, bottom sediments, and plant waste understerile conditions and rubbed their small amounts onPetri dishes with nutrient agar. The Petri dishes wereincubated for three days at 26°C. Two nutrient mediawere used: lactobacilli were cultured on MRS agar;Bacillus and Geobacillus bacteria were cultured ona medium (pH 7.4 ± 0.2) containing 10.0 g/L caseinhydrolysate, 2.5 g/L yeast extract, 5.0 g/L glucose,2.5 g/L potassium hydrogen phosphate, and 12.0 g/Lbacteriological agar.Pure cultures of microorganisms were obtainedfrom enrichment cultures by streaking. Microorganismswere cultivated on the media described above for 24 h:Lactobacillus, Leuconostoc and Pediococcus bacteria at37°C, and Bacillus and Geobacillus at 30°C.At the end of cultivation, cell debris was removedfrom all suspension cultures. The cultures werecentrifuged at 3900 rpm in plastic flasks. The resultingsupernatant was dried in a Labcocnco Triad freezedryer (Labcocnco, USA) at a freezer temperature of–80°С, supernatant temperature of –20°С, and 0.05 mbarvacuum.Protein fractions. To separate protein intoindividual fractions, the dried biomass was dissolved in1 mL of 0.25 M phosphate buffer and the total proteinwas precipitated by adding 2 mL of concentratedTable 1 Study objectsMicroorganism Reference Source of isolationBacillus subtilis Bs-1 Soil (Peshcherka village, Kemerovo district)Lactobacillus plantarum Lp-7 Rhizosphere of plants (Voznesenka village, Yaya district)Leuconostoc mesenteroides Lm-8Pediococcus acidilactici Pa-9 Rhizosphere of plants (Ursk village, Guryevsk district)Pediococcus pentosaceus Pp-11 Plant waste at Sukhovsky farm (Kemerovo city)Lactobacillus casei Lc-12Lactobacillus fermentum Lf-13 Plant waste at Niva farm (Gorskino village, Guryevsk district)Pediococcus damnosus Pd-16 Plant waste at Veles farm (Yaya village, Yaya district)Geobacillus stearothermophilus Bs-19 Bottom sediments of the Kara-Chumysh reservoir (Prokopyevsk district)Bacillus caldotenax Bc-20 Bottom sediments of Lake Udai (Mariinsk district)29Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39ammonium sulfate solution. The resulting proteinsuspension was separated by centrifugation at 8000 rpm.The protein precipitate was dissolved in 1 mL of0.025 M Tris buffer solution (pH 4.5). The precipitatewas applied to an Enrich 650 10 mm X 300 mm column(Biorad, USA) for a gel permeation high performanceliquid chromatography (HPLC) at 280 nm using a directinjection system. Fractionation was performed using anNGC fraction collector (Biorad, USA).Additionally, each protein fraction was purifiedon hydrophobic Amberlite XAD X-6 resins bychromatography. A glass column was filled with 10 gof Amberlite XAD-2 resin equilibrated with 10 mL of20 mM trifluoroacetic acid solution. A protein solutionin an acetate buffer was applied to the column andeluted in a methanol gradient from 0 to 15%, with agradient rise of 5% for every 10 fractions. Fractionscontaining proteins were determined by taking 50 μLof each fraction and mixing it with a solution ofBradford’s reagent in a 1:1 ratio. The resultingsolution was measured on a Biorad SmartSpec PlusSpectrophotometer (USA). Fractions with an opticalabsorption of 0.06 or more were selected for furtherdrying and identifying the amino acid sequence bythe MALDI-TOF method using a MALDI TOF/TOFBRUKER Autoflex Speed mass spectrometer (BrukerCorporation, USA)Trypsinolysis. Peptides were precipitated by addingan equal volume of methanol/chloroform mixture to analiquot of a 200 μL fraction. The resulting precipitatewas separated by centrifugation at 4000 rpm. Theprecipitate was dissolved in 100 μL of 6 M urea solution,to which 5 μL of dithiothreitol (DTT) solution wasadded to keep for 60 min at room temperature. Then,we added 20 μL of iodoacetamide solution and kept themixture for 60 min at room temperature. After that, weadded 20 μL of a DTT solution and kept the mixtureagain for 60 min at room temperature. After adding775 μL of MiliQ H2O and 50 μL of trypsin solution,the mixture was stirred by pipetting and kept in athermostat at 37°C for 12 h. The enzyme was inactivatedby adding 10 μL of trifluoroacetic acid. The peptideswere purified by chromatography on C18 cartridges.The reaction mixture was applied to a cartridge andeluted with a solution of 0.1% trifluoroacetic acid in a1:1 H2O/acetonitrile mixture. Analysis and Top-Dawnsequencing were performed on 1 μL of a purified peptidesolution.The antibacterial properties of the peptidesagainst Bacillus pumilus and Escherichia coli weremeasured by the disk diffusion method. For this, weused suspensions of night cultures grown on a standardliquid nutrient LB medium with a titer of 0.5. Thenumber of microorganisms (titer) in the suspension wasdetermined by optical density at 595 nm. 200 μL ofthe pathogen culture was dropped onto a 90 mm Petridish, rubbed with a sterile spatula by the spread platemethod, and left to dry for 20 min under a laminarwith the lid ajar. Then, 0.5 cm sterile filter disks soakedin the peptide solutions under study and dried at roomtemperature for 10 min were placed on the Petri dishesin the radial direction. The Petri dishes were left for30 min at room temperature and then incubated ina thermostat at 37°C for 12 h. Then, we identified abacterial inhibition zone around the disc and measuredits diameter with a vernier caliper. Ampicillin at aconcentration of 5 mg/mL was used as a positive control,and a disc soaked in a liquid medium was used as anegative control.The fungicidal activity of the peptides againstthe microscopic fungi Aspergillus flavus andAspergillus niger was measured by the disk diffusionmethod. The fungi were cultivated for 7 days, withan inoculation density of 6×107 conidia per 1 mL ofmedium. The results were analyzed with time intervals(3, 9, 12, 24, 48, 72 h, etc.) and by the fungus growthphase (stationary, accelerated growth, logarithmic),i.e., during the periods of exponential cell growth,decreased growth, and death or autolysis. At the end ofthe incubation, the inhibition zone around the disc wasmeasured with a vernier caliper (mm), which indicatedthe degree of biocidal activity or its absence. A negativecontrol was the samples with filters impregnatedwith the medium, and a positive control was thepharmaceutical preparation Irunin® (Veropharm,Russia) with itraconazole as an active ingredient.Statistical data were analyzed in Microsoft OfficeExcel 2007. All the experiments were carried out intriplicate. Statistical analysis was performed usinga one-sample Student’s t-test. The differences wereconsidered statistically significant at P < 0.05.Table 2 Peptides from the biomass of bacteria isolated fromnatural sources of KuzbassMicroorganism IsolatedfractionsMicroorganism IsolatedfractionsBs-1 Bs-1_1 Lc-12 Lc-12_1Lp-7 Lp-7_1 Lf-13 Lf-13_1Lf-13_2Lf-13_3Lm-8 Lm-8_1 Pd-16 Pd-16_1Lm-8_1 Pd-16_2Pd-16_3Pd-16_4Pa-9 Pa-9_1 Bs-19 Bs-19_1Pa-9_2 Bs-19_2Pp-11 Pp-11_1 Bc-20 Bc-20_1Pp-11_2Pp-11_3Pp-11_4Pp-11_5Pp-11_6Pp-11_7Pp-11_830Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39RESULTS AND DISCUSSIONSeveral protein fractions were isolated from theculture fluid of all the studied samples (Table 2).According to Table 2, one protein fraction wasisolated from the culture fluid of Bacillus subtilis,Lactobacillus plantarum, Lactobacillus casei, andBacillus caldotenax; two protein fractions fromLeuconostoc mesenteroides, Pediococcus acidilactici,and Geobacillus stearothermophilus; three proteinfractions from Lactobacillus fermentum; four proteinfractions from Pediococcus damnosus; and eight proteinfractions from the Pediococcus pentosaceus culturefluid.The results of the MALDI TOF mass spectrometryof protein fractions are presented in Figures 1–7. Wefound some identical mass spectra of protein fractionssynthesized by different bacteria.Figure 1 Mass spectrum of fraction Bs-1_1Figure 2 Mass spectrum of fraction Bc-20_1 (Lf-13_1, Lf-13_2, Lf-13_3)31Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39Having analyzed the mass spectra, we determinedthe molecular masses and amino acid sequences of sevenpeptides (Table 3).Table 3 also shows the presence of analogues for thestudied peptides in the PepBank and Uniprot databases.We established a homology of fractions Pp-11_1, Pp-11_2, Pp-11_3, Pp-11_4, Pp-11_5, Pp-11_6, Pp-11_7, Pp-11_8, Lp-7_1, Pd-16_1, Pd-16_2, Pd-16_3, and Pd-16_4with the cysteine membrane protein Giardia lamblia P15(Fig. 8), as well as a homology of peptides Pa-9_1 andPa-9_2 with the Planctomycetes bacterium I41 peptides(Fig. 9). The rest of the peptides had no analogues in thePepBank and Uniprot databases.Figure 3 Mass spectrum of fraction Bs-19_1 (Lc-12_1)Figure 4 Mass spectrum of fraction Bs-19_2The antibacterial properties of the studied peptidesagainst gram-positive (Bacillus pumilus) and gramnegative(Escherichia coli) bacteria, as well as theirfungicidal properties against the microscopic fungiAspergillus niger and Aspergillus flavus are presented inTables 4–5 and Figs. 10–11.According to Table 4 and Fig. 10, of the sevenpeptides under study, only one (Bs-19_2) exhibitedno antagonistic activity against E. coli and B. pumilusstrains. Peptide fraction Pp-11_1 (and peptides withidentical amino acid sequences Pp-11_2, Pp-11_3, Pp-11_4, Pp-11_5, Pp-11_6, Pp-11_7, Pp-11_8, Pd-16_1,Pd-16_2, Pd- 16_3, Pd-16_4, and Lp-7_1) showed32Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39high antagonism against B. pumilus and pronouncedantibacterial activity against E. coli. Peptides Bs-1_1and Bc-20_1 (identical Lf-13_1, Lf-13_2, and Lf-13_3),Lm-8_1 (identical Lm-8_2), and Pa-9_1 (identicalFigure 5 Mass spectrum of fraction Pp-11_1 (Pp-11_2, Pp-11_3, Pp-11_4, Pp-11_5, Pp-11_6, Pp-11_7, Pp-11_8, Lp-7_1, Pd-16_1,Pd-16_2, Pd-16_3, Pd-16_4)Figure 6 Mass spectrum of fraction Lm-8_1 (Lm-8_2)Pa-9_2) had moderate and pronounced antagonisticactivity against B. pumilus, but no activity againstE. coli. Finally, peptide Bs-19_1 (identical Lc-12_1)showed bacteriostatic activity only against E. coli.33Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39Figure 7 Mass spectrum of fraction Pa-9_1 (Pa-9_2)Table 3 Molecular masses and amino acid sequences of peptides from the culture fluid of bacteria isolated from the natural sourcesof KuzbassCodeof peptideMolecularmass ofpeptide, DaAmino acid sequence Analoguesin PepBankor UniprotBs-1_1 13140.97 AFGKHVLIPVSCGFTYVWKCTLIPHISARPHYCFHRQHCDYKINQVSFEDAWHTPCNo analoguesBc-20_1Lf-13_1Lf-13_2Lf-13_36577.63 FLAFAYLPIPGWHPDYNGRAMKWANRPFTYICHGRDLKLRQMLYSGATIGHAEMRNo analoguesBs-19_1Lc-12_16572.00 PHQGHAFNFSCDMETAGFKGTQFWTFKSVSPHLATFKLGHMSTYAILGFAGCHNo analoguesBs-19_2 6290.80 FVKGFHPSMTARGVVSDEADGRCDRFVKGFHPSMTARGVVSDEADGRCDRNo analoguesPp-11_1Pp-11_2Pp-11_3Pp-11_4Pp-11_5Pp-11_6Pp-11_7Pp-11_8Lp-7_1Pd-16_1Pd-16_2Pd-16_3Pd-16_42061.66 VMCLARKCSQGLIVKAPLM High homologywith cysteinemembraneprotein Giardialamblia P15Lm-8_1Lm-8_235571.18 MOPRKLCQSP VAILKMCVPA RQKVPSILKM OPRKLCQSPV AILKMCVPARQKVPSILKMO PRKLCQSPVAILKMCVPARQ KVPSILKMOP RKLCQSPVAILKMCVPARQK VPSILKMOPR KLCQSPVAIL KMCVPARQKV PSILKMOPRKLCQSPVAILK MCVPARQKVP SILKMOPRKL CQSPVAILKM CVPARQKVPSILKMOPRKLC QSPVAILKMC VPARQKVPSILKMOPRKLCQ SPVAILKMCVPARQKVPSIL KMOPRKLCQS PVAILKMCVP ARQKVPSILK MOPRKLCQSPVAILKMCVPA RQKVPSILKNo analoguesPa-9_1Pa-9_22587.21 AVPSMKLCIQWSPVRASPCVMLGI High degree ofhomology withPlanctomycetesbacterium I41peptides34Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39Figure 9 The closest analogues for peptides Pa-9_1 and Pa-9_2 according to BLAST NCBIFigure 8 The closest analogues for peptides Pp-11_1, Pp-11_2, Pp-11_3, Pp-11_4, Pp-11_5, Pp-11_6, Pp-11_7, Pp-11_8, Lp-7_1,Pd-16_1, Pd-16_2, Pd-16_3, and Pd-16_4 according to BLAST NCBITable 4 Antibacterial properties of peptides from the culturefluid of bacteria isolated from the natural sources of Kuzbass(M ± m)Peptide code Test strain Lysis zonediameter, cmDegreeof activityNegativecontrolEscherichia coli 0 –Bacillus pumilus 0 –Ampicillin(positivecontrol)0.5 mg/mLEscherichia coli 0.90 ± 0.05 –Bacillus pumilus 2.40 ± 0.10 –Bs-1_1 Escherichia coli 0 AbsentBacillus pumilus 0.60 ± 0.03 ModerateBc-20_1Lf-13_1Lf-13_2Lf-13_3Escherichia coli 0 AbsentBacillus pumilus 0.80 ± 0.04 PronouncedBs-19_1Lc-12_1Escherichia coli 0.60 ± 0.03 ModerateBacillus pumilus 0 AbsentBs-19_2 Escherichia coli 0 AbsentBacillus pumilus 0 AbsentPp-11_1Pp-11_2Pp-11_3Pp-11_4Pp-11_5Pp-11_6Pp-11_7Pp-11_8Pd-16_1Pd-16_2Pd-16_3Pd-16_4Lp-7_1Escherichia coli 0.70 ± 0.04 PronouncedBacillus pumilus 1.00 ± 0.05 HighLm-8_1Lm-8_2Escherichia coli 0 AbsentBacillus pumilus 0.70 ± 0.04 PronouncedPa-9_1Pa-9_2Escherichia coli 0 AbsentBacillus pumilus 0.60 ± 0.03 ModerateUnlike biocidal properties, which do not dependon the pathogen growth phase and naturally decreaseover time, fungicidal properties need to be determinedat each stage of the fungus life cycle since fungalpathogens have a complex growth cycle. We found thatthe peptide fractions under study did not stop fungalgrowth, but only inhibited it, which was indicated by achange in the mycelium color. The results were analyzedwith time intervals (3, 9, 12, 24, 48, 72 h, etc.) and bythe fungus growth phase (stationary, accelerated growth,logarithmic), i.e., during the periods of exponential cellgrowth, decreased growth, and death or autolysis. Thesamples with filters impregnated with a nutrient mediumwere used as a control.Having analyzed the peptides’ fungicidal activity(Table 5, Fig. 11), we identified those peptides whichcould inhibit Aspergillus growth, rather than stop itcompletely. They were Bs-1_1, Bc-20_1 (identicalLf-13_1, Lf-13_2, and Lf-13_3) and Bs-19_2, with alysis zone diameter of 0.1–0.2 mm. The maximumfungicidal activity against A. niger (0.3–0.5 mm lysiszone) was demonstrated by peptides Bs-19_1 (identicalLc-12_1), Pp-11_1 (identical Pp-11_2, Pp-11_3, Pp-11_4,Pp-11_5, Pp-11_6, p-11_7, Pp-11_8, Pd-16_1, Pd-16_2,Pd-16_3, Pd-16_4, and Lp-7_1), and Pa-9_1 (Pa-9_2). Thehighest activity against A. flavus (0.3–0.4 mm lysis zone)was revealed by peptides Pp-11_1 (identical Pp-11_2,Pp-11_3, Pp-11_4, Pp-11_5, Pp-11_6, p-11_7, Pp-11_8,Pd-16_1, Pd-16_2, Pd-16_3, Pd-16_4, and Lp-7_1), Lm-8_1 (identical Lm-8_2), and Pa-9_1 (identical Pa- 9_2).Based on the study of antimicrobial activity, weselected peptides with maximum antibacterial (againstB. pumilus) and fungicidal (against A. niger andA. flavus) properties: Pp-11_1 (identical Pp-11_2,Pp-11_3, Pp-11_4, Pp-11_5, Pp-11_6, p-11_7, Pp-11_8,Pd-16_1, Pd-16_2, Pd-16_3, Pd-16_4, and Lp-7_1 ), Lm-8_1 (identical Lm-8_2), and Pa-9_1 (identical Pa-9_2).35Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39Bs-1_1 Escherichia coli Bs-1_1 Bacillus pumilus Bc-20_1, Lf-13_1, Lf-13_2,Lf-13_3 Escherichia coliBc-20_1, Lf-13_1, Lf-13_2,Lf-13_3 Bacillus pumilusBs-19_1, Lc-12_1Escherichia coliBs-19_1, Lc-12_1Bacillus pumilusBs-19_2 Escherichia coli Bs-19_2 Bacillus pumilusPp-11_1, Pp-11_2,Pp-11_3, Pp-11_4,Pp-11_5, Pp-11_6,Pp-11_7, Pp-11_8, Lp-7_1,Pd-16_1, Pd-16_2,Pd-16_3, Pd-16_4Escherichia coliPp-11_1, Pp-11_2,Pp-11_3, Pp-11_4,Pp-11_5, Pp-11_6,Pp-11_7, Pp-11_8, Lp-7_1,Pd-16_1, Pd-16_2,Pd-16_3, Pd-16_4Bacillus pumilusPa-9_1, Pa-9_2Escherichia coliPa-9_1, Pa-9_2Bacillus pumilusLm-8_1, Lm-8_2Escherichia coliLm-8_1, Lm-8_2Bacillus pumilusAmp Escherichia coli Amp Bacillus pumilus– Escherichia coli – Bacillus pumilusFigure 10 Antibacterial properties of peptides fromthe culture fluid of bacteria isolated from the naturalsources of Kuzbass36Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39Bs-1_1 Aspergillus niger Bs-1_1 Aspergillus flavus Bc-20_1, Lf-13_1, Lf-13_2,Lf-13_3 Aspergillus nigerBc-20_1, Lf-13_1, Lf-13_2,Lf-13_3 Aspergillus flavusBs-19_1, Lc-12_1Aspergillus nigerBs-19_1, Lc-12_1Aspergillus flavusBs-19_2 Aspergillus niger Bs-19_2 Aspergillus flavusPp-11_1, Pp-11_2,Pp-11_3, Pp-11_4,Pp-11_5, Pp-11_6,Pp-11_7, Pp-11_8, Lp-7_1,Pd-16_1, Pd-16_2,Pd-16_3, Pd-16_4Aspergillus nigerPp-11_1, Pp-11_2,Pp-11_3, Pp-11_4,Pp-11_5, Pp-11_6,Pp-11_7, Pp-11_8, Lp-7_1,Pd-16_1, Pd-16_2,Pd-16_3, Pd-16_4Aspergillus flavusPa-9_1, Pa-9_2Aspergillus nigerPa-9_1, Pa-9_2Aspergillus flavusLm-8_1, Lm-8_2Aspergillus nigerLm-8_1, Lm-8_2Aspergillus flavusFigure 11 Fungicidal properties of peptides from the culturefluid of bacteria isolated from the natural sources of KuzbassThus, the fact that peptides produced by microorganismsinhabiting the natural ecosystems of Kuzbassexhibit antagonistic activity against opportunistic strainsopens up prospects for their use in the production ofpharmaceutical substances with antimicrobial action,alternative to traditional antibiotics.CONCLUSIONWe identified amino acid sequences and molecularmasses of peptide fractions produced by bacteria(Lactobacillus, Leuconostoc, Pediococcus, Bacillus,and Geobacillus) isolated from the natural objects ofthe Siberian region (soil, rhizosphere of plants, bottomsediments of reservoirs, and plant waste). In total,we isolated 25 protein fractions, some with identicalmass spectra. Thus, we obtained seven peptides withdifferent amino acid sequences, five of which haveno analogues in the PepBank and Uniprot databases.One of the peptides (VMCLARKCSQGLIVKAPLM,37Babich O.O. et al. Foods and Raw Materials, 2022, vol. 10, no. 1, pp. 27–39Table 5 Fungicidal properties of peptides from the culture fluid of bacteria isolated from the natural sources of Kuzbass (M ± m)Peptide code Lysis zone diameter by growth phase, mmExponential cellgrowth, hDecreased growth, h Death or autolysis, days3 9 12 48 72 6 12Aspergillus nigerBs-1_1 + + + 0.100 ± 0.005 0.200 ± 0.010 0.100 ± 0.005 0.100 ± 0.005Bc-20_1, Lf-13_1, Lf-13_2, Lf-13_3 + + + 0.200 ± 0.010 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005Bs-19_1, Lc-12_1 + + + 0.500 ± 0.025 0.500 ± 0.025 0.400 ± 0.020 0.400 ± 0.020Bs-19_2 + + + 0.100 ± 0.005 0.100 ± 0.005 0.200 ± 0.010 0.200 ± 0.010Pp-11_1, Pp-11_2, Pp-11_3, Pp-11_4, Pp-11_5, Pp-11_6, p-11_7, Pp-11_8, Pd-16_1,Pd-16_2, Pd-16_3, Pd-16_4, Lp-7_1+ + + 0.100 ± 0.005 0.200 ± 0.010 0.400 ± 0.020 0.400 ± 0.020Lm-8_1, Lm-8_2 + + + 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005Pa-9_1, Pa-9_2 + + + 0.100 ± 0.005 0.300 ± 0.015 0.400 ± 0.020 0.400 ± 0.020Aspergillus flavusBs-1_1 + + + 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005Bc-20_1, Lf-13_1, Lf-13_2, Lf-13_3 + + + 0.200 ± 0.010 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005Bs-19_1, Lc-12_1 + + + 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005Bs-19_2 + + + 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005Pp-11_1, Pp-11_2, Pp-11_3, Pp-11_4, Pp-11_5, Pp-11_6, p-11_7, Pp-11_8, Pd-16_1,Pd-16_2, Pd-16_3, Pd-16_4, Lp-7_1+ + + 0.100 ± 0.005 0.100 ± 0.005 0.300 ± 0.015 0.400 ± 0.020Lm-8_1, Lm-8_2 + + + 0.100 ± 0.005 0.300 ± 0.015 0.300 ± 0.015 0.400 ± 0.020Pa-9_1, Pa-9_2 + + + 0.100 ± 0.005 0.300 ± 0.015 0.400 ± 0.020 0.400 ± 0.020Positive control + + + 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.005 0.100 ± 0.0052061.66 Da) was homologous to the cysteine membraneprotein Giardia lamblia P15, and another one(AVPSMKLCIQWSPVRASPCVMLGI, 2587.21 Da)was homologous to the Planctomycetes bacterium I41peptides.The peptides obtained from the culture fluid ofbacteria isolated from natural sources of the SiberianFederal District were analyzed for antibacterialproperties against Bacillus pumilus and Escherichiacoli. We identified one peptide that exhibited noantagonistic activity against either gram-negative orgram-positive bacteria. One peptide fraction showedhigh antibacterial properties against both B. pumilus andE. coli. One peptide was active against E. coli, but notagainst B. pumilus (gram-positive bacteria). Finally, fourout of seven peptides under study exhibited moderateand pronounced antagonism against B. pumilus, but noantibacterial activity against E. coli.Our study of the peptides’ antifungal activityrevealed three peptides that could inhibit the growth ofthe microscopic fungi Aspergillus niger and Aspergillusflavus, without stopping it completely (0.1–0.2 mm lysiszone). Four peptide fractions showed high fungicidalactivity against Aspergillus (0.3–0.5 mm lysis zone).According to our results, antimicrobial peptidesproduced by bacteria isolated from the natural objects ofthe Siberian region can be used as promising agents inthe production of pharmaceutical substances and drugs(after safety trials) to treat infectious diseases, such asgastrointestinal, respiratory, blood and skin, as well asfungal infections.CONTRIBUTIONThe authors are equally responsible for the researchresults and the manuscript.CONFLICT OF INTERESTThe authors declare that there is no conflict ofinterest.