Paenibacillus Polymyxa Research Articles

Uji Efikasi Berbagai Media Agens Antagonis Paenibacillus polymyxa Terhadap Penyakit Bacterial Leaf Blight Pada Tanaman Padi (Oryza sativa)

An experiment was carried out in Margasari Village, Dawuan District, Subang Regency, from July 2020 to November 2020. The purpose of this study was to study the efficacy of various media of the antagonist agent Paenibacillus polymyxa in controlling Bacterial Leaf Blight in rice plants and to find the most effective and efficient media. to control Bacterial Leaf Blight in rice plants. The method used in this study was an experiment through field experiments, with a simple randomized block design consisting of six treatments and four replications. The experimental treatments consisted of: A (Sugar Potato Extract), B (Sweet Potato Extract), C (Sugar Cassava Extract), D (Soybean Extract), E (Sugar Rice Wash Water) and F (Control). The experimental results show that: (1) All the Paenibacillus polymyxa antagonist agent media in this experiment were effective in suppressing the intensity of the attack of Bacterial Leaf Blight (2) The more effective Paenibacillus polymyxa antagonist agent medium was treatment A (Sugar Potato Extract) which was able to suppress the intensity. attack was lower than the other treatments, so it had the most number of productive tillers and produced the highest average productivity of 8.08 tons ha-1.

Fusaricidin produced by the rhizobacterium Paenibacillus polymyxa NX20 is involved in the biocontrol of postharvest plant-pathogenic oomycete Phytophthora capsici

Phytophthora capsici is a destructive oomycete pathogen that mainly threatens solanaceous and cucurbitaceous vegetable crops, resulting in severe economic losses annually. Paenibacillus polymyxa, a typical biological control agent (BCA), has been widely used to control plant diseases due to its efficacy and environmentally friendly properties. However, the application of P. polymyxa to control pathogenic oomycete P. capsici during the postharvest period has not been reported. In this study, we found that P. polymyxa NX20 exhibited the best inhibitory effect on the mycelial growth of P. capsici among 160 cultivable isolates, and the lipopeptide fusaricidin was the main factor in its antagonistic action. Fusaricidin exhibited good inhibition activity against P. capsici with an EC50 value of 2.46 mg L−1. Both zoospore production and germination were suppressed by fusaricidin in a dose-dependent manner. According to the microscopy observation and cell membrane permeability assay, fusaricidin was proved to impaired the plasma membrane structure and led to cell death in P. capsici. Additionally, after exposure to fusaricidin, the reactive oxygen species accumulation was induced and DNA/protein synthesis was inhibited in P. capsici. RNA-Seq analysis revealed that fusaricidin treatment could potentially affect plasma membrane integrity, transmembrane transport, energy metabolism, and signal transduction in P. capsici. Furthermore, fusaricidin exhibited good control efficacy against P. capsici on watermelon, pepper, and cherry tomato fruit. Overall, these findings elucidated the anti-oomycete mechanism of fusaricidin and highlighted the potential of P. polymyxa strain NX20 on vegetable protection and preservation.

Suppression of Strawberry Anthracnose by Paenibacillus polymyxa TP3 In Situ and from a Distance.

Strawberry is a popular fruit with valuable nutrition and an attractive fragrance, but its production and propagation are limited by various diseases, including anthracnose and gray mold. For disease management, biological control measures are environmentally friendly and good alternatives to fungicides to avoid crop losses, reduce carbon emissions, and improve food safety. In this study, Paenibacillus polymyxa TP3, which originated from the strawberry phyllosphere, was shown to antagonize the anthracnose fungal pathogen Colletotrichum siamense and reduce leaf symptoms on strawberry plants. Several mass spectra corresponding to fusaricidin were detected in the confrontation assay of P. polymyxa TP3 and C. siamense by image mass spectrometry. The transcription of fusA and fusG in the fusaricidin biosynthesis gene cluster increased while P. polymyxa TP3 was cultured in the medium containing the culture filtrate of C. siamense, as detected by reverse-transcription polymerase chain reaction, indicating the involvement of fusaricidins in P. polymyxa TP3 antagonism against the anthracnose pathogen. Further disease control assays demonstrated the time frame and spatial mode of P. polymyxa TP3-induced systemic resistance of strawberry against C. siamense. The transcript level of the marker gene FaPDF1.2 of the jasmonic acid pathway increased in strawberry leaves after drenching treatment with P. polymyxa TP3, and the callose deposition was enhanced by further flg22 treatment. In addition, P. polymyxa TP3 treatments of the strawberry mother plants reduced C. siamense infection in the daughter plants, which would be a potent feature for the application of P. polymyxa TP3 in strawberry nurseries and fields to reduce the impact of diseases, especially anthracnose.

Carrot Discard as a Promising Feedstock to Produce 2,3-Butanediol by Fermentation with P. polymyxa DSM 365.

The valorization of fruit and vegetable residues (such as carrot discard) and their microbial conversion into 2,3-butanediol (BDO) can be considered as a very interesting way to reduce food waste and sustainably originate high value-added products. This work analyzes the valorization of carrot discard as feedstock for 2,3-butanediol (BDO) production by Paenibacillus polymyxa DSM 365. The influences of stirring and the presence of tryptone (nitrogen source) are studied. Furthermore, in order to evaluate the influence of the pre-culture medium (nitrogen source, nutrients, and pH) and the substrate, fermentation assays in simple and mixture semi-defined media (glucose, fructose, and/or galactose) were also carried out. As a result, 18.8 g/L BDO, with a BDO yield of 0.43 g/g (86% of its theoretical value), could be obtained from carrot discard enzymatic hydrolysate at 100 rpm, no tryptone, and pre-culture Häßler medium. No hydrothermal pre-treatment was necessary for BDO production from carrot discard, which increases the profitability of the process. Therefore, 18.8 g BDO, as well as 2.5 g ethanol and 2.1 g acetoin by-products, could be obtained from 100 g of carrot discard (dry matter).

Paenibacillus polymyxa YLC1: A promising antagonistic strain for biocontrol of Pseudomonas syringae pv. actinidiae, causing kiwifruit bacterial canker.

Kiwifruit bacterial canker (KBC) caused by Pseudomonas syringae pv. actinidiae (Psa) is the main limiting factor in the kiwifruit industry. This study aimed to identify bacterial strains with antagonistic activity against Psa, analyze antagonistically active substances, and provide a new basis for the biological control of KBC. A total of 142 microorganisms were isolated from the rhizosphere soil of asymptomatic kiwifruit. Among them, an antagonistic bacterial strain was identified as Paenibacillus polymyxa YLC1 by 16S rRNA sequencing. KBC control by strain YLC1 (85.4%) was comparable to copper hydroxide treatment (81.8%) under laboratory conditions and field testing. Active substances of strain YLC1 were identified by genetic sequence analysis using antiSMASH. The six biosynthetic active compound gene clusters that were identified as encoding ester peptide synthesis, such as polymyxins. An active fraction was purified and identified as polymyxin B1 using chromatography, hydrogen nuclear magnetic resonance (NMR), and liquid chromatography-mass spectrometry. In addition, polymyxin B1 was also found significantly to suppressed the expression of T3SS-related genes but did not affect the growth of Psa at low concentrations. In this study, a biocontrol strain P. polymyxa YLC1 obtained from kiwifruit rhizosphere soil exhibited excellent control effects on KBC in vitro and in field tests. Its active compound was identified as polymyxin B1, which inhibits a variety of pathogenic bacteria. We conclude that P. polymyxa YLC1 is a biocontrol strain with excellent prospects for development and application. This article is protected by copyright. All rights reserved.

Screening of Microorganisms Producing Polymer (PHB) from Dump Sites Soil in Ilorin Metropolis, Kwara State, Nigeria

This study was aimed at screening microorganisms isolated from dump sites for polymer production. Five samples of dump site soil were gathered from each of 10 distinct sites, totaling fifty samples, throughout the collection process. Microorganisms were isolated using the pour plate method. Bacteria isolates were identified using biochemical tests and molecular analysis using 16S rRNA gene primer while morphological characteristics are 18SrRNA gene primer were used to identify fungi isolate. Screening of the organisms for polymer production was done using Sudan Black Band Nile Blue A. The polymer extracted were analyzed using Fourier Transform Infrared Spectroscopy(FTIR) and Scanning Electron Microscope (SEM). Results revealed the presence of five fungi and seven bacterial species identified to be Aspergillus niger, Penicillium chrysogenum, Penicillium marneffei, Cladosporium tenuissimum and Rhizopus sp., while bacterial isolates were identified as Bacillus licheniformis, Bacillus cereus, Paenibacillus polymyxa, Bacillus megaterium, Bacillus mycoides, Bacillus subtillis and Enterobacter species. Only four bacterial isolates were positive for polymer production and molecularly identified as Bacillus subtilis strain AGB1 (OM273871), Bacillus megaterium strain AGB2 (OM216844), Paenibacillus polymyxa strain AGB3 (OM273889) and Bacillus licheniformis strain AGB4 (OP703543).The polymer has rough surfaces and crystalline in nature, while FTIR result indicated that the polymer had C=O carbonyl functional group and identified as polyhydrxybutyrate (PHB) polymer while SEM showed that it has crystalline surface. It can be concluded that bacterial isolates which were polymer producers can be utilized for large-scale production of polyhydroxybutyrate for industrial purposes

Safety Evaluation of Secretome Proteins from Paenibacillus polymyxa Kp10 and Lactococcus lactis Gh1 as the Potential Antimicrobial Therapeutic Agent

The secretome proteins of Paenibacillus polymyxa Kp10 and Lactococcus lactis Gh1 were previously found to have the potential for controlling the antibiotic-resistant pathogen. Therefore, their safety evaluation to ensure consumer health is deemed important. This study was to evaluate the toxicity effect of both secretome proteins in human cells against Medical Research Council cell strain 5 (MRC5). Then, their antibacterial activities were tested in human serum to assess the stability of both secretome proteins. The results showed no cytotoxic effects of either secretome protein when MRC5 cells were treated up to the determined concentrations. Therefore, no IC50 was determined. In addition, human serum did not affect the antibacterial activity of both secretome proteins against Methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-resistant Enterococcus (VRE). In conclusion, both secretome proteins are potentially safe for future development as a potential therapeutic agent.

Rheological characterization of artificial paenan compositions produced by Paenibacillus polymyxa DSM 365

Microbial exopolysaccharides offer a sustainable alternative to petroleum-based rheological modifiers. Recent studies revealed that the heteroexopolysaccharide produced by Paenibacillus polymyxa is composed of three distinct biopolymers, referred to as paenan I, II and III. Using CRISPR-Cas9 mediated knock-out variants of glycosyltransferases, defined polysaccharide compositions were produced and rheologically characterized in detail. The high viscosity and gel-like character of the wildtype polymer is proposed to originate from the non-covalent interaction between a pyruvate residue of paenan I and the glucuronic acid found in the backbone of paenan III. Paenan II conveys thermostable properties to the exopolysaccharide mixture. In contrast to the wildtype polymer mixture, knock-out variants demonstrated significantly altered rheological behavior. Using the rheological characterization performed in this study, tailor-made paenan variants and mixtures can be generated to be utilized in a wide range of applications including thickening agents, coatings, or high-value biomedical materials.

Development of a chemically defined medium for Paenibacillus polymyxa by parallel online monitoring of the respiration activity in microtiter plates

BackgroundOne critical parameter in microbial cultivations is the composition of the cultivation medium. Nowadays, the application of chemically defined media increases, due to a more defined and reproducible fermentation performance than in complex media. In order, to improve cost-effectiveness of fermentation processes using chemically defined media, the media should not contain nutrients in large excess. Additionally, to obtain high product yields, the nutrient concentrations should not be limiting. Therefore, efficient medium optimization techniques are required which adapt medium compositions to the specific nutrient requirements of microorganisms.ResultsSince most Paenibacillus cultivation protocols so far described in literature are based on complex ingredients, in this study, a chemically defined medium for an industrially relevant Paenibacillus polymyxa strain was developed. A recently reported method, which combines a systematic experimental procedure in combination with online monitoring of the respiration activity, was applied and extended to identify growth limitations for Paenibacillus polymyxa. All cultivations were performed in microtiter plates. By systematically increasing the concentrations of different nutrient groups, nicotinic acid was identified as a growth-limiting component. Additionally, an insufficient buffer capacity was observed. After optimizing the growth in the chemically defined medium, the medium components were systematically reduced to contain only nutrients relevant for growth. Vitamins were reduced to nicotinic acid and biotin, and amino acids to methionine, histidine, proline, arginine, and glutamate. Nucleobases/-sides could be completely left out of the medium. Finally, the cultivation in the reduced medium was reproduced in a laboratory fermenter.ConclusionIn this study, a reliable and time-efficient high-throughput methodology was extended to investigate limitations in chemically defined media. The interpretation of online measured respiration activities agreed well with the growth performance of samples measured in parallel via offline analyses. Furthermore, the cultivation in microtiter plates was validated in a laboratory fermenter. The results underline the benefits of online monitoring of the respiration activity already in the early stages of process development, to avoid limitations of medium components, oxygen limitation and pH inhibition during the scale-up.

Antibacterial activity of epsilon-poly-l-lysine produced by Stenotrophomonas maltophilia HS4 and Paenibacillus polymyxa HS5, alone and in combination with bacteriophages.

Over the past decades, antibiotic resistance has become a major clinical problem, and searching for new therapeutic strategies seems to be necessary. Using novel natural compounds, antimicrobial peptides, and bacteriophages is the most promising solution. In this study, various cationic metabolite-producer bacteria were isolated from different soil samples. Two isolates were identified as Stenotrophomonas maltophilia HS4 (accession number: MW791428) and Paenibacillus polymyxa HS5 (accession number: MW791430) based on biochemical characteristics and phylogenetic analysis using 16S rRNA gene sequences. The cationic compound in the fermentation broth was precipitated and purified with sodium tetraphenylborate salt. The purified cationic peptide was confirmed to be epsilon-poly-l-lysine by structural and molecular analysis using High-Performance Liquid Chromatography, Sodium dodecyl-sulfate-polyacrylamide gel electrophoresis, and Fourier-transform infrared spectroscopy. The antibacterial activity of epsilon-poly-l-lysine was evaluated against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29212, Serratia marcescens ATCC 13880, and Klebsiella pneumoniae ATCC 13883 by microdilution method. Furthermore, the antibacterial effects of purified epsilon-poly-l-lysine in combination with two long non-contractile tail bacteriophages against vancomycin-resistant Enterococcus faecalis and colistin-resistant Klebsiella pneumoniae were investigated. The results indicated great antibacterial activity of epsilon-poly-l-lysine which was produced by two novel bacteria. The epsilon-poly-l-lysine as a potent cationic antimicrobial peptide is demonstrated to possess great antimicrobial activity against pathogenic and also antibiotic-resistant bacteria.

Alpha-, gamma- and beta-proteobacteria detected in legume nodules in Latvia, using full-length 16S rRNA gene sequencing

ABSTRACT Rhizobia are soil bacteria that form nodules on legumes and fix atmospheric nitrogen, reducing the need for chemical fertilisers. In most studies rhizobia are described as alpha-proteobacteria and have been studied extensively for several decades. However, in recent years an increasing number of studies present beta- and gamma-proteobacteria strains as potential rhizobia-like bacteria. In this study we identify bacteria isolated from nodules of various legumes grown in Latvia, using a full-length 16S rRNA gene sequence, used for more precision, compared with a partial sequence of the gene. Bacterial strains in this study have been isolated from 1962–2019, part of which are rhizobia strains from a unique historical collection. This is the first time bacterial strains isolated from nodules in Latvian soils have been identified with molecular biology methods. A wide taxonomic diversity was detected – bacteria species from α-, β-, γ-proteobacteria classes and Paenibacillus polymyxa strains from the Bacilli class. P. polymyxa strains were detected only in the historical collection, while β- and γ-proteobacteria strains were obtained only from the newly isolated specimens, uncovering new potential strains for a commercial legume seed inoculum. Soil samples were collected, and phosphorus levels were determined. Several strains indicate phosphate solubilising properties.

Production of highly pure R,R-2,3-butanediol for biological plant growth promoting agent using carbon feeding control of Paenibacillus polymyxa MDBDO

BackgroundChemical fertilizers have greatly contributed to the development of agriculture, but alternative fertilizers are needed for the sustainable development of agriculture. 2,3-butanediol (2,3-BDO) is a promising biological plant growth promoter.ResultsIn this study, we attempted to develop an effective strategy for the biological production of highly pure R,R-2,3-butanediol (R,R-2,3-BDO) by Paenibacillus polymyxa fermentation. First, gamma-ray mutagenesis was performed to obtain P. polymyxa MDBDO, a strain that grew faster than the parent strain and had high production of R,R-2,3-BDO. The activities of R,R-2,3-butanediol dehydrogenase and diacetyl reductase of the mutant strain were increased by 33% and decreased by 60%, respectively. In addition, it was confirmed that the carbon source depletion of the fermentation broth affects the purity of R,R-2,3-BDO through batch fermentation. Fed-batch fermentation using controlled carbon feeding led to production of 77.3 g/L of R,R-2,3-BDO with high optical purity (> 99% of C4 products) at 48 h. Additionally, fed-batch culture using corn steep liquor as an alternative nitrogen source led to production of 70.3 g/L of R,R-2,3-BDO at 60 h. The fed-batch fermentation broth of P. polymyxa MDBDO, which contained highly pure R,R-2,3-BDO, significantly stimulated the growth of soybean and strawberry seedlings.ConclusionsThis study suggests that P. polymyxa MDBDO has potential for use in biological plant growth promoting agent applications. In addition, our fermentation strategy demonstrated that high-purity R,R-2,3-BDO can be produced at high concentrations using P. polymyxa.

Characterization of Antagonistic Bacteria Paenibacillus polymyxa ZYPP18 and the Effects on Plant Growth.

Paenibacillus polymyxa is a plant growth-promoting rhizobacteria (PGPR) that has significant biocontrol properties. Wheat sheath blight caused by Rhizoctonia cerealis is a significant soil-borne disease of wheat that causes significant losses in wheat production, and the biological control against the disease has received extensive attention. P. polymyxa ZYPP18 was identified using morphological and molecular characterization. An antagonistic activity experiment verified that ZYPP18 inhibits the growth of R. cerealis on artificial growth media. A detached leaf assay verified that ZYPP18 inhibits the expansion of wheat sheath blight on the detached leaf. ZYPP18 has been found to possess plant growth-promoting properties, as well as the ability to solubilize phosphate and generate indole-3-acetic acid. Results from hydroponic experiments showed that wheat seedlings treated with ZYPP18 grew faster. Additionally, pot experiments and field experiments demonstrated that ZYPP18 effectively controls the occurrence of wheat sheath blight. ZYPP18 reduced the incidence of wheat sheath blight in wheat seedlings by 37.37% and 37.90%, respectively. The control effect of ZYPP18 on wheat sheath blight was 56.30% and 65.57%, respectively. These findings provide evidence that P. polymyxa ZYPP18 is an effective biological factor that can control disease and promote plant growth.

Levan Production by Paenibacillus polymyxa Immobilized on Fe3O4@SiO2 Nanoparticles Using Molasses Medium with Emphasis on the Bioactivity

Levan Production by Paenibacillus polymyxa Immobilized on Fe3O4@SiO2 Nanoparticles Using Molasses Medium with Emphasis on the Bioactivity

Characterization of a newly discovered putative DNA replication initiator from Paenibacillus polymyxa phage phiBP

The bacteriophage phiBP contains a newly discovered putative replisome organizer, a helicase loader, and a beta clamp, which together may serve to replicate its DNA. Bioinformatics analysis of the phiBP replisome organizer sequence showed that it belongs to a recently identified family of putative initiator proteins. We prepared and isolated a wild type-like recombinant protein, gpRO-HC, and a mutant protein gpRO-HCK8A, containing a lysine to alanine substitution at position 8. gpRO-HC had low ATPase activity regardless of the presence of DNA, while the ATPase activity of the mutant was significantly higher. gpRO-HC bound to both single- and double-stranded DNA substrates. Different methods showed that gpRO-HC forms higher oligomers containing about 12 subunits. This work provides the first information about another group of phage initiator proteins, which trigger DNA replication in phages infecting low GC Gram-positive bacteria.

Identification of a New Pathogenic fungi Causing Sorghum Leaf Spot Disease and Its Management Using Natural Product and Microorganisms.

Sorghum bicolor is cultivated worldwide. Leaf spot of sorghum, which leads to leaf lesions and yield reduction, is a prevalent and serious disease in Guizhou Province, southwest China. In August 2021, new leaf spot symptoms were observed on sorghum leaves. In this study, traditional methods and modern molecular biology techniques were used to isolate and identify the pathogen. Sorghum inoculated with the isolate GY1021 resulted in reddish brown lesion that similar to symptoms observed in the field: the original isolate inoculated was reisolated and Koch's postulates were fulfilled. Based on morphological features and phylogenetic analysis of the internal transcribed spacer (ITS) combined sequence with β-tubulin (TUB2) and translation elongation factor 1-α (TEF-1α) genes, the isolate was identified as Fusarium thapsinum (Strain accession: GY 1021; GenBank Accession: ITS (ON882046), TEF-1α (OP096445), and β-TUB (OP096446)). Then, we studied the bioactivity of various natural products and microorganisms against F. thapsinum using the dual culture experiment. Carvacrol, 2-allylphenol, honokiol, and cinnamaldehyde showed excellent antifungal activity, with EC50 values of 24.19, 7.18, 46.18, and 52.81 µg/mL, respectively. The bioactivity of six antagonistic bacteria was measured using a dual culture experiment and the mycelial growth rate method. Paenibacillus polymyxa, Bacillus amyloliquefaciens and Bacillus velezensis displayed significant antifungal effects against F. thapsinum. This study provides a theoretical basis for the green control of leaf spot of sorghum.

Biosynthetic Gene Clusters in Sequenced Genomes of Four Contrasting Rhizobacteria in Phytopathogen Inhibition and Interaction with Capsicum annuum Roots.

Through screening of rhizobacteria, species that effectively suppress phytopathogens and/or promote plant growth are found. Genome sequencing is a crucial step in obtaining a complete characterization of microorganisms for biotechnological applications. This study aimed to sequence the genomes of four rhizobacteria that differ in their inhibition of four root pathogens and in their interaction with chili pepper roots to identify the species and analyze differences in the biosynthetic gene clusters (BGCs) for antibiotic metabolites and to determine possible phenotype-genotype correlations. Results from sequencing and genome alignment identified two bacteria as Paenibacillus polymyxa, one as Kocuria polaris, and one that was previously sequenced as Bacillus velezensis. Analysis with antiSMASH and PRISM tools showed that B. velezensis 2A-2B, the strain with the best performance of referred characteristics, had 13 BGCs, including those related to surfactin, fengycin, and macrolactin, not shared with the other bacteria, whereas P. polymyxa 2A-2A and 3A-25AI, with up to 31 BGCs, showed lower pathogen inhibition and plant hostility; K. polaris showed the least antifungal capacity. P. polymyxa and B. velezensis had the highest number of BGCs for nonribosomal peptides and polyketides. In conclusion, the 13 BGCs in the genome of B. velezensis 2A-2B that were not present in the other bacteria could explain its effective antifungal capacity and could also contribute to its friendly interaction with chili pepper roots. The high number of other BGCs for nonribosomal peptides and polyketide shared by the four bacteria contributed much less to phenotypic differences. IMPORTANCE To advance the characterization of a microorganism as a biocontrol agent against phytopathogens, it is highly recommended to analyze the potential of the profile of secondary metabolites as antibiotics that it produces to counteract pathogens. Some specific metabolites have positive impacts in plants. By analyzing sequenced genomes with bioinformatic tools, such as antiSMASH and PRISM, outstanding bacterial strains with high potential to inhibit phytopathogens and/or promote plant growth can be quickly selected to confirm and expand our knowledge of BGCs of great value in phytopathology.

Biocontrol potential of lipopeptides produced by Paenibacillus polymyxa AF01 against Neoscytalidium dimidiatum in pitaya.

Pitaya canker, caused by Neoscytalidium dimidiatum, is one of the most important fungal diseases that cause significant losses in production. To replace chemical pesticides, the use of biocontrol strains to manage plant diseases has been the focus of research. In this study, the bacterial strain AF01, identified as Paenibacillus polymyxa, exhibited significant antifungal effects against N. dimidiatum and four other pitaya fungal pathogens. The strain P. polymyxa AF01 produces 13 fusaricidins, which directly inhibit mycelial growth, spore germination and germ tube elongation by causing the membrane integrity and cell ultrastructure to incur irreversible damage. Pot experiment and yield test confirmed that AF01 provided preservative effects by reducing the disease index. In comparison to the untreated control groups, RNA-seq data showed that P. polymyxa AF01 selectively blocked some transcription and translation processes and inhibited RNA and DNA structural dynamics, energy production and conversion, and signal transduction, particularly cell wall biosynthesis, changes in membrane permeability, and impairment of protein biosynthesis. Thus, P. polymyxa AF01 could be potentially useful as a suitable biocontrol agent for pitaya canker.

Medium composition and aeration to high (R,R)-2,3-butanediol and acetoin production by Paenibacillus polymyxa in fed-batch mode.

Concerning the potential application of the optically active isomer (R,R)-2,3-butanediol, and its production by a non-pathogenic bacterium Paenibacillus polymyxa ATCC 842, the present study evaluated the use of a commercial crude yeast extract Nucel®, as an organic nitrogen and vitamin source, at different medium composition and two airflows (0.2 or 0.5 vvm). The medium formulated (M4) with crude yeast extract carried out with the airflow of 0.2 vvm (experiment R6) allowed for a reduction in the cultivation time and kept the dissolved oxygen values at low levels until the total glucose consumption. Thus, the experiment R6 led to a fermentation yield of 41% superior when compared to the standard medium (experiment R1), which was conducted at airflow of 0.5 vvm. The maximum specific growth rate at R6 (0.42h-1) was lower than R1 (0.60h-1), however, the final cell concentration was not affected. Moreover, this condition (medium formulated-M4 and low airflow-0.2 vvm) was a great alternative to produce (R,R)-2,3-BD at fed-batch mode, resulting in 30g.L-1 of the isomer at 24h of cultivation, representing the main product in the broth (77%) and with a fermentation yield of 80%. These results showed that both medium composition and oxygen supply have an important role to produce 2,3-BD by P. polymyxa.

Global gene-mining strategy for searching nonribosomal peptides as antimicrobial agents from microbial sources

Foodborne pathogenic microorganism contamination and the emergence of drug-resistant bacteria are serious threats to human public health, and cationic nonribosomal peptides (CNRPs) represent a potential solution to this threat. In this report, a global gene mining strategy was used to evaluate 6563 bacterial genomes, including Bacillus sp, Paenibacillus sp and Brevibacillus sp. Using antiSMASH with a Python script filter, we discovered that the Bacillus subtilis group, Paenibacillus polymyxa, Brevibacillus laterosporus and Brevibacillus brevis most likely produce a larger number and greater variety of CNRPs than other Bacilli bacteria. Amino acids lysine, ornithine, 2,4-diaminobutyric acid, leucine, valine, threonine and serine were incorporated in higher abundance (amino acid preference) into these antimicrobial NRPs. Furthermore, flat colony counting, acid-base titrations and Ubbelohde viscometry measurements indicated that brevilaterins from Brevibacillus laterosporus inhibited the growth of various microbes during the first four days and showed exceptional antimicrobial activity against various microbial contaminations in raw milk. Raw milk containing brevilaterins maintained its initial acidity and viscosity over two days. This study should facilitate the identification of new antimicrobial peptides derived from bacteria and their artificial design and modification, allowing those suitable microorganisms identified to be fully utilized in antimicrobial agent production and food industry applications.