Strain Paenibacillus Research Articles

Endoglucanase improve the growth of homofermentative Lactobacillus spp. in ensilages

Endoglucanase, an important component of cellulases, is used as additives in ensiling of forage crops. However, its detailed role is unclear in ensilages. In the present study, two endoglucanases Cel5 and Cel9 produced by strain Paenibacillus panacisoli SDMCC050309, previously isolated from ensiled corn stover, were identified in the cultures by microcrystalline cellulose absorption coupled with zymogram analysis. After heterologously expressed in Escherichia coli DE3 and purified, these two proteins were biochemically characterized. Cel5 was 61 kDa and showed maximal activity at pH 7.0 and 45 °C, while the maximum activity was at pH 8.0 and 65 °C for Cel9 with 97 kDa in size. Both of them could degrade carboxymethyl cellulose into cellooligosaccharides, in which cellobiose and cellotriose could be used as substrates for the growth of homofermentative strains Lactobacillus plantarum CGMCC6888 and L. farciminis CCTCC AB2016237, but not for the heterofermentative strains L. brevis SDMCC050297 and L. parafarraginis SDMCC050300. Therefore, we concluded that the added endoglucanase contributed to enhance the growth of homofermentative lactic acid bacteria for high level of lactic acid production in ensilages.

Antifungal activity of various chitinolytic bacteria against Colletotrichum in pepper

Colletotrichum gleosporioides causes the anthracnose disease in plants including vegetables and fruits. The pathogenicity of the strains was confirmed by using pepper fruit inoculation assays. The chitinolytic bacterial strains Paenibacillus elgii HOA73, Lysobacter capsici HS124, Streptomyces griseus, Pseudomonas fluorescens, and Paenibacillus ehimensis MA2012 were evaluated against the phytopathogenic fungal strains. The bacteria significantly inhibited C. gleosporioides strain 40003, the inhibition ranging from 17% to 37%. Similarly, 5–41% inhibition of C. gleosporioides 40896 was noticed. Moreover, C. gleosporioides 40965 and 42113 were also inhibited. The n-butanol extracted crude compound of P. ehimensis MA2012 completely inhibited the spore germination of the phytopathogen. Hence the chitinolysis may be considered as an important trait for screening the biocontrol bacteria against anthracnose.

Isolation of diverse pyrene-degrading bacteria via introducing readily utilized phenanthrene

Bacteria able to degrade pyrene play a critical role in the biodegradation of high-molecular-weight polycyclic aromatic hydrocarbons (PAHs). However, the traditional isolation procedure only obtains strains related to the genus Mycobacterium. The aim of the present study was to develop a modified method to isolate taxonomically distinct pyrene-degrading strains. The results indicated that replacing pyrene with phenanthrene in the isolation step improved the isolation efficiency. Using the modified method, six PAH degraders belonging to the genera Bosea, Arthrobacter, Paenibacillus, Bacillus, and Rhodococcus were obtained. They were capable of effectively utilizing pyrene (∼100%) as their sole carbon source, and could co-metabolize the degradation of benzo [a]pyrene (26.9–71.5%). In contrast, a small amount of pyrene (5.6%) and benzo [a]pyrene (8.6%) were degraded by a phenanthrene-degrading Sphingobium sp. NS7 under the same conditions. The difference in PAHs degradation between agar plate culture and liquid culture may lead to the low isolation efficiency in the traditional procedure. Hereditary stability analysis showed that PAH degradation capability of the Bosea, Paenibacillus, and Rhodococcus strains were easily lost without PAH pressure, which may partly explain why those strains were difficult to obtain using the traditional method.

The Form of N Supply Determines Plant Growth Promotion by P-Solubilizing Microorganisms in Maize.

Phosphate-(P)-solubilizing microorganisms (PSM) are important drivers of P cycling in natural and agro-ecosystems. Their use as plant inoculants to improve P acquisition of crops has been investigated for decades. However, limited reproducibility of the expected effects, particularly under field conditions, remains a major challenge. This study demonstrates that the form of nitrogen fertilization has a significant impact on the performance of various fungal and bacterial PSM inoculants in maize grown on neutral to alkaline soils with limited P availability. Under these conditions, a high soil pH-buffering capacity frequently limits the efficiency of nutrient mobilization, mediated by plant roots and microorganisms via rhizosphere acidification. In a soil pH range between 7.0 and 8.0, nitrate fertilization promoting rhizosphere alkalinisation further aggravates this problem. Accordingly, in greenhouse experiments, six strains of Pseudomonas, Bacillus, Paenibacillus, Streptomyces, and Penicillium with proven P-solubilizing potential, completely failed to promote P acquisition in maize grown on a calcareous Loess sub-soil pH 7.6 with nitrate fertilization and rock phosphate (Rock-P) as a sparingly soluble P source. However, after replacement of nitrate fertilization by ammonium, stabilized with the nitrification inhibitor 3,4-dimethylpyrazole-phosphate (DMPP), five out of seven investigated PSM inoculants (comprising 12 fungal and bacterial PSM strains) exerted beneficial effects on plant growth and reached up to 88% of the shoot biomass production of a control supplied with soluble triple-superphosphate (TSP). Stabilized ammonium combined with PSM-inoculants improved P acquisition (Trichoderma harzianum T22, Pseudomonas sp. DMSZ 13134), while other strains particularly stimulated root growth (T. harzianum OMG16, Bacillus amyloliquefaciens FZB42), which promoted the acquisition also of other mineral nutrients, such as N, K, and Mn. A similar effect was recorded under field conditions on an alkaline clay-loam soil pH 8.6. The combination of stabilized ammonium with a range of consortium products based on T. harzianum OMG16, B. amyloliquefaciens, micronutrients, and humic acids completely compensated the effect of a TSP fertilization on field establishment, nutrient acquisition, and yield formation in maize, while non-stabilized urea-di-ammonium phosphate fertilization was largely ineffective. These findings suggest that the efficiency of PSM-plant interactions can be influenced by the form of N fertilization, offering promising perspectives for synergistic effects with stabilized ammonium fertilizers.

Efficient Reduction of Iron Oxides by Paenibacillus spp. Strains Isolated from Tropical Soils

The genus Paenibacillus was hardly described as a Fe(III)-reducing agent, only limited to reduce soluble forms or Fe inserted in poorly crystallized structures. In this study, three Paenibacillus strains capable of reducing manganese oxides in addition to iron oxides were isolated from Cameroonian and Brazilian soils. These strains reduced iron minerals from poorly crystallized 2-line ferrihydrite to well-crystallized Al-substituted and pure goethite with a significant production of soluble ferrous iron. These Paenibacillus strains, inhabitants from ferralitic temporarily waterlogged soils, could play an important role in the bioweathering of minerals and metal mobility in soils.

Antimicrobial activity and diversity of bacteria associated with Taiwanese marine sponge Theonella swinhoei

Marine sponges often rely on other epiphytes for protection from harmful predators. To understand the diversity and antimicrobial activity present among epiphytic bacteria isolated from marine sponge. We used both the 16S rRNA tag pyrosequencing method and the culture-based method to investigate the bacterial communities of Theonella swinhoei collected off the shore of southern Taiwan. Eight-hundred and eighteen operational taxonomic units (OTUs; 97% sequence similarity) were identified from 23,700 sponge-derived sequence tags. The bacteria associated with T. swinhoei were found to be highly diverse—as many as 12 different phyla of bacteria were identified. However, in terms of population evenness, the community was dominated by two phyla—Acidobacteria (71.54%) and Chloroflexi (19.60%). A total of 700 bacterial strains were isolated and cultured from samples of the sponge T. swinhoei. Within these culturable strains, only 12% were Actinomycetes. Despite the low percentage of Actinobacteria from the samples, among the 51 strains of culturable bacteria that showed high antimicrobial activity, a great majority (62%) were Actinomycetes (30 strains of Streptomyces and 1 strain each of Micromonospora and Brevibacterium). The remaining isolates that produced antimicrobial compounds were Gammaproteobacteria (10 strains of Pseudoalteromonas) and Firmicutes (8 and 1 strains of Bacillus and Paenibacillus, respectively). We speculated that many more Actinomycetes are yet to be isolated from T. swinhoei microbiota. Advanced techniques, such as high-throughput culture and culturome, should allow the isolation and purification of these medically important groups of bacteria from sponge.

Microbial Diversity in Decaying Oil Palm Empty Fruit Bunches (OPEFB) and Isolation of Lignin-degrading Bacteria from a Tropical Environment.

Oil palm empty fruit bunches (OPEFB) are the most abundant, inexpensive, and environmentally friendly lignocellulosic biomass in Malaysia. Investigations on the microbial diversity of decaying OPEFB may reveal microbes with complex enzymes that have the potential to enhance the conversion of lignocellulose into second-generation biofuels as well as the production of other value-added products. In the present study, fungal and bacterial diversities in decaying OPEFB were identified using Illumina MiSeq sequencing of the V3 region of the 16S rRNA gene and V4 region of the 18S rRNA gene. Fungal diversity in decaying OPEFB was dominated by the phylum Ascomycota (14.43%), while most of the bacterial sequences retrieved belonged to Proteobacteria (76.71%). Three bacterial strains isolated from decaying OPEFB, designated as S18, S20, and S36, appeared to grow with extracted OPEFB-lignin and Kraft lignin (KL) as the sole carbon source. 16S rRNA gene sequencing identified the 3 isolates as Paenibacillus sp.. The molecular weight distribution of KL before and after degradation showed significant depolymerization when treated with bacterial strains S18, S20, and S36. The presence of low-molecular-weight lignin-related compounds, such as vanillin and 2-methoxyphenol derivatives, which were detected by a GC-MS analysis, confirmed the KL-degrading activities of isolated Paenibacillus strains.

Surfactant-enhanced Bioremediation of n-Hexadecane-contaminated Soil Using Halo-tolerant Bacteria Paenibacillus glucanolyticus sp. Strain T7-AHV Isolated from Marine Environment

A halo-tolerant bacterial strain Paenibacillus glucanolyticus sp. strain T7-AHV isolated from marine environment was used for bioremediation of n-hexadecane-contaminated soil. Soil/water ratio, initial inoculums volume, surfactant addition, n-hexadecane concentration, and salinity were investigated. The possibility of biosurfactant production by isolated strain was also studied, and the results demonstrated that it was not a biosurfactant producer, based on measurement of the surface tension of culture broth. Both tween 80 and rhamnolipid enhanced the biodegradation of n-hexadecane significantly up to 44 and 46 %, respectively. A biodegradation rate of 39.7 % was observed at salinity level of up to 2 %, and the biodegradation efficiency decreased significantly at higher salinity concentrations. A natural hydrocarbon-contaminated soil sample with total petroleum hydrocarbon (TPH) concentration of 1437 mg kg–1 was subjected to bioremediation using the selected conditions of operational parameters, and a biodegradation rate of 22.1 % was obtained.

Identification of fusaricidins from the antifungal microbial strain Paenibacillus sp. MS2379 using ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry

Paenibacillus sp. MS2379 is a highly efficient microbial strain producing fusaricidins, a class of lipopeptides that have demonstrated strong antifungal activities against a broad array of fungal pathogens. An integrated approach combining chromatographic fractionation, UHPLC-QTOF-MS analysis, and NMR spectroscopic interpretation was employed to characterize antifungal metabolites produced by this microbial strain, resulting in the identification of 48 fusaricidins including 30 cyclic and 18 open-chain species. In this regard, UHPLC-QTOF-MS played a vital role in determining structures of 28 new fusaricidins through peptide fragment analysis. The structural determination of the new fusaricidins by the high-resolution mass spectrometry was validated by follow-up isolation and NMR spectroscopic analysis of representative compounds. It is worth noting that novel fusaricidins with amino acid residues of serine and γ-aminobutyric acid were identified, which is of great biosynthetic significance for this biologically important class of compounds. The present study again illustrates the power of UHPLC-QTOF-MS for structural identification of lipopeptides, and the structural diversity of the identified fusaricidins makes this microbial strain unique as a potential biocontrol agent.

Wild bees and their nests host Paenibacillus bacteria with functional potential of avail

BackgroundIn previous studies, the gram-positive firmicute genus Paenibacillus was found with significant abundances in nests of wild solitary bees. Paenibacillus larvae is well-known for beekeepers as a severe pathogen causing the fatal honey bee disease American foulbrood, and other members of the genus are either secondary invaders of European foulbrood or considered a threat to honey bees. We thus investigated whether Paenibacillus is a common bacterium associated with various wild bees and hence poses a latent threat to honey bees visiting the same flowers.ResultsWe collected 202 samples from 82 individuals or nests of 13 bee species at the same location and screened each for Paenibacillus using high-throughput sequencing-based 16S metabarcoding. We then isolated the identified strain Paenibacillus MBD-MB06 from a solitary bee nest and sequenced its genome. We did find conserved toxin genes and such encoding for chitin-binding proteins, yet none specifically related to foulbrood virulence or chitinases. Phylogenomic analysis revealed a closer relationship to strains of root-associated Paenibacillus rather than strains causing foulbrood or other accompanying diseases. We found anti-microbial evidence within the genome, confirmed by experimental bioassays with strong growth inhibition of selected fungi as well as gram-positive and gram-negative bacteria.ConclusionsThe isolated wild bee associate Paenibacillus MBD-MB06 is a common, but irregularly occurring part of wild bee microbiomes, present on adult body surfaces and guts and within nests especially in megachilids. It was phylogenetically and functionally distinct from harmful members causing honey bee colony diseases, although it shared few conserved proteins putatively toxic to insects that might indicate ancestral predisposition for the evolution of insect pathogens within the group. By contrast, our strain showed anti-microbial capabilities and the genome further indicates abilities for chitin-binding and biofilm-forming, suggesting it is likely a useful associate to avoid fungal penetration of the bee cuticula and a beneficial inhabitant of nests to repress fungal threats in humid and nutrient-rich environments of wild bee nests.

Screening of Xylanase and Glucose Isomerase Producing Bacteria Isolated from Hot Springs in Turkey

The aim of this study was screening of xylanase and glucose isomerase producing thermophilic bacteria isolated from some hot springs located to Aegean Region of Turkey. Total sixty eight thermophilic isolates (Anoxybacillus, Brevibacillus, Geobacillus, Aneurinibacillus, Thermus, Paenibacillus and Proteobacter) were collected previously from these fields and identified based on 16S rDNA gene sequences. The isolates were screened with plate assay for determining the xylanase and glucose isomerase production abilities seperately in order to find new strains for industrial processes. After an incubation period of two days for xylanase and 5-6 days for glucose isomerase at 50-60 °C, positive strains were determined. Enzyme producing strains were confirmed by spectrophotemetric measurements with crude enzyme extracts, birchwood xylan and glucose were used as substrates. Most of the strains (59 strains) were positive for xylan degradation while only sixteen of the strains had showed glucose isomerase activity. Fourteen of the strains have showed both xylanase and glucose isomerase activity. None of the Paenibacillus, Aneurinibacillus, and Proteobacter strains were glucose isomerase positive, although the glucose isomerase activity of Geobacillus strains were notably high. Both xylanase and glucose isomerase activities have observed at 50-60 °C which is suitable for biotechnological applications.

Screening and Taxonomic Characterization of Xylanase Bacterial Producers

A stepwise screening of bacterial xylanase producers isolated from forest soil in Moscow oblast has been performed, and the taxa of the microorganisms have been identified based on an analysis of the 16S RNA gene sequences. An approach to the selection of the most active producers is suggested, and this selection has been carried out, resulting in four producing strains. Interestingly, the species of two of the selected strains (Paenibacillus jamilae and P. brasilensis) are described as producers of xylanolytic enzymes for the first time, and the characteristics of those xylanases have not yet been studied. The new strains can serve as a source of genes for the construction of high-efficient xylanase producers.

Isolation and Characterisation of Endophytic Strain Paenibacillus polymyxa SR19 from Urtica dioica and the Study of Their Effect against Fusarium oxysporum f. sp Tomato

Isolation and Characterisation of Endophytic Strain Paenibacillus polymyxa SR19 from Urtica dioica and the Study of Their Effect against Fusarium oxysporum f. sp Tomato

BIOTRANSFORMATION OF GINSENOSIDE Rb1 BY BACTERIAL CRUDE ENZYME OF Paenibacillus spp. strain E3 ISOLATED FROM VIETNAMESE GINSENG SOIL

In ginseng, minor ginsenosides were more effective pharmacological properties than major ginsenosides. Therefore, finding bacteria that can convert major ginsenosides has been paying attention. Ginsenoside Rb1 is one of major ginsenosides of ginseng and its biotransformation produces pharmacologically active compounds such as compound K. In this study, the isolation of bacterial strains from Vietnamese ginseng cultivated soil was carried out with the objective of evaluating their hydrolytic capacity for use in biotransformation of ginsenosides Rb1. In the screening of β-glucosidase producing bacteria, seven isolates exhibited black color zones on R2A agar medium containing esculine. Among seven isolates, strain E3 showed the highest ability biotransformation of ginsenosides Rb1 in Luria-Bertani broth. Therefore, strain E3 was selected for further research. Biotransformation of Rb1 was observed by using thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) with ginsenoside standards for comparison. We determined the optimal conditions for biotransformation of ginsenoside Rb1 into the compound K of crude enzymes of strain E3 were at 30°C, pH 7,0 and 3 days. Ginsenoside Rb1 was converted into compound K via ginsenoside Rd and F2. The analyses of 16S rRNA gene and phylogenetic tree indicated that strain E3 was closely related to Paenibacillus terrigena with 99,4% identity and formed a discrete cluster with type strain Paenibacillus terrigena A35T with high bootstrap support (99%), supporting strain E3 belonging to the species Paenibacillus terrigena. Physiological characteristics also supported strain E3 belonging to the genus Peanibacillus. This is the first report of biotransformation of ginsenosides using bacterial strains isolated from Vietnamese ginseng cultivated soil in Vietnam. Based on our the obtained results, strain E3 could be applied for the preparation of ginsenoside compound K for use in the cosmetic and pharmaceutical industries.

An endophytic strain of genus Paenibacillus isolated from the fruits of Noni (Morinda citrifolia L.) has antagonistic activity against a Noni's pathogenic strain of genus Aspergillus

Endophytes are microbes capable of colonizing the tissues of healthy plants and subsequently establishing a harmonious relationship with their hosts. In this research, the endophytic strain Paenibacillus sp. NEB was isolated from fruits of healthy Noni (Morinda citrifolia L.). Strain NEB was identified as Paenibacillus polymyxa using MALDI-TOF Mass Spectrometry. Pathogenic fungal strain NP-1 was isolated from Noni fruits infected by smut, and was identified as Aspergillus aculeatus by polyphasic taxonomy basing on morphological identification, and ITS-5.8S rDNA and β-tubulin gene phylogenetic analyses. Through the antagonistic test against the pathogenic strain Aspergillus aculeatus NP-1, the results showed that strain NEB had a good antagonistic activity against smut pathogen of Noni. By sequencing with Illumina HiSeq 2000, the draft genome of Paenibacillus sp. NEB was acquired, and 3 CDSs for glucanases were annotated and potentially correlated to the antagonistic activity of this strain. Using realtime-PCR method with specific primers to amplify the biocontrol gene, β-1,3-1,4- glucanase gene (gluB), it was found in Paenibacillus polymyxa NEB. This study would provide a theoretical and microbial basis for the rationally developing and using Noni beneficial microbial inoculants against its pathogenic strain in the future.

Complete Genome Sequence of Industrial Biocontrol Strain Paenibacillus polymyxa HY96-2 and Further Analysis of Its Biocontrol Mechanism.

Paenibacillus polymyxa (formerly known as Bacillus polymyxa) has been extensively studied for agricultural applications as a plant-growth-promoting rhizobacterium and is also an important biocontrol agent. Our team has developed the P. polymyxa strain HY96-2 from the tomato rhizosphere as the first microbial biopesticide based on P. polymyxa for controlling plant diseases around the world, leading to the commercialization of this microbial biopesticide in China. However, further research is essential for understanding its precise biocontrol mechanisms. In this paper, we report the complete genome sequence of HY96-2 and the results of a comparative genomic analysis between different P. polymyxa strains. The complete genome size of HY96-2 was found to be 5.75 Mb and 5207 coding sequences were predicted. HY96-2 was compared with seven other P. polymyxa strains for which complete genome sequences have been published, using phylogenetic tree, pan-genome, and nucleic acid co-linearity analysis. In addition, the genes and gene clusters involved in biofilm formation, antibiotic synthesis, and systemic resistance inducer production were compared between strain HY96-2 and two other strains, namely, SC2 and E681. The results revealed that all three of the P. polymyxa strains have the ability to control plant diseases via the mechanisms of colonization (biofilm formation), antagonism (antibiotic production), and induced resistance (systemic resistance inducer production). However, the variation of the corresponding genes or gene clusters between the three strains may lead to different antimicrobial spectra and biocontrol efficacies. Two possible pathways of biofilm formation in P. polymyxa were reported for the first time after searching the KEGG database. This study provides a scientific basis for the further optimization of the field applications and quality standards of industrial microbial biopesticides based on HY96-2. It may also serve as a reference for studying the differences in antimicrobial spectra and biocontrol capability between different biocontrol agents.

Paenibacillus pabuli strain P7S promotes plant growth and induces anthocyanin accumulation in Arabidopsis thaliana

In this study, a novel plant growth-promoting rhizobacteria (PGPR), the bacterial strain Paenibacillus pabuli P7S (PP7S), showed promising plant growth-promoting effects. Furthermore, it induced anthocyanin accumulation in Arabidopsis. When co-cultivated with PP7S, there was a significant increase in anthocyanin content and biomass of Arabidopsis seedlings compared with those of the control. The quantitative reverse transcription-polymerase chain reaction analysis revealed higher expression of many key genes regulating anthocyanin and flavonoid biosynthesis pathways in PP7S-treated seedlings when compared with that of the control. Furthermore, higher expression of pathogen-related genes and microbe-associated molecular pattern genes was also observed in response to PP7S, indicating that the PGPR triggered the induced systemic response (ISR) in A. thaliana. These results suggest that PP7S promotes plant growth in A. thaliana and increases anthocyanin biosynthesis by triggering specific ISRs in plant.

Conversion of Squid Pens to Chitosanases and Proteases via Paenibacillus sp. TKU042.

Chitosanases and proteases have received much attention due to their wide range of applications. Four kinds of chitinous materials, squid pens, shrimp heads, demineralized shrimp shells and demineralized crab shells, were used as the sole carbon and nitrogen (C/N) source to produce chitosanases, proteases and α-glucosidase inhibitors (αGI) by four different strains of Paenibacillus. Chitosanase productivity was highest in the culture supernatants using squid pens as the sole C/N source. The maximum chitosanase activity of fermented squid pens (0.759 U/mL) was compared to that of fermented shrimp heads (0.397 U/mL), demineralized shrimp shells (0.201 U/mL) and demineralized crab shells (0.216 U/mL). A squid pen concentration of 0.5% was suitable for chitosanase, protease and αGI production via Paenibacillus sp. TKU042. Multi-purification, including ethanol precipitation and column chromatography of Macro-Prep High S as well as Macro-Prep DEAE (diethylaminoethyl), led to the isolation of Paenibacillus sp. TKU042 chitosanase and protease with molecular weights of 70 and 35 kDa, respectively. For comparison, 16 chitinolytic bacteria, including strains of Paenibacillus, were investigated for the production of chitinase, exochitinase, chitosanase, protease and αGI using two kinds of chitinous sources.

Purification and characterization of a highly viscous polysaccharide produced by Paenibacillus strain

The linear, 7.3 × 106 Da polysaccharide (PA) was purified from the extracellular polymeric product of Paenibacillus mucilaginosus WL412. Rheological results revealed that PA solution was typical shear-thinning fluid and it was more viscous than xanthan gum solution under the same conditions. Besides, PA formed a weak gel-like structure and the anti-shear, heat-resistant, and saline tolerant abilities were preferable to xanthan gum in the testing temperature range of 10–85 °C on the basis of thixotropy and oscillation analyses. Afterwards, the chemical structure of PA was elucidated by means of methylation-GC/MS, and 1D- and 2D-NMR spectra. PA consisted of three types of glycosides, namely mannoside, glucoside, and galactoside with molar ratio of 1.89:2.11:1.00. Besides, an acetyl group existed in every repeating unit. The possible structure of PA was identified as →4)α-Glc(1 → 2)α-Man(1 → 3)β-Glc(1 → 3)α-Man(6-Ac)(1 → 3)β-Gal(1→. These results indicate that PA is a potential additive for rheological modification, such as thickener and stabilizer.

Genome Mining of the Lipopeptide Biosynthesis of Paenibacillus polymyxa E681 in Combination with Mass Spectrometry: Discovery of the Lipoheptapeptide Paenilipoheptin.

Paenibacillus polymyxa strains are qualified for agro-biotechnological uses such as plant growth promotion and for biocontrol strategies against deleterious phytopathogenic competitors in the soil depending on their attractive arsenal of bioactive compounds. Moreover, they are potent producers of antibiotics for medical applications. To identify new products of such organisms, genome mining strategies in combination with mass spectrometry are the methods of choice. Herein, we performed such studies with the Paenibacillus strain E681. Bioinformatic evaluation of its genome sequence revealed four gene clusters A-D encoding nonribosomal peptide synthetases (NRPSs). Accordingly, four lipopeptide families were detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Clusters A and D codify the well known fusaricidins and polymyxins. A yet-unknown lipoheptapeptide was discovered and structurally characterized by de novo sequencing by using MALDI-LIFT-TOF/TOF MS. It was designated as paenilipoheptin. From structure predictions we infer that the production of this agent is encoded by gene cluster C. Gene cluster B encodes the synthesis of tridecaptins, a family of open-chain lipotridecapeptides. Strain E681 produces new subspecies of such compounds (tridecaptins E) showing variations both in their fatty-acid part as well as in their peptide part.