Strain Paenibacillus Research Articles

Spore Heat Resistance and Growth Ability at Refrigeration Temperatures of Bacillus spp. and Paenibacillus spp.

In this study, spore heat resistance and growth ability at refrigeration temperatures of Bacillus spp. and Paenibacillus spp. were determined. The spore D90°C of 67.6% (23 of 34 strains) of Bacillus and 73.9% (17 of 23 strains) of Paenibacillus was less than 15 min. The growth abilities of both genera were equivalent at 10°C. However, 71.1% (32 of 45 strains) of Paenibacillus and only 6.3% (3 of 48 strains) of Bacillus cereus group could grow at 4°C. Eight B. cereus strains formed spores with higher heat resistance compared to the other Bacillus strains assessed; however, they did not grow at tempreratures below 10°C. Conversely, four Paenibacillus strains formed spores with heat resistance equivalent to that of the eight B. cereus strains and grew at 6°C or lower. In particular, Paenibacillus sp. JCM13343 formed the highest heat-resistant spores (D90°C = 136.1 min) and grew well at 4°C. These results indicate that Paenibacillus can grow in processed foods during refrigerated storage and has the potential to cause spoilage as well as Bacillus. Therefore, Paenibacillus should be considered as one of the targets for microbiological control in refrigerated processed foods.

Identification of Root-Associated Bacteria That Influence Plant Physiology, Increase Seed Germination, or Promote Growth of the Christmas Tree Species Abies nordmanniana.

Abies nordmanniana is used for Christmas tree production but poor seed germination and slow growth represent challenges for the growers. We addressed the plant growth promoting potential of root-associated bacteria isolated from A. nordmanniana. Laboratory screenings of a bacterial strain collection yielded several Bacillus and Paenibacillus strains that improved seed germination and produced indole-3-acetic acid. The impact of three of these strains on seed germination, plant growth and growth-related physiological parameters was then determined in greenhouse and field trials after seed inoculation, and their persistence was assessed by 16S rRNA gene-targeted bacterial community analysis. Two strains showed distinct and significant effects. Bacillus sp. s50 enhanced seed germination in the greenhouse but did not promote shoot or root growth. In accordance, this strain did not increase the level of soluble hexoses needed for plant growth but increased the level of storage carbohydrates. Moreover, strain s50 increased glutathione reductase and glutathione-S-transferase activities in the plant, which may indicate induction of systemic resistance during the early phase of plant development, as the strain showed poor persistence in the root samples (rhizosphere soil plus root tissue). Paenibacillus sp. s37 increased plant root growth, especially by inducing secondary root formation, under in greenhouse conditions, where it showed high persistence in the root samples. Under these conditions, it further it increased the level of soluble carbohydrates in shoots, and the levels of starch and non-structural carbohydrates in roots, stem and shoots. Moreover, it increased the chlorophyll level in the field trial. These findings indicate that this strain improves plant growth and vigor through effects on photosynthesis and plant carbohydrate reservoirs. The current results show that the two strains s37 and s50 could be considered for growth promotion programs of A. nordmanniana in greenhouse nurseries, and even under field conditions.

Comparative genomic analysis reveals metabolic diversity of different Paenibacillus groups.

The genus Paenibacillus was originally recognized based on the 16S rRNA gene phylogeny. Recently, a standardized bacterial taxonomy approach based on a genome phylogeny has substantially revised the classification of Paenibacillus, dividing it into 23 genera. However, the metabolic differences among these groups remain undescribed. Here, genomes of 41 Paenibacillus strains comprising 25 species were sequenced, and a comparative genomic analysis was performed considering these and 187 publicly available Paenibacillus genomes to understand their phylogeny and metabolic differences. Phylogenetic analysis indicated that Paenibacillus clustered into 10 subgroups. Core genome and pan-genome analyses revealed similar functional categories among the different Paenibacillus subgroups; however, each group tended to harbor specific gene families. A large proportion of genes in the subgroups A, E, and G are related to carbohydrate metabolism. Among them, genes related to the glycoside hydrolase family were most abundant. Metabolic reconstruction of the newly sequenced genomes showed that the Embden-Meyerhof-Parnas pathway, pentose phosphate pathway, and citric acid cycle are central pathways of carbohydrate metabolism in Paenibacillus. Further, the genomes of the subgroups A and G lack genes involved in glyoxylate cycle and D-galacturonate degradation, respectively. The current study revealed the metabolic diversity of Paenibacillus subgroups assigned based on a genomic phylogeny and could inform the taxonomy of Paenibacillus. KEY POINTS: • Paenibacillus clustered into 10 subgroups. • Genomic content variation and metabolic diversity in the subgroup A, E, and G were described. • Carbohydrate transport and metabolism is important for Paenibacillus survival.

Biodesulfurization of refractory sulfur compounds in petro-diesel by a novel hydrocarbon tolerable strain Paenibacillus glucanolyticus HN4.

One of the main precursors of air pollution and acid rains is the presence of the recalcitrant thiophenic compounds, for example dibenzothiophene (DBT) and its derivatives in transportation fuels. In an attempt to achieve the worldwide regulations of ultra-low sulfur transportation fuels without affecting its hydrocarbon skeleton, a biphasic medium containing 100 mg/L DBT dissolved in n-hexadecane (1/4 oil/water v/v) used for enrichment and isolation of selective biodesulfurizing bacterium from an oil-polluted sediment sample collected from Egyptian Red Sea shoreline. The isolated bacterium is facultative anaerobe, motile, spore-former, and mesophile. It is genetically identified as Paenibacillus glucanolyticus strain HN4 (NCBI Gene Bank Accession No. MT645230). HN4 desulfurized DBT as a model of the recalcitrant thiophenic compounds without affecting its hydrocarbon skeleton via the 4S-pathway producing 2-hydroxybiphenyl (2-HBP) as a dead end product. HN4 substantiated to be a hydrocarbon tolerant, biosurfactants(s) producer, and endorsed unique enzymatic system capable of desulfurizing broad range of thiophenic compounds and expressed an efficient desulfurization activity against the recalcitrant alkylated DBTs. As far our knowledge, it is the first reported BDS study using P. glucanolyticus. Statistical optimization based on One-Factor-At-A-Time (OFAT) technique and response surface methodology (RSM) applied for elucidation of mathematical model correlations describing and optimizing the effect of different physicochemical parameters on batch biphasic BDS process. That illustrated an approximate increase in BDS efficiency by 1.34 fold and recorded 94% sulfur removal in biphasic batch process at optimum operation conditions of 120 h, 0.14 wt% S-content model oil (DBT dissolved in n-hexadecane), 33.5 °C, pH7 and 1/1 oil/water phase ratio, and 147 rpm. Resting cells of HN4 in a biphasic reactor (1/1 v/v) decreased the sulfur content of a refractory thiophenic model oil (thiophene, benzothiophene, DBT, and alkylated DBT dissolved in n-hexadecane) from 0.14 to 0.027 wt%, and petro-diesel from 0.2 to 0.04 wt%, within 120 h, keeping the calorific value of the treated fuel intact. Consequently, that novel strain could be recommended as a promising candidate for BDS as complementary to hydrodesulfurization process in oil refinery.

Paenibacillus infection with frequent viral coinfection contributes to postinfectious hydrocephalus in Ugandan infants.

Postinfectious hydrocephalus (PIH), which often follows neonatal sepsis, is the most common cause of pediatric hydrocephalus worldwide, yet the microbial pathogens underlying this disease remain to be elucidated. Characterization of the microbial agents causing PIH would enable a shift from surgical palliation of cerebrospinal fluid (CSF) accumulation to prevention of the disease. Here, we examined blood and CSF samples collected from 100 consecutive infant cases of PIH and control cases comprising infants with non-postinfectious hydrocephalus in Uganda. Genomic sequencing of samples was undertaken to test for bacterial, fungal, and parasitic DNA; DNA and RNA sequencing was used to identify viruses; and bacterial culture recovery was used to identify potential causative organisms. We found that infection with the bacterium Paenibacillus, together with frequent cytomegalovirus (CMV) coinfection, was associated with PIH in our infant cohort. Assembly of the genome of a facultative anaerobic bacterial isolate recovered from cultures of CSF samples from PIH cases identified a strain of Paenibacillus thiaminolyticus This strain, designated Mbale, was lethal when injected into mice in contrast to the benign reference Paenibacillus strain. These findings show that an unbiased pan-microbial approach enabled characterization of Paenibacillus in CSF samples from PIH cases, and point toward a pathway of more optimal treatment and prevention for PIH and other proximate neonatal infections.

Draft Genome Sequences of Seven Strains of Paenibacillus spp. (Phylum Firmicutes) Inhabiting the Seeds of Cucumis melo L. (Cantaloupe) and Exhibiting Plant Probiotic Traits.

Here, we report the draft genome sequences of seven Paenibacillus sp. strains (EKM202P, EKM205P, EKM206P, EKM207P, EKM208P, EKM211P, and EKM212P) that were previously isolated from cultivated surface-sterilized seeds of Cucumis melo L. (cantaloupe). These candidate Paenibacillus plant probiotics displayed in vitro growth-promoting traits and suppressive activity against root-associated fungal/oomycete pathogens.

Plant-Growth-Promoting Bacteria (PGPB) against Insects and Other Agricultural Pests

The interest in using plant-growth-promoting bacteria (PGPB) as biopesticides is significantly growing as a result of the discovery of new properties of certain beneficial microbes in protecting agricultural crops. While several rhizobial species have been widely exploited for their ability to optimize plant use of environmental resources, now the focus is shifted to species that are additionally capable of improving plant health and conferring resistance to abiotic stress and deleterious biotic agents. In some cases, PGPB species may directly act against plant pathogens and parasites through a variety of mechanisms, including competition, protective biofilm formation, and the release of bioactive compounds. The use of this type of bacteria is in line with the principles of ecosustainability and integrated pest management, including the reduction of employing chemical pesticides. Several strains of Bacillus, Paenibacillus, Brevibacillus, Pseudomonas, Serratia, Burkholderia, and Streptomyces species have been the subject of specific studies in this direction and are under evaluation for further development for their use in biological control. Accordingly, specific case studies are presented and discussed.

Evaluation of cellulolytic exogenous enzyme-containing microbial inoculants as feed additives for ruminant rations composed of low-quality roughage

AbstractThe supplementation of ruminant diets with exogenous cellulolytic enzymes can improve their digestibility and feeding value. The objective of this study was to determine the effect of supplementing roughage (rice straw) and concentrate with inoculants containing four fungal strains (Pleurotus ostreatus, Phanerochaete chrysosporium, Trichoderma reesei and Trichoderma viride) and four bacterial strains (Paenibacillus polymyxa, Bacillus megaterium, Bacillus circulans and Bacillus subtilis), given separately or as a mixture, as a source of exogenous cellulolytic enzymes, on basic rumen parameters in vitro, including digestibility and methane production. A batch culture trial was used to select the best supplements, and a long-term rumen simulation technique (RUSITEC) was used to evaluate the effects of P. chrysosporium, B. subtilis, and a 1 : 1 mixture of these two on dietary component digestibility and fermentation parameters. In the batch culture evaluation, there were significant increases in the organic matter (OM) digestibility, the total gas production expressed as ml/g of dry matter, the OM, the neutral detergent fibre (NDF) and the acid detergent fibre (ADF) of the supplemented rations, as compared to the control, excluding the rations supplemented with T. viride and B. circulans. In the RUSITEC, the ration supplemented with mixed inoculants showed significantly higher digestibility of crude protein, ether extract, NDF and ADF than did the ration supplemented with the P. chrysosporium and B. subtilis inoculants. It can be concluded that the simultaneous use of fungal and bacterial exogenous cellulases on rice straw roughage improves its digestibility, without negative effects on other rumen parameters.

Paenibacillus alvei MP1 as a Producer of the Proteinaceous Compound with Activity against Important Human Pathogens, Including Staphylococcus aureus and Listeria monocytogenes.

An emerging need for new classes of antibiotics is, on the one hand, evident as antimicrobial resistance continues to rise. On the other hand, the awareness of the pros and cons of chemically synthesized compounds’ extensive use leads to a search for new metabolites in already known reservoirs. Previous research showed that Paenibacillus strain (P. alvei MP1) recovered from a buckwheat honey sample presented a wide spectrum of antimicrobial activity against both Gram-positive and Gram-negative pathogens. Recent investigation has confirmed that P. alvei MP1 (deposited at DDBJ/ENA/GenBank under the accession WSQB00000000) produces a proteinaceous, heat-stable compound(s) with the maximum antimicrobial production obtained after 18 h of P. alvei MP1 growth in LB medium at 37 °C with continuous shaking at 200 RPM. The highest activity was found in the 40% ammonium sulfate precipitate, with high activity also remaining in the 50% and 60% ammonium sulfate precipitates. Moderate to high antimicrobial activity that is insensitive to proteases or heat treatment, was confirmed against pathogenic bacteria that included L. monocytogenes FSL – X1-0001 (strain 10403S), S. aureus L1 – 0030 and E. coli O157: H7. Further studies, including de novo sequencing of peptides by mass spectrometry, are in progress.

Genome-based reclassification of Paenibacillus jamilae Aguilera et al. 2001 as a later heterotypic synonym of Paenibacillus polymyxa (Prazmowski 1880) Ash et al. 1994.

Paenibacillus is one of the genera that has high species diversity and Paenibacillus polymyxa, the type species of the genus, is mainly isolated from plant-associated environments. Among the plant-associated species, Paenibacillus jamilae B.3T (=CECT 5266T=DSM 13815T=KACC 10925T=KCTC 13919T) was proposed to be a novel species according to 16S rRNA gene similarity and DNA-DNA relatedness with related species, including Paenibacillus polymyxa. Nevertheless, in the description of Paenibacillus jamilae the used strain of Paenibacillus polymyxa was not the type strain of this species. In this work we found that the type strains of both species showed 16S rRNA gene similarity of 99.6 %. Therefore, in this study, we sequenced the genome of Paenibacillus jamilae KACC 10925T and compared it with those of the type strain of Paenibacillus polymyxa ATCC 842T and other phylogenetically related species. Genome relatedness value calculated by DNA-DNA hybridization between type strains of Paenibacillus polymyxa and Paenibacillus jamilae was 73.5 %, which is higher than the threshold value (70 %). For more objective and repeatable results of genome relatedness, we analysed an average nucleotide identity (ANI) between two strains. Our results showed that ANI value between the type strains of Paenibacillus jamilae and Paenibacillus polymyxa is 98.5 %, a phylogenetic distance also higher than the threshold values (95~96 %). These values were proposed by Yoon et al. (2017). In addition, their phylogenetic distance based on 92 bacterial core genes is highly close compared to other species. These mean that Paenibacillus jamilae and Paenibacillus polymyxa should be reclassified as a single species. Based on the results from genomic level comparison as well as reexamination results of physiological and chemotaxonomic features, we propose reclassification of Paenibacillus jamilae as a later heterotypic synonym of Paenibacillus polymyxa.

Groundwater inhabited Bacillus and Paenibacillus strains alleviate arsenic-induced phytotoxicity of rice plant

Arsenic contamination in agricultural soil now imposing a major threat to crop productivity and causing several hazardous health effects through percolation in food chain. Bioremediation, an efficient way of soil health restoration toward sustainability offered by some soil-borne microorganisms, has been reported. The present work deals with application of two potent arsenic-tolerant bacterial strains (Bacillus thuringiensis A01 and Paenibacillus glucanolyticus B05), obtained from natural sources in modulating overall growth and antioxidant defense against arsenic-treated rice plants. Between the two, former could reduce arsenic uptake up to 56% (roots) and 85% (shoots), and the preceding one up to 31% (roots) and 65% (shoots) in a hydroponic environment. Germination percentage was noted to be enhanced significantly (p ≤ 0.05). Expression of oxidative stress defensive enzymes such as superoxide dismutase, peroxidase and catalase have been augmented at seedling stages (21 days) toward detoxification of arsenic imposed excess ROS generation. Increment of leaf Thiobarbituric acid reactive substances due to arsenic exposure have been ameliorated by both the bacterial application. Phenolic and flavonoid mediated free radical scavenging ability of the test plants elevated significantly (p ≤ 0.05). The present work revealed that, selected bacterial strains can perform efficient bioremediation against arsenic pollutant rice cultivation.

Analogous wheat root rhizosphere microbial successions in field and greenhouse trials in the presence of biocontrol agents Paenibacillus peoriae SP9 and Streptomyces fulvissimus FU14.

Two Pythium‐infested soils were used to compare the wheat root and rhizosphere soil microbial communities from plants grown in the field or in greenhouse trials and their stability in the presence of biocontrol agents. Bacteria showed the highest diversity at early stages of wheat growth in both field and greenhouse trials, while fungal diversity increased later on, at 12 weeks of the crop cycle. The microbial communities were stable in roots and rhizosphere samples across both soil types used in this study. Such stability was also observed irrespective of the cultivation system (field or greenhouse) or addition of biocontrol coatings to wheat seeds to control Pythium disease (in this study soil infected with Pythium sp. clade F was tested). In greenhouse plant roots, Archaeorhizomyces, Debaryomyces, Delftia, and unclassified Pseudeurotiaceae were significantly reduced when compared to plant roots obtained from the field trials. Some operational taxonomic units (OTUs) represented genetic determinants clearly transmitted vertically by seed endophytes (specific OTUs were found in plant roots) and the plant microbiota was enriched over time by OTUs from the rhizosphere soil. This study provided key information regarding the microbial communities associated with wheat roots and rhizosphere soils at different stages of plant growth and the role that Paenibacillus and Streptomyces strains play as biocontrol agents in supporting plant growth in infested soils.

Beneficial Endophytic Bacteria-Serendipita indica Interaction for Crop Enhancement and Resistance to Phytopathogens.

Serendipita (=Piriformospora) indica is a fungal endophytic symbiont with the capabilities to enhance plant growth and confer resistance to different stresses. However, the application of this fungus in the field has led to inconsistent results, perhaps due to antagonism with other microbes. Here, we studied the impact of individual bacterial isolates from the endophytic bacterial community on the in vitro growth of S. indica. We further analyzed how combinations of bacteria and S. indica influence plant growth and protection against the phytopathogens Fusarium oxysporum and Rhizoctonia solani. Bacterial strains of the genera Bacillus, Enterobacter and Burkholderia negatively affected S. indica growth on plates, whereas Mycolicibacterium, Rhizobium, Paenibacillus strains and several other bacteria from different taxa stimulated fungal growth. To further explore the potential of bacteria positively interacting with S. indica, four of the most promising strains belonging to the genus Mycolicibacterium were selected for further experiments. Some dual inoculations of S. indica and Mycolicibacterium strains boosted the beneficial effects triggered by S. indica, further enhancing the growth of tomato plants, and alleviating the symptoms caused by the phytopathogens F. oxysporum and R. solani. However, some combinations of S. indica and bacteria were less effective than individual inoculations. By analyzing the genomes of the Mycolicibacterium strains, we revealed that these bacteria encode several genes predicted to be involved in the stimulation of S. indica growth, plant development and tolerance to abiotic and biotic stresses. Particularly, a high number of genes related to vitamin and nitrogen metabolism were detected. Taking into consideration multiple interactions on and inside plants, we showed in this study that some bacterial strains may induce beneficial effects on S. indica and could have an outstanding influence on the plant-fungus symbiosis.

Paenibacillus protaetiae sp. nov., isolated from gut of larva of Protaetia brevitarsis seulensis.

A Gram-stain-positive, rod-shaped, strictly aerobic, endospore-forming and motile bacterium with peritrichous flagella was isolated from a gut sample of the larva of Protaetia brevitarsis seulensis at the National Institute of Agricultural Sciences, Wanju-gun, Republic of Korea. Growth was observed at 15-50 °C (optimum, 28-37 °C), pH 6.0-8.0 (pH 7.0) and only without NaCl. 16S rRNA gene sequence comparisons indicated that strain FW100M-2T had the highest similarity to type strains of Paenibacillus thailandensis S3-4AT (96.8 %) and Paenibacillus agaridevorans DSM 1355T (96.3 %), and had sequence similarity values less than 96.0 % to all other taxa. The phylogenetic tree showed that strain FW100M-2T fell into the genus Paenibacillus, and formed a cluster with P. thailandensis S3-4AT independent from other Paenibacillus species. Antesio-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0 were detected as the major fatty acids. The only isoprenoid quinone was MK-7. Polar lipids of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, an unidentified aminophospholipid, two unidentified phospholipids and an unidentified lipid were present. The meso-diaminopimelic acid was present in the cell-wall peptidoglycan. The genomic DNA G+C content was 51.5 mol%. Hence, strain FW100M-2T represents a novel species of the genus Paenibacillus, for which the name Paenibacillus protaetiae sp. nov. is proposed, with FW100M-2T (=KACC 19327T=NBRC 113071T) as the type strain.

Whole genome mining reveals a diverse repertoire of lanthionine synthetases and lanthipeptides among the genus Paenibacillus.

Lanthionine or methyllanthionine-containing lanthipeptides belongs to ribosomally synthesized and post-translationally modified peptides (RiPPs) family. Recent revolution in sequencing has made available huge genome sequence dataset of micro-organisms. In this study, we performed genome mining of the complete and partial genome sequences of 479 bacteria of the genus Paenibacillus to determine the diversity and distribution of lanthipeptide gene clusters. All genome sequences were annotated by RAST and subsequently analysed by BAGEL and antiSMASH. A total of 221 lanthipeptide gene clusters were identified in 127 strains of the genus Paenibacillus. One hundred and fifty gene clusters were found associated with the production of class I lanthipeptides while 58 and 13 gene clusters were related to class II and class IV lanthipeptide production respectively. Frequency of strains whose genomes encode putative lanthipeptide precursors was 26·5%. The results of lanthionine synthetases analysis suggested that diversity of lanthipeptides is much more than anticipated, while lanthionine synthetases must have been co-evolved among various species of the genus Paenibacillus. This is the first report showing diversity and distribution of different classes of lanthipeptides among various species of the genus Paenibacillus. This study also reveals the novel lanthipeptide sequences which may be further developed as potential antimicrobials for therapeutic applications.

High Production of Cellulase by a Newly Isolated Strain Paenibacillus sp. IM7

With increasing fossil fuel price and environmental concern, alternative and renewable resources have become attractive. However, a large amount of the cheapest or negative-cost lignocellulosic biomass produced from agriculture and forest-based industries is the most abundant renewable resource to convert biofuels and value-added chemicals. The aim of this study was to produce carboxymethyl cellulase (CMCase), a key enzyme for utilizing lignocellulosic biomass produced in agriculture and forest-based industries to produce biofuels and value-added bioproduct. Five potential bacterial strains isolated from soil and rotted wood samples from Kingfisher Lake, Thunder Bay, Canada were screened for their cellulolytic activity using carboxymethyl cellulose as the sole carbon source. The most promising strain IM7 was identified as Paenibacillus sp. on the basis of 16S rRNA gene sequence analysis. In this study, the optimal conditions for high production of CMCase were defined in a completely aerobic process. The newly isolated Paenibacillus sp. IM7 strain showed the highest CMCase activity up to 17.7 ± 0.17 IU/mL using 1.5% yeast extract in the culture medium as a nitrogen source. Moreover, when the culture medium supplemented with 2% mannose as an inducer the CMCase activity was markedly boosted up to 24.59 ± 0.09 IU/mL. The optimum pH and temperature of the culture for CMCase production by the strain IM7 were 5.0 and 30 °C respectively, and the significant enzyme production was obtained at a wide temperature range of 25–55 °C. Therefore, this Paenibacillus IM7 strain could be a potential candidate for CMCase production in an industrial bioconversion process.

Isolation, identification and plant growth promotion ability of endophytic bacteria associated with lupine root nodule grown in Tunisian soil.

The present study aims to characterize nodule endophytic bacteria of spontaneous lupine plants regarding their diversity and their plant growth promoting (PGP) traits. The potential of PGPR inoculation was investigated to improve white lupine growth across controlled, semi-natural and field conditions. Lupinus luteus and Lupinus angustifolius nodules were shown inhabited by a large diversity of endophytes. Several endophytes harbor numerous plant growth promotion traits such as phosphates solubilization, siderophores production and 1-aminocyclopropane-1-carboxylate deaminase activity. In vivo analysis confirmed the plant growth promotion ability of two strains (Paenibacillus glycanilyticus LJ121 and Pseudomonas brenneri LJ215) in both sterilized and semi-natural conditions. Under field conditions, the co-inoculation of lupine by these strains increased shoot N content and grain yield by 25% and 36%, respectively. These two strains Paenibacillus glycanilyticus LJ121 and Pseudomonas brenneri LJ215 are effective plant growth-promoting bacteria and they may be used to develop an eco-friendly biofertilizer to boost white lupine productivity.

A novel intracellular dextranase derived from Paenibacillus sp. 598K with an ability to degrade cycloisomaltooligosaccharides.

Paenibacillus sp. 598K produces cycloisomaltooligosaccharides (CIs) in culture from dextran and starch. CIs are cyclic oligosaccharides consisting of seven or more α-(1 → 6)-linked-D-glucose residues. The extracellular enzyme CI glucanotransferase (PsCITase), which is the member of glycoside hydrolase family 66, catalyzes the final stage of CI production and produces mainly cycloisomaltoheptaose. We have discovered a novel intracellular CI-degrading dextranase (PsDEX598) from Paenibacillus sp. 598K. The 69.7-kDa recombinant PsDEX598 does not digest isomaltotetraose or shorter isomaltooligosaccharides, but digests longer ones of at least up to isomaltoheptaose. It also digests oligoCIs of cycloisomaltoheptaose, cycloisomaltooctaose, and cycloisomaltononaose better than it does with megaloCIs of cycloisomaltodecaose, cycloisomaltoundecaose, and cycloisomaltododecaose, as well as an α-(1 → 6)-D-glucan of dextran 40. PsDEX598 is produced intracellularly when culture medium is supplemented with cycloisomaltoheptaose or dextran, but not with isomaltooligosaccharides (a mixture of isomaltose, isomaltotriose, and panose), starch, or glucose. The whole genomic DNA sequence of the strain 598K implies that it harbors two genes for enzymes belonging to glycoside hydrolase family 66 (PsCITase and PsDEX598), and PsDEX598 is the only dextranase in the strain. PsDEX598 does not have any carbohydrate-binding modules (CBMs) and has a low similarity (< 30%) with other family 66 dextranases, and the catalytic amino acids of this enzyme are predicted to be Asp191, Asp303, and Glu368. The strain Paenibacillus sp. 598K appears to take up CI-7, so these findings indicate that this bacterium can degrade CIs using a dextranase within the cells and so utilize them as a carbon source for growth.

Screening, characterization and molecular-genetical identification of a new bacterial strain Paenibacillus species

Bacterial variant PS-K-17 was isolated from wheat grain contaminated by polysaccharide-producing microbiota for further characterization. It was found that the isolate grown on agar slants and in submerged culture on media with specific substrates synthesized beta-galactosidase, amylase, protease, pectinase, cellulase, beta-glucanase, lipase (esterase), alginase, extracellular polysaccharides, and pigments, probably carotenoids. Based on cultural-morphological and physiological-biochemical properties and phylogenetic analysis of nucleotide sequences of 16S rRNA gene (access code MF443394 in GenBank) the bacterial culture was identified as Paenibacillus species PS-K-17. The studied isolate forms one phylogenetic branch with type strains Paenibacillus nicotianae (98.3 %), Paenibacillus hordei (98.2 %), Paenibacillus kyungheensis (97.9 %), holding wherein a separate position. Strain Paenibacillus sp. PS-K-17 may find use in biotechnology as a producer of extracellular polysaccharides and enzymes splitting plant polymeric substances as well as a component of microbial consortium-ingredient of a new complex feed additive.

Influence of plant growth promoting rhizobacterial strains Paenibacillus sp. IITISM08, Bacillus sp. PRB77 and Bacillus sp. PRB101 using Helianthus annuus on degradation of endosulfan from contaminated soil

Endosulfan is a broad spectrum insecticide used in agriculture for protection of various food and non-food crops. It is persistent in nature and hence found in soil, air and water. The potential use of plants and microorganisms for the removal of endosulfan from soil was studied. Helianthus annuus plant was grown in soil spiked with 5, 10, 25 and 50 mg kg−1 concentrations of endosulfan and inoculated with plant growth promoting rhizobacterial strains Paenibacillus sp. IITISM08, Bacillus sp. PRB77 and Bacillus sp. PRB101 for 40, 80 and 120 days. Potential of plant for endosulfan uptake was evaluated by investigating the endosulfan levels in plant tissues (root and shoot). The results indicated that endosulfan accumulation followed the pattern of root > shoot as well as decrease in uptake of endosulfan in root and shoot of a plant grown in bacterial inoculated soil as compared to un-inoculated soil. Bacterial inoculation had a positive effect on endosulfan degradation. Maximum degradation of 92% at 5 mg kg−1 of endosulfan in soil was observed on inoculation with PRB101 after 120 days of inoculation. The results showed that plant growth promoting bacteria enhances plant biomass production. Lipid peroxidation was also estimated by determining the malondialdehyde (MDA) production, which is a biomarker of oxidative damage. Decrease in MDA formation by root and leaves of plants grown in the bacteria inoculated plant was also observed. The results suggested the effectiveness of plant growth promoting rhizobacteria to boost accumulation potential, biomass production and enhance remediation of endosulfan contaminated soil.