Paenibacillus Amylolyticus Research Articles

Effects of functional microbial agents on the microbial community and fertility of reclaimed soil in a coal mining area

Low soil fertility is the main factor limiting ecological restoration in coal mining reclamation areas. To improve the nutrient status and microbial community structure of reclaimed soil in coal mining areas, we tested a management strategy combining functional microbial agents, NPK, organic fertilizer, and straw to amend reclaimed soil. We selected corn as the crop for our greenhouse pot experiment, with a cultivation period of 80 days. Greenhouse pot trials were conducted with six treatments: no microbial agent (NMA), including CK (NPK), M (organic fertilizer and NPK), and S (straw and NPK); microbial agent (MA), including B (microbial and NPK), BM (microbial agent, organic fertilizer and NPK fertilizer), and BS (microbial agent, straw and NPK fertilizer). The results showed that the adding microbial agents changed the community structure of bacteria and fungi, and significantly changed the indicator microbial composition. The MA treatment group had an increase in five bacterial microbial network modules related to C and N functionalities such as Proteobacteria and Nitrospirae. In comparison to the B treatment, the combination of microbial agents with organic materials (BM and BS) significantly enhanced soil nutrient contents, including soil organic carbon (SOC), total nitrogen (TN). Therefore, the addition of functional microbial agents (Sphingomonas leidyi, Paenibacillus amylolyticus, and Paenibacillus mucilaginosus), especially in combination with organic materials, can significantly improve the contents of carbon, nitrogen and phosphorus nutrients, bacterial functional activity, and beneficial bacterial abundance in reclaimed soil, which is essential for the rapid improvement of reclaimed soil fertility in coal mining areas.

Produced by Paenibacillus amylolyticus to improve the sensory quality of the upper leaves in flue-cured tobacco

Produced by Paenibacillus amylolyticus to improve the sensory quality of the upper leaves in flue-cured tobacco

Synthetic Microbial Community Members Interact to Metabolize Caproic Acid to Inhibit Potato Dry Rot Disease.

The potato dry rot disease caused by Fusarium spp. seriously reduces potato yield and threatens human health. However, potential biocontrol agents cannot guarantee the stability and activity of biocontrol. Here, 18 synthetic microbial communities of different scales were constructed, and the synthetic microbial communities with the best biocontrol effect on potato dry rot disease were screened through in vitro and in vivo experiments. The results show that the synthetic community composed of Paenibacillus amylolyticus, Pseudomonas putida, Acinetobacter calcoaceticus, Serratia proteamaculans, Actinomycetia bacterium and Bacillus subtilis has the best biocontrol activity. Metabolomics results show that Serratia protoamaculans interacts with other member strains to produce caproic acid and reduce the disease index to 38.01%. Furthermore, the mycelial growth inhibition after treatment with caproic acid was 77.54%, and flow cytometry analysis showed that the living conidia rate after treatment with caproic acid was 11.2%. This study provides potential value for the application of synthetic microbial communities in potatoes, as well as the interaction mechanisms between member strains of synthetic microbial communities.

Interspecific interactions facilitate keystone species in a multispecies biofilm that promotes plant growth.

Microorganisms colonizing plant roots co-exist in complex, spatially structured multispecies biofilm communities. However, little is known about microbial interactions and the underlying spatial organization within biofilm communities established on plant roots. Here, a well-established four-species biofilm model (Stenotrophomonas rhizophila, Paenibacillus amylolyticus, Microbacterium oxydans, and Xanthomonas retroflexus, termed as SPMX) was applied to Arabidopsis roots to study the impact of multispecies biofilm on plant growth and the community spatial dynamics on the roots. SPMX co-culture notably promoted root development and plant biomass. Co-cultured SPMX increased root colonization and formed multispecies biofilms, structurally different from those formed by monocultures. By combining 16S rRNA gene amplicon sequencing and fluorescence in situ hybridization with confocal laser scanning microscopy, we found that the composition and spatial organization of the four-species biofilm significantly changed over time. Monoculture P. amylolyticus colonized plant roots poorly, but its population and root colonization were highly enhanced when residing in the four-species biofilm. Exclusion of P. amylolyticus from the community reduced overall biofilm production and root colonization of the three species, resulting in the loss of the plant growth-promoting effects. Combined with spatial analysis, this led to identification of P. amylolyticus as a keystone species. Our findings highlight that weak root colonizers may benefit from mutualistic interactions in complex communities and hereby become important keystone species impacting community spatial organization and function. This work expands the knowledge on spatial organization uncovering interspecific interactions in multispecies biofilm communities on plant roots, beneficial for harnessing microbial mutualism promoting plant growth.

Selection of aquatic microbiota exposed to the herbicides flufenacet and metazachlor.

Herbicides are important, ubiquitous environmental contaminants, but little is known about their interaction with bacterial aquatic communities. Here, we sampled a protected natural freshwater habitat and characterised its microbiome in interaction with herbicides. We evolved the freshwater microbiomes in a microcosm assay of exposure (28 days) to flufenacet and metazachlor at environmental concentrations of 0.5, 5 and 50 μg L-1 . Inhibitory effects of herbicides were exemplarily assessed in cultured bacteria from the same pond (Pseudomonas alcaligenes, Paenibacillus amylolyticus and Microbacterium hominis). Findings were compared to long-term concentrations as provided by local authorities. Here, environmental concentrations reached up to 11 μg L-1 (flufenacet) and 76 μg L-1 (metazachlor). Bacteria were inhibited at minimum inhibitory concentrations far above these values; however, concentrations of 50 μg L-1 of flufenacet resulted in measurable growth impairment. While most herbicide-exposed microcosm assays did not differ from controls, Acidobacteria were selected at high environmental concentrations of herbicides. Alpha-diversity (e.g., taxonomic richness on phylum level) was reduced when aquatic microbiomes were exposed to 50 μg metazachlor or flufenacet. One environmental strain of P. alcaligenes showed resistance to high concentrations of flufenacet (50 g L-1 ). In total, this study reveals that ecologic imbalance due to herbicide use significantly impacts aquatic microbiomes.

Whole-genome sequence of Paenibacillus amylolyticus strain W018, isolated from Triticum aestivum L. seeds, obtained using nanopore sequencing.

In this study, we performed nanopore sequencing of the genome of Paenibacillus amylolyticus strain W018, isolated from the seeds of winter wheat, cv. Bezostaya 100. The genome size is 7.07 Mb, with a GC content of 45.8%, and contains 8,190 genes.

Comparison of automatic methods MALDI-TOF, VITEK2 and manual methods for the identification of intestinal microbial communities on the example of samples from alpacas (Vicugna pacos).

Universally, in microbiological diagnostics the detection of live bacteria is essential. Rapid identification of pathogens enables appropriate remedial measures to be taken. The identification of many bacteria simultaneously facilitates the determination of the characteristics of the accompanying microbiota and/or the microbiological complexity of a given environment. The effectiveness of the VITEK2 Compact automated microbial identification system and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS), analytical profile index (API) and Remel RapID tests were compared in identification of bacteria isolated from the alpaca gastrointestinal tract. Most isolates were Gram-positive, such as Bacillus cereus, Bacillus flexus, Bacillus licheniformis, Bacillus pumilus and Bacillus subtilis; Enterococcus faecium, Enterococcus gallinarum, Enterococcus hirae and Enterococcus casseliflavus; Staphylococcus aureus, Staphylococcus equorum, Staphylococcus lentus, Staphylococcus pseudintermedius and Staphylococcus sciuri; Paenibacillus amylolyticus; Cellulosimicrobium cellulans; Leuconostoc mesenteroides; Clostridium perfringens; Corynebacterium stationis, Corynebacterium xerosis, and Corynebacterium diphtheriae (the last only isolated manually by API Coryne and the VITEK2 system and Corynebacteria (CBC) card). Corynebacterium diphtheriae was misidentified by MALDI-TOF MS as Candida lipolytica (currently Yarrowia lipolytica). Gram-positive and Gram-variable Micrococcus luteus were also isolated. Gram-negative Enterobacter cloacae, Enterobacter gergoviae, Enterobacter hormaechei and Enterobacter ludwigii; E. coli; Klebsiella pneumoniae subsp. pneumoniae; Citrobacter braakii and Citrobacter freundii; Serratia liquefaciens, Serratia odorifera and Serratia marcescens; Morganella morganii subsp. morganii; Providencia alcalifaciens; Pseudomonas aeruginosa; Stenotrophomonas maltophilia; Moraxella osloensis; and Ochrobactrum intermedium were also found. The yeasts Candida albicans, Candida haemulonii and Candida ciferrii were also present. MALDI-TOF MS enabled the identification of pathogens and opportunistic pathogens from the alpaca gut which may represent a high risk to human and animal health.

Application of starch degrading bacteria from tobacco leaves in improving the flavor of flue-cured tobacco.

Starch is an essential factor affecting the quality of flue-cured tobacco, and high starch content can affect the sensory quality and safety. Recently, the degradation of macromolecules in tobacco raw materials by using additional microorganisms to improve their intrinsic quality and safety has become a new research hotspot in the tobacco industry. However, the technical maturity and application scale are limited. Our study analyzed the correlation between microbial community composition and volatile components on the surface of tobacco leaves from 14 different grades in Fujian tobacco-producing areas. The PICRUSt software was utilized to predict the function of the microbial community present in tobacco leaves. Furthermore, dominant strains that produced amylase were screened out, and an enzyme solution was prepared to enhance the flue-cured tobacco flavor. Changes in the content of macromolecules and volatile components were determined, and sensory evaluations were conducted to assess the overall quality of the tobacco leaves. The results showed that the dominant bacterial genera on the surface of Fujian tobacco leaves were Variovorax, Sphingomonas, Bacillus, etc. Bacillus was positively correlated with various volatile components, which contributed to the sweet and aromatic flavors of Fujian flue-cured tobacco. The main genetic functions of Fujian flue-cured tobacco surface bacteria were carbohydrate metabolism and amino acid metabolism. After treating flue-cured tobacco with an enzyme preparation prepared by the fermentation of Paenibacillus amylolyticus A17 #, the content of starch, pectin, and cellulose in flue-cured tobacco decreased significantly compared with the control group. Meanwhile, the content of total soluble sugar and reducing sugar was significantly increased, and the volatile aroma components, such as 3-hydroxy--damascone, 2,3-dihydro-3,5-dihydroxy-6-methyl-4 H-Pyran-4-one, ethyl palmitate, ethyl linolenic acid, etc., were significantly increased. The aroma quality and quantity of flue-cured tobacco were enhanced, while impurities were reduced. The smoke characteristics were improved, with increased fineness, concentration, and moderate strength. The taste characteristics were also improved, with reduced irritation and a better aftertaste. In conclusion, Bacillus, as the dominant genus in the abundance of bacterial communities on tobacco surfaces in Fujian, had an essential impact on the flavor of tobacco leaves by participating in carbohydrate metabolism and finally forming the unique flavor style of flue-cured tobacco in Fujian tobacco-producing areas. Paenibacillus amylolyticus A17 #, a target strain with amylase-producing ability, was screened from the surface of Fujian flue-cured tobacco. The enzyme preparation, produced by the fermentation of Paenibacillus amylolyticus A17 #, was utilized to reduce the content of macromolecules, increase the content of water-soluble total sugar and reducing sugar, and produce a variety of crucial volatile aroma components, which had a significant improvement on the quality of tobacco leaves.

Inoculation with Potassium Solubilizing Bacteria and Its Effect on the Medicinal Characteristics of Paris polyphylla var. yunnanensis

Potassium (K) use efficiency in Paris polyphylla var. yunnanensis production is relatively low, and the excessive use of K fertilization has negative environmental impacts. Bacterial isolates can effectively alleviate this situation. The present work aimed to analyze the effects of different combinations of three potassium-solubilizing bacteria (KSB) (Bacillus thuringiensis, B. polymyxa, and Paenibacillus amylolyticus) on K in soil and P. polyphylla var. yunnanensis. The results showed that the contents of different forms of K were increased after the application of KSB. Compared with the control group, the maximum increases of slow-acting K, available K, quick-acting K, exchangeable K, and water-soluble K were 32.6% under inoculation with both P. amylolyticus and B. polymyxa, 73.5% with B. thuringiensis, 114.0% with B. thuringiensis, 83.2% with P. amylolyticus, and 210.0% with B. thuringiensis, respectively. This promoted the conversion of soil K to the form of K with high plant availability. Pseudo-protodiosgenin and diosgenin H contents were improved by KSB inoculations, which promoted medicinal quality of P. polyphylla var. yunnanensis. Correlation analysis showed that there were significantly positive correlations among the five forms of K in the soil in all experimental groups. In conclusion, the inoculation of KSB effectively improved the plant availability of soil K and medicinal quality of P. polyphylla var. yunnanensis, providing a path for sustainable production of P. polyphylla var. yunnanensis.

Geographically Disperse, Culturable Seed-Associated Microbiota in Forage Plants of Alfalfa (Medicago sativa L.) and Pitch Clover (Bituminaria bituminosa L.): Characterization of Beneficial Inherited Strains as Plant Stress-Tolerance Enhancers.

Agricultural production is being affected by increasingly harsh conditions caused by climate change. The vast majority of crops suffer growth and yield declines due to a lack of water or intense heat. Hence, commercial legume crops suffer intense losses of production (20-80%). This situation is even more noticeable in plants used as fodder for animals, such as alfalfa and pitch trefoil, since their productivity is linked not only to the number of seeds produced, but also to the vegetative growth of the plant itself. Thus, we decided to study the microbiota associated with their seeds in different locations on the Iberian Peninsula, with the aim of identifying culturable bacteria strains that have adapted to harsh environments and that can be used as biotreatments to improve plant growth and resistance to stress. As potentially inherited microbiota, they may also represent a treatment with medium- and long-term adaptative effects. Hence, isolated strains showed no clear relationship with their geographical sampling location, but had about 50% internal similarity with their model plants. Moreover, out of the 51 strains isolated, about 80% were capable of producing biofilms; around 50% produced mid/high concentrations of auxins and grew notably in ACC medium; only 15% were characterized as xerotolerant, while more than 75% were able to sporulate; and finally, 65% produced siderophores and more than 40% produced compounds to solubilize phosphates. Thus, Paenibacillus amylolyticus BB B2-A, Paenibacillus xylanexedens MS M1-C, Paenibacillus pabuli BB Oeiras A, Stenotrophomonas maltophilia MS M1-B and Enterobacter hormaechei BB B2-C strains were tested as plant bioinoculants in lentil plants (Lens culinaris Medik.), showing promising results as future treatments to improve plant growth under stressful conditions.

Metabolic Profiling of Interspecies Interactions During Sessile Bacterial Cultivation Reveals Growth and Sporulation Induction in Paenibacillus amylolyticus in Response to Xanthomonas retroflexus.

The toolbox available for microbiologists to study interspecies interactions is rapidly growing, and with continuously more advanced instruments, we are able to expand our knowledge on establishment and function of microbial communities. However, unravelling molecular interspecies interactions in complex biological systems remains a challenge, and interactions are therefore often studied in simplified communities. Here we perform an in-depth characterization of an observed interspecies interaction between two co-isolated bacteria, Xanthomonas retroflexus and Paenibacillus amylolyticus. Using microsensor measurements for mapping the chemical environment, we show how X. retroflexus promoted an alkalization of its local environment through degradation of amino acids and release of ammonia. When the two species were grown in proximity, the modified local environment induced a morphological change and growth of P. amylolyticus followed by sporulation. 2D spatial metabolomics enabled visualization and mapping of the degradation of oligopeptide structures by X. retroflexus and morphological changes of P. amylolyticus through e.g. the release of membrane-associated metabolites. Proteome analysis and microscopy were used to validate the shift from vegetative growth towards sporulation. In summary, we demonstrate how environmental profiling by combined application of microsensor, microscopy, metabolomics and proteomics approaches can reveal growth and sporulation promoting effects resulting from interspecies interactions.

Emergent bacterial community properties induce enhanced drought tolerance in Arabidopsis

Drought severely restricts plant production and global warming is further increasing drought stress for crops. Much information reveals the ability of individual microbes affecting plant stress tolerance. However, the effects of emergent bacterial community properties on plant drought tolerance remain largely unexplored. Here, we inoculated Arabidopsis plants in vivo with a four-species bacterial consortium (Stenotrophomonas rhizophila, Xanthomonas retroflexus, Microbacterium oxydans, and Paenibacillus amylolyticus, termed as SPMX), which is able to synergistically produce more biofilm biomass together than the sum of the four single-strain cultures, to investigate its effects on plant performance and rhizo-microbiota during drought. We found that SPMX remarkably improved Arabidopsis survival post 21-day drought whereas no drought-tolerant effect was observed when subjected to the individual strains, revealing emergent properties of the SPMX consortium as the underlying cause of the induced drought tolerance. The enhanced drought tolerance was associated with sustained chlorophyll content and endogenous abscisic acid (ABA) signaling. Furthermore, our data showed that the addition of SPMX helped to stabilize the diversity and structure of root-associated microbiomes, which potentially benefits plant health under drought. These SPMX-induced changes jointly confer an increased drought tolerance to plants. Our work may inform future efforts to engineer the emergent bacterial community properties to improve plant tolerance to drought.

Identification of Canola Roots Endophytic Bacteria and Analysis of Their Potential as Biofertilizers for Canola Crops with Special Emphasis on Sporulating Bacteria

Canola (Brassica napus L. var. oleracea) is the third most common oil-producing crop worldwide after palm and soybean. Canola cultivation requires the use of chemical fertilizers, but the amount required can be reduced by applying plant growth-promoting bacteria (PGPB). Among PGPB, endophytic bacteria have certain advantages as biofertilizers, but canola endophytic bacteria have rarely been studied. In this work, we identified a collection of bacterial endophytes isolated from canola roots using MALDI-TOF MS, a technique that is still rarely used for the identification of such bacteria, and rrs gene sequencing, a methodology that is commonly used to identify canola endophytes. The results demonstrated that some bacterial isolates from canola roots belonged to the genera Bacillus, Neobacillus, Peribacillus (Pe.), and Terribacillus, but most isolates belonged to the genera Paenibacillus (P.) and Pseudomonas (Ps.). Inoculation of these isolates indicated that several of them could efficiently promote canola seedling growth in hydroponic conditions. These results were then confirmed in a microcosm experiment using agricultural soil, which demonstrated that several isolates of Pseudomonas thivervalensis, Paenibacillus amylolyticus, Paenibacillus polymyxa, Paenibacillus sp. (Paenibacillus glucanolyticus/Paenibacillus lautus group), and Peribacillus simplex (previously Bacillus simplex) could efficiently promote canola shoot growth under greenhouse conditions. Among them, the isolates of Paenibacillus and Peribacillus were the most promising biofertilizers for canola crops as they are sporulated rods, which is an advantageous trait when formulating biofertilizers.

Diversity of aerobic spore-forming bacteria isolated from fresh bee pollen intended for human consumption in Argentina

Bee pollen is the result of the agglutination of pollen grains collected from flowers and mixed with nectar and salivary secretions by honey bees. Bee pollen is a natural product exposed to environmental conditions and also provides a unique microhabitat for yeasts and bacterial communities. We analyzed 30 fresh bee pollen samples obtained from the main producing areas of Argentina to identify aerobic-spore-forming bacteria. We obtained 73 isolates belonging to 16 different species through isolation on selective and differential media, morphological and biochemical tests, and PCR and RFLP analysis of genes encoding 16S rRNA. Our data revealed that Bacillus cereus sensu stricto was the most predominant species (50%), followed by Bacillus megaterium (40%) and Bacillus subtilis (40%), respectively. In a minor proportion, Paenibacillus polymyxa (20%), Paenibacillus larvae (17%), Bacillus pumilus (13%), Bacillus licheniformis (13%), Bacillus amyloliquefaciens (10%), Lysinibacillus sphaericus (7%), Bacillus coagulans (7%), Rummelliibacillus stabekisii (7%), Bacillus thuringiensis (7%), Bacillus clausii (3%), Paenibacillus alvei (3%), Bacillus simplex (3%), and Paenibacillus amylolyticus (3%) were also found. Our results showed that Argentinean bee pollen could transmit honey bee diseases due to the presence of viable spores of P. larvae and also spores of toxicogenic B. cereus s.s. and B. megaterium strains.

Evaluation of the biological flotation reagent obtained from Paenibacillus amylolyticus in magnetite and phlogopite flotation system

Bio-flotation is a method used biological organisms to replace harmful chemicals for processing ores, and realized avoiding environmental and safety issues. In this study, the flotation separation of magnetite and phlogopite was examined using biological reagent obtained from Paenibacillus amylolyticus. Micro-flotation experiments were performed by two flotation modes: bacteria pretreatment mineral (Ⅰ) and using the suspension of mineral and bacterial culture at different growth phase (Ⅱ). The test results of flotation mode (Ⅰ) showed that biological reagent exhibited high effectiveness in separation of magnetite and phlogopite. On the other hand, flotation mode (Ⅱ) obtained the best result regarding the iron grade of concentrate 69.56 % by using the bacteria culture growth phases of 8 d, being highly competitive as compared to mode (Ⅰ). For both flotation mode, flotation separation was driven by the selective adsorption of bacterial cells and metabolic products (including proteins and polysaccharides) mechanism. The results from analysis of SEM, Zeta potential measurements and the adsorption behavior of bacteria metabolites on mineral surfaces clearly showed that bacterial cells exhibited higher adsorption density on the magnetite surface than phlogopite in flotation mode (Ⅰ), and extracellular polysaccharide illustrated a higher adsorption density on magnetite, making it more hydrophilic in flotation mode (Ⅱ).

Effect of some rhizosphere bacteria on root-knot nematodes

BackgroundRoot-knot nematodes are among the world’s most damaging endoparasitic sedentary nematodes, especially, Meloidogyne incognita that infects a wide range of plant hosts. The activity of different antagonistic bacteria was studied for the low-cost and eco-friendly management of M. incognita on eggplant.Main bodyTwenty-five isolates were isolated from rhizosphere soils infected with nematodes. Of these, 6 isolates displayed the highest activity, demonstrating 100% mortality of J2 nematodes under laboratory conditions. Partial sequencing of 16S rRNA gene and phylogenetic analysis was used to identify the selected isolates and they were found to be Paenibacillus amylolyticus, Brevibacillus agri, Gluconobacter frateurii, Beijerinckia mobilis, Achromobacter aloeverae, and Pseudomonas stutzeri. The abilities of the selected isolates to produce hydrogen cyanide, siderophores, chitinase, protease, indole acetic acid, and to dissolve phosphorus were also detected.ConclusionThe results of the greenhouse experiment indicated that all the tested bacteria had a greatly significant effectiveness for suppressing root-knot nematode M. incognita. Application of all the rhizosphere bacteria and their combinations reduced the number of galls, number of juveniles, egg-masses, eggs, females, and total final population. All bio-agent treatments succeeded in improving the plant growth parameters and increased the microbial density in eggplant rhizosphere.

Standardisation and categorization of indigenous microorganisms (IMOs) for inoculated deep litter piggery in India

The present experiment was conducted on standardisation and categorization of Indigenous Microorganisms (IMOs) in India for its future application as inoculum in inoculated deep litter housing of pigs. The cultivation of IMOs was accomplished in four steps, which involved use of half cooked rice, sugar sources, rice bran and soil at 1st, 2nd, 3rd and 4th steps, respectively. The cultivated IMOs at the end of each step from 1st to 4th were named accordingly as IMO-1, IMO-2, IMO-3 and IMO-4. The cultivation of IMOs was done in three groups based on the major sources of energy at 2nd step as control (brown sugar), treatment 1 (Jaggery) and treatment 2 (Molasses). The IMO-1 was obtained after 7 days which was confirmed based on the appearance of white coloured fungal mycelium in all the groups. The IMO-4 was considered as the final product of cultivation process which was confirmed by the presence of fungal mycelium interwoven in the soil. IMO-4 stage was further categorised in different microbial groups based on laboratory examination and only two categories of microbes were witnessed namely bacteria and fungi, none of yeast were found in those inoculums. Out of four types of bacterial colonies, IMB-3 confirmed the presence of Paenibacillus amylolyticus and IMB-4 as Enterococcus casseliflavus. The standardisation of IMOs as inoculum for deep litter housing was performed first time in India.

Promoción del crecimiento de Agave potatorum Zucc. por bacterias fijadoras de nitrógeno de vida libre

Las bacterias f ijadoras de nitrógeno de vida libre (BFNVL) pueden ser una importante alternativa para reemplazar los fertilizantes nitrogenados en la agricultura. Agave potatorum Zucc, coloquialmente conocido como maguey tobalá, es una especie silvestre de la cual se obtiene un mezcal muy demandado debido a su alta calidad. Al ser una especie silvestre, no existe mucha información referente a su manejo agronómico. En este estudio se evaluó el efecto de BFNVL en el crecimiento y contenido de sólidos solubles totales (SST) en plantas de A. potatorum bajo condiciones semi-controladas. Bajo un diseño en bloques completamente al azar se evaluaron tres BFNVL (1) Burkholderia cepacia, (2) Flavobacterium sp., (3) Paenibacillus amylolyticus y un control (sin BFNVL). En total se tuvieron 4 bloques con 15 plantas de agave por bloque, dentro de cada bloque a cada planta de agave se le aplicó al azar una BFNVL diferente. Las variables de crecimiento vegetal evaluadas después de 48 semanas fueron: altura de la planta (AP), diámetro de roseta (DRO), diámetro del tallo (DT), número de hojas desplegadas (NHD), volumen radicular (VR), densidad de raíz (DR), biomasa seca del tallo (BST), biomasa total (BT), área foliar (AF) y, SST en el tallo (°Bx). El análisis de varianza y la prueba de comparación múltiple de medias (Tukey, P ≤ 0.05) revelaron que con respecto al control, B. cepacia incrementó 322.2% el VR, 42.6% el NHD y 72.9% los SST. P. amylolyticus incrementó 317.1% la BST. B. cepacia, Flavobacterium sp. y P. amylolyticus incrementaron aproximadamente 50.3% el DT, 48.6% el DRO, 127.2% el AF y 51.8% la AP. Flavobacterium sp. incrementó 164.8% la BT. Estos resultados sugieren que las BFNVL promueven el crecimiento de A. potatorum, por lo que pueden ser una tecnología ambientalmente amigable y económica para la producción de este agave.

The Homogalacturonan Deconstruction System of Paenibacillus amylolyticus 27C64 Requires No Extracellular Pectin Methylesterase and Has Significant Industrial Potential.

Paenibacillus amylolyticus 27C64, a Gram-positive bacterium with diverse plant cell wall polysaccharide deconstruction capabilities, was isolated previously from an insect hindgut. Previous work suggested that this organism's pectin deconstruction system differs from known systems in that its sole pectin methylesterase is cytoplasmic, not extracellular. In this work, we have characterized the specific roles of key extracellular pectinases involved in homogalacturonan deconstruction, including four pectate lyases and one pectin lyase. We show that one newly characterized pectate lyase, PelC, has a novel substrate specificity, with a lower Km for highly methylated pectins than for polygalacturonic acid. PelC works synergistically with PelB, a high-turnover exo-pectate lyase that releases Δ4,5-unsaturated trigalacturonate as its major product. It is likely that PelC frees internal stretches of demethylated homogalacturonan which PelB can degrade. We also show that the sole pectin lyase has a high kcat value and rapidly depolymerizes methylated substrates. Three cytoplasmic GH105 hydrolases were screened for the ability to remove terminal unsaturated galacturonic acid residues from oligogalacturonide products produced by the action of extracellular lyases, and we found that two are active on demethylated oligogalacturonides. This work confirms that efficient homogalacturonan deconstruction in P. amylolyticus 27C65 does not require extracellular pectin methylesterase activity. Three of the extracellular lyases studied in this work are also thermostable, function well over a broad pH range, and have significant industrial potential.IMPORTANCE Pectin is an important structural polysaccharide found in most plant cell walls. In the environment, pectin degradation is part of the decomposition process that turns over dead plant material and is important to organisms that feed on plants. Industrially, pectinases are used to improve the quality of fruit juices and can also be used to process coffee cherries or tea leaves. These enzymes may also prove useful in reducing the environmental impact of paper and cotton manufacturing. This work is significant because it focuses on a Gram-positive bacterium that is evolutionarily distinct from other well-studied pectin-degrading organisms and differs from known systems in key ways. Most importantly, a simplified extracellular deconstruction process in this organism is able to break down pectins without first removing the methyl groups that inhibit other systems. Moreover, some of the enzymes described here have the potential to improve industrial processes that rely on pectin deconstruction.

Effects of Lactobacillus hilgardii 60TS-2, with or without homofermentative Lactobacillus plantarum B90, on the aerobic stability, fermentation quality and microbial community dynamics in sugarcane top silage

This study investigated the effects of Lactobacillus hilgardii (LH), alone or in combination with Lactobacillus plantarum (LP), on the aerobic stability, fermentation quality and dynamics of the bacterial and fungal communities of sugarcane top silage. Results demonstrated that LH and LHLP (LH combined with LP) improved the aerobic stability of sugarcane top silages. As the exposure time increased, the pH values and the contents of lactic acid, acetic acid, as well as propionic acid remained stable in silage treated with LH and LHLP. The abundance of L. hilgardii was enriched and the undesirable microorganisms, such as Acetobacter pasteurianus, Paenibacillus amylolyticus and yeasts like Kazachstania humilis, were suppressed in silages treated with LH and LHLP. In conclusion, LH-treated silage, whether with LP or not, positively impacted the fungal and bacterial microbes. This improved the quality of fermentation, the aerobic stability, and reduced aerobic spoilage in sugarcane top silage.