Bacillus Toyonensis Research Articles

Reduction of Cr(VI) by Bacillus toyonensis LBA36 and its effect on radish seedlings under Cr(VI) stress.

Chromium, being among the most toxic heavy metals, continues to demand immediate attention in the remediation of Cr-contaminated environments. In this study, a strain of LBA36 (Bacillus toyonensis) was isolated from heavy metal contaminated soil in Luanchuan County, Luoyang City, China. The reduction and adsorption rates of LBA36 in 30 mg·L-1 Cr-containing medium were 97.95% and 8.8%, respectively. The reduction mechanism was confirmed by Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy (XPS). Cr(VI) reduction by this strain predominantly occurred outside the cell, with hydroxyl, amide, carboxyl, C-N group, carbonyl, and sulfur carbonyl as the main reaction sites. XPS analysis revealed the presence of Cr2p1/2 and Cr2p3/2. Furthermore, the hydroponic experiment showed that the fresh weight and plant height of radish seedlings increased by 87.87% and 37.07%, respectively, after inoculation with LBA36 strain under 7 mg·L-1 Cr(VI) stress. The levels of chlorophyll, total protein, malondialdehyde, superoxide dismutase and catalase were also affected to different degrees. In conclusion, this study demonstrated the potential of microbial and phytoremediation in the treatment of heavy metal toxicity, and laid the foundation for the development of effective bioremediation methods for Cr(VI) pollution.

A study of bacteria producing carbonic anhydrase enzyme for CaCO3 precipitation and soil biocementation

We study the carbonic anhydrase (CA) pathway using autochthonous CA-producing bacteria as a means of inducing calcite precipitation, which acts as a biocement to improve the engineering soil properties. Forty different microbial strains producing CA were isolated from the foundation soil of a railway embankment in Prickwillow, UK. Three of the best CA-producing strains were selected and identified by DNA sequencing as Bacillus licheniformis, Bacillus toyonensis and Bacillus pumilus with CA activity values respectively of 1.79 U/ml, 1.42 U/ml and 1.55 U/ml. To optimise the treatments, we investigated the effect of pH, temperature, zinc co-factor and cementation solution molarity on the growth and CA activity and bioprecipitates, with CO2 added in the form of bicarbonate. Scanning electron microscope (SEM) analysis of the bioprecipitates showed that these had characteristic morphologies of calcite and vaterite crystals. The formation of calcite was further corroborated by FT-IR and Raman analysis of bioprecipitates. The precultured bacteria were injected into the fine-grained soil together with cementation solution. Unconfined compressive strength in treated soil increased up to 1 MPa, and its calcium carbonate content increased by 2.78%. This, as well as the stability of the treated soil upon water immersion, proved the biocementation of the fine-grained soil. These findings suggest the potential of employing the CA biocementation route for soil stabilisation pending further development of the technique.

Bacillus toyonensis amplifies the immunogenicity of an experimental recombinant tetanus vaccine in horses

Probiotic microorganisms can stimulate an immune response and increase the efficiency of vaccines. For example, Bacillus toyonensis is a nonpathogenic, Gram-positive bacterium that has been used as a probiotic in animal supplementation. It induces immunomodulatory effects and increases the vaccine response in several species. This study aimed to evaluate the effect of B. toyonensis supplementation on the modulation of the immune response in horses vaccinated with recombinant Clostridium tetani toxin. Twenty horses were vaccinated twice, with an interval of 21 days between doses, and equally divided into two groups: the first group was supplemented orally for 42 days with feed containing viable spores of B. toyonensis (1 × 108) mixed with molasses (40 ml), starting 7 days before the first vaccination; the second (control) group received only feed mixed with molasses, starting 7 days before the first vaccination. Serum samples were collected to evaluate the humoral immune response using an in-house indirect enzyme-linked immunosorbent assay (ELISA), and peripheral blood mononuclear cells (PBMCs) were collected to evaluate cytokine transcription (qPCR). For the specific IgG-anti-rTENT titer, the supplemented group had ELISA values that were four times higher than those of the control group (p < 0.05). The supplemented group also showed higher ELISA values for the IgGa and IgGT sub-isotypes compared to the control group. In PBMCs stimulated with B. toyonensis, relative cytokine transcription of the supplemented group showed 15-, 8-, 7-, and 6-fold increases for IL1, TNFα, IL10 and IL4, respectively. When stimulated with a vaccine antigen, the supplemented group showed 1.6-, 1.8-, and 0.5-fold increases in IL1, TNFα, and IL4, respectively, compared to the control group. Horses supplemented with B. toyonensis had a significantly improved vaccine immune response compared to those in the control group, which suggests a promising approach for improving vaccine efficacy with probiotics.

Bioremediation of Crude Oil Contaminated Saline Soil Using a Bacterial Consortium and Different Carriers

AbstractBioremediation of crude‐oil‐contaminated soils is critical to supporting soil ecosystem health and functioning. Here, to explore the potential for different remediation strategies to restore soil microbial functioning and enhance remediation, three strains of bacteria, Bacillus toyonensis, Bacillus sp. and Bacillus cereus, were inoculated to saline, crude oil‐contaminated soil collected from Azadegan Oil Field, Iran. Bacteria were added using different carriers, including corn biochar, humic acid, chitosan and kaolin, and free bacteria as a control. Changes in soil metal concentrations and residual crude oil were determined after 60 days of incubation. Soil respiration, microbial biomass, and enzyme (dehydrogenase and catalase) activities were measured. The carriers accompanying a bacterial consortium were more efficient than free bacteria in removing crude oil and heavy metals from soil, and they performed better in removing n‐alkanes with carbon chains of C12–24. The oil removal rate and metal immobilization efficiencies were greatest in soils with chitosan‐bacteria treatment, with removal of crude oil, Al, Pb, Sr, and Cr (93%, 63%, 37%, 54%, and 15%, respectively) greater than for soils with free cells without treatment (61%, 54%, 9%, 50%, and 3%, respectively). Soil electrical conductivity decreased after application of bacterial mixtures with and without carriers. The inoculation of bacteria and application of soil amendments increased soil microbial biomass carbon and the activity of catalase and dehydrogenase. Overall, our results indicated the greatest potential remediation was achieved by applying immobilized microorganisms in chitosan to accelerate the biodegradation of crude oil and the removal of heavy metals.

Ayçiçeğinde Sclerotinia sclerotiorum (Lib.) De Bary’ye Karşı Bazı Bakteriyel Antagonistlerin In vitro ve In vivo Etkinliklerinin Belirlenmesi

This study was carried out in 2017-2018 to determine the in vitro and in vivo activities of some bacterial bioagents against Sclerotinia sclerotiorum, which causes root and root-collar rot in sunflower cultivation areas of Konya and Aksaray provinces. Against the two most virulent S. sclerotiorum (Hırkatol and Eskil) isolates selected as a result of pathogenicity tests after being isolated and diagnosed from diseased plants which were collected from sunflower cultivation areas in Konya and Aksaray provinces, the antifungal effects of 16 bacterial isolates from the soil in the rhizosphere region of the healthy sunflower plants from the same areas were evaluated. Primarily, the most effective bacterial bioagents were determined by dual culture tests. As a result of the in vitro tests, a total of 5 bacterial isolates constituting the largest zone diameter were molecularly identified according to 16S rRNA and were used in pot experiments. The bacteria were identified as Bacillus cereus, Bacillus simplex, Brevibacterium frigoritolerans, Bacillus toyonensis (2 isolates) and were coded using the BLAST program of the GenBank database (NCBI). As per in vitro, the highest effect in both isolates of S. sclerotiorum was observed in Bacillus cereus and Bacillus simplex with an inhibition rate of 49.19-57.95%. Except for Bacillus toyonensis (B1), one of the bacterial species which were tested in vivo, all the bacteria reduced or stopped lesion development compared to the control. As a result of the application, the biological control agent completely prevented the growth of both the isolates of Bacillus cereus and Bacillus simplex S. sclerotiorum in in vivo conditions (100%). Efficacy studies have shown that bacterial isolates both cause healthy growth of sunflower plants and significantly prevent disease formation in treated plants when compared to control plants. These results emphasize the importance of such studies as a tool for the development of sustainable agricultural practices that can be easily applied in our region, and also show that B. cereus and B. simplex in sunflowers can be potential bacterial bioagents that can be used in biological control against S.sclerotiorum. In addition, it will be useful to carry out studies on the development of commercial preparations of the bacterial isolates found in the study.

Potential of the quorum-quenching and plant-growth promoting halotolerant Bacillus toyonensis AA1EC1 as biocontrol agent.

The use of fertilizers and pesticides to control plant diseases is widespread in intensive farming causing adverse effects together with the development of antimicrobial resistance pathogens. As the virulence of many Gram-negative phytopathogens is controlled by N-acyl-homoserine lactones (AHLs), the enzymatic disruption of this type of quorum-sensing (QS) signal molecules, mechanism known as quorum quenching (QQ), has been proposed as a promising alternative antivirulence therapy. In this study, a novel strain of Bacillus toyonensis isolated from the halophyte plant Arthrocaulon sp. exhibited numerous traits associated with plant growth promotion (PGP) and degraded a broad range of AHLs. Three lactonases and an acylase enzymes were identified in the bacterial genome and verified invitro. The AHL-degrading activity of strain AA1EC1 significantly attenuated the virulence of relevant phytopathogens causing reduction of soft rot symptoms on potato and carrots. Invivo assays showed that strain AA1EC1 significantly increased plant length, stem width, root and aerial dry weights and total weight of tomato and protected plants against Pseudomonas syringae pv. tomato. To our knowledge, this is the first report to demonstrate PGP and QQ activities in the species B. toyonensis that make this strain as a promising phytostimulant and biocontrol agent.

The Complete Genome Sequence of Bacillus toyonensis Cbmb3 with Polyvinyl Chloride-Degrading Properties.

The accumulation of high amounts of plastic waste in the environment has raised ecological and health concerns, particularly in croplands, and biological degradation presents a promising approach for the sustainable treatment of this issue. In this study, a polyvinyl chloride (PVC)-degrading bacterium was isolated from farmland soil samples attached to waste plastic, utilizing PVC as the sole carbon source. The circular chromosome of the strain Cbmb3, with a length of 5,768,926 bp, was subsequently sequenced. The average GC content was determined to be 35.45%, and a total of 5835 open reading frames were identified. The strain Cbmb3 was designated as Bacillus toyonensis based on phylogenomic analyses and genomic characteristics. The bioinformatic analysis of the Cbmb3 genome revealed putative genes encoding essential enzymes involved in PVC degradation. Additionally, the potential genomic characteristics associated with phytoprobiotic effects, such as the synthesis of indole acetic acid and secondary metabolite synthesis, were also revealed. Overall, the present study provides the first complete genome of Bacillus toyonensis with PVC-degrading properties, suggesting that Cbmb3 is a potential strain for PVC bioremediation and application.

Common Bacillus mitigate tomato verticillium wilt and bacterial specks when combined with an essential oil extract

This study was conducted to evaluate the effect of growth promoting rhizobacteria (PGPR) alone and in combination with an essential oil (EO) extracted from Tetraclinis articulata (Vahl) Masters in protecting tomato plants against verticillium wilt and bacterial speck diseases. Three strains, identified as Bacillus toyonensis EI, Bacillus thuringiensis ES and Bacillus thuringiensis RA, possess in vitro PGPR activity such as the production of indole acetic acid and ammonia, and the solubilization of phosphates. In planta, they significantly increased the stem length, number of leaflets, leaf area, and root biomass. EO and the three strains, alone or in combination, were able to enhance photosynthetic parameters such as net photosynthesis and transpiration rate. They also significantly reduced leaf alteration (LA) index, stunting index (SI) and browning index (BI) caused by Verticillium dahliae kleb. In tomato. Reduction of LAI ranged from 25% to 37%, and it enhanced to more than 60% when plants were treated with EO combined with B. thuringiensis SE or with B. toyonensis EI, indicating a synergistic effect. Moreover, EO as well as the three Bacillus strains were also able to enhance tomato resistance against bacterial speck disease caused by Pseudomonas syringae pv. tomato. The average number of lesions was significantly reduced by the application of EO and the three strains, reaching 94% with combination of EO with B. thuringiensis RA. Bacterial population analyses showed that plants with reduced symptoms exhibited significantly lower bacterial concentrations. In tomato plants inoculated with V. dahliae results showed that EO as well as three strains were able to enhance H2O2 accumulation, at the late stage of infection, which might lead to reduce disease. However, within the pathosystem tomato/P. syringe pv. tomato, H2O2 accumulation was highly enhanced by the pathogen and inhibited after combined treatment.

Optimization of Growth Conditions for Chlorpyrifos-Degrading Bacteria in Farm Soils in Nakuru County, Kenya.

Chlorpyrifos (CP) is a chlorinated organophosphate pesticide. In Kenya, it is commonly used as an acaricide, particularly in dairy farming, leading to soil and water contamination. The study is aimed at isolating bacteria with CP-degrading potential and optimizing their growth conditions, including temperature, pH, and CP concentration. The enrichment culture technique was used, with minimal salt medium (MSM) supplemented with commercial grade CP. A multilevel factorial design was used to investigate the interactions of temperature, pH, and CP concentration. According to the findings, seven bacterial strains with potential to degrade CP were characterized and identified as Alcaligenes faecalis, Bacillus weihenstephanensis, Bacillus toyonensis, Alcaligenes sp. strain SCAU23, Pseudomonas sp. strain PB845W, Brevundimonas diminuta, and uncultured bacterium clone 99. Growth and biodegradation of bacteria differed significantly among the isolates across pH value, temperature, and concentrations (P ≤ 0.05). The optimum conditions for growth were pH 7, temperature of 25°C, and 25mg/l chlorpyrifos concentration, while optimum degradation conditions were pH 5, temp 25°C, and CP conc. 25mg/l. The Pearson correlation between optimum growth and degradation showed a weak positive relationship (R = 0.1144) for pH and strong positive relationship for temperature and concentration of chlorpyrifos. Other than pH, the study shows that there could be other cofactors facilitating the chlorpyrifos degradation process. The findings show that an efficient consortium, at 25°C and pH 5, can include Bacillus toyonensis 20SBZ2B and Alcaligenes sp. SCAU23 as they showed high optical density (OD) values under these conditions. These results indicate the potential for these bacteria to be employed in chlorpyrifos-contaminated ecosystem detoxification efforts upon manipulation of natural growth conditions. The findings of this study offer a potential foundation for future research into the reconstitution of a consortium. Based on the optimum conditions identified, the isolated bacterial strains could be further developed into a consortium to effectively degrade CP in both laboratory and field conditions. Dairy farmers can utilize the isolated strains and the consortia to decontaminate farm soils.

Metabolomics Reveals Lysinibacillus capsici TT41-Induced Metabolic Shifts Enhancing Drought Stress Tolerance in Kimchi Cabbage (Brassica rapa L. subsp. pekinensis).

Climate change has increased variable weather patterns that affect plants. To address these issues, we developed a microbial biocontrol agent against drought stress in kimchi cabbage (Brassica rapa L. subsp. pekinensis). We selected three bacterial strains (Leifsonia sp. CS9, Bacillus toyonensis TSJ7, and Lysinibacillus capsici TT41) because they showed a survival rate of up to 50% and good growth rate when treated with 30% PEG 6000. The three strains were treated with kimchi cabbage to confirm their enhanced drought stress resistance under non-watering conditions. Among the three strains, the TT41 treated group showed a significant increase in various plant parameters compared with the negative control on the 7th day. We performed extensive profiling of primary and secondary metabolites from kimchi cabbage and the TT41 strain. Multivariate and pathway analyses revealed that only the TT41 group clustered with the well-watered group and showed almost the same metabolome on the 7th day. When treated with TT41, lactic acid was identified as an indicator metabolite that significantly improved drought stress tolerance. Furthermore, lactic acid treatment effectively induced drought stress tolerance in kimchi cabbage, similar to that achieved with the TT41 strain.

Impact of dietary Bacillus toyonensis M44 as an antibiotic alternative on growth, blood biochemical properties, immunity, gut microbiota, and meat quality of IR broilers

Impact of dietary Bacillus toyonensis M44 as an antibiotic alternative on growth, blood biochemical properties, immunity, gut microbiota, and meat quality of IR broilers

Potential of Bacillus toyonensis and Paenibacillus alvei as Plant Growth Promoter on Melon Manis Terengganu (MMT)

Cucumis melo var inodorus cv. Manis Terengganu is known as Terengganu’s iconic fruits. However, MMT production is still insufficient to satisfy local demand. Over-reliance on chemical fertilizers to MMT has reduced soil fertility, degraded soil quality resistance, and negatively affected the environment. As a result, efficient microorganisms such as Paenibacillus alvei and Bacillus toyonensis were investigated as possible ecologically compatible biofertilisers for MMT. In this study, B. toyonensis and P. alvei produced indole-3-acetic acid (IAA) at concentrations of 20.49 µg.mL-1 and 19.18 µg.mL-1, respectively. hen, the greenhouse testing was conducted to evaluate the potentiality of effective microbes as plant growth promoter rhizobacteria by introducing the soil with B. toyonensis, P. alvei, and consortium. The experiment was laid out in a randomized complete block design (RCBD) with three groups of bacteria plus the control and each treatment replicated 15 times. Data were analyzed according to ANOVA procedure. As a result, B. toyonensis, P. alvei, and consortium significantly increased in all experimental growth parameters such as plant height, leaves, chlorophyll content, root mass, root length, leaf area, fruit weight, macronutrients, and micronutrients compared to control. Overall, the results showed that the effective single microbial strains promoted the development of MMT more effectively than the consortium

Engineered pine endophytic Bacillus toyonensis with nematocidal and colonization abilities for pine wilt disease control.

The pinewood nematode (PWN) is responsible for causing pine wilt disease (PWD), which has led to the significant decline of conifer species in Eurasian forests and has become a globally invasive quarantine pest. Manipulating plant-associated microbes to control nematodes is an important strategy for sustainable pest management. However, it has proven difficult to find pine-associated bacteria that possess both nematocidal activity and the ability to colonize pine tissues. The stress experiments with turpentine and pine tissue extract were carried out to screen for the desired target strain that could adapt to the internal environment of pine trees. This strain was used to construct an engineered nematocidal strain. Additionally, a fluorescent strain was constructed to determine its dispersal ability in Pinus massoniana seedlings through plate separation, PCR detection, and fluorescence microscopy observations. The engineered nematocidal strain was tested in the greenhouse experiment to assess its ability to effectively protect P. massoniana seedlings from nematode infection. This study isolated a Bacillus toyonensis strain Bxy19 from the healthy pine stem, which showed exceptional tolerance in stress experiments. An engineered nematocidal strain Bxy19P3C6 was constructed, which expressed the Cry6Aa crystal protein and exhibited nematocidal activity. The fluorescent strain Bxy19GFP was also constructed and used to test its dispersal ability. It was observed to enter the needles of the seedlings through the stomata and colonize the vascular bundle after being sprayed on the seedlings. The strain was observed to colonize and spread in the tracheid after being injected into the stems. The strain could colonize the seedlings and persist for at least 50 days. Furthermore, the greenhouse experiments indicated that both spraying and injecting the engineered strain Bxy19P3C6 had considerable efficacy against nematode infection. The evidence of the colonization ability and persistence of the strain in pine advances our understanding of the control and prediction of the colonization of exogenously delivered bacteria in pines. This study provides a promising approach for manipulating plant-associated bacteria and using Bt protein to control nematodes.

Genome sequences of seven bacterial isolates collected from soil as part of a microbiology lab course.

Soil is a source for diverse microbes that possess useful biotechnological capabilities. Here, we report the genome sequences of seven bacterial isolates from the species Exiguobacterium acetylicum, Rossellomorea marisflavi, Delftia acidovorans, Pseudomonas aeruginosa, Bacillus sp., and Bacillus toyonensis (two isolates) cultured from Dallas/Fort Worth metroplex soil samples.

Biological Control of Fusarium oxysporum, the Causal Agent of Fusarium Basal Rot in Onion by Bacillus spp.

&lt;i&gt;Fusarium oxysporum&lt;/i&gt; is the main pathogen causing Fusarium basal rot in onion (&lt;i&gt;Allium cepa&lt;/i&gt; L.), which incurs significant yield losses before and after harvest. Among management strategies, biological control is an environmentally safe and sustainable alternative to chemical control. In this study, we isolated and screened bacteria for antifungal activity against the basal rot pathogen &lt;i&gt;F. oxysporum&lt;/i&gt;. Isolates 23-045, 23-046, 23-052, 23-055, and 23-056 significantly inhibited &lt;i&gt;F. oxysporum&lt;/i&gt; mycelial growth and conidial germination. Isolates 23-045, 23-046, 23-052, and 23-056 suppressed the development of Fusarium basal rot in both onion seedlings and bulbs in pot and spray inoculation assays. Isolate 23-055 was effective in onion seedlings but exhibited weak inhibitory effect on onion bulbs. Based on analyses of the 16S rRNA and &lt;i&gt;rpoB&lt;/i&gt; gene sequences together with morphological analysis, isolates 23-045, 23-046, 23-052, and 23-055 were identified as &lt;i&gt;Bacillus thuringiensis&lt;/i&gt;, and isolate 23-056 as &lt;i&gt;Bacillus toyonensis&lt;/i&gt;. All five bacterial isolates exhibited cellulolytic, proteolytic, and phosphate-solubilizing activity, which may contribute to their antagonistic activity against onion basal rot disease. Taken together &lt;i&gt;B. thuringiensis&lt;/i&gt; 23-045, 23-046, 23-052, and 23-055 and &lt;i&gt;B. toyonensis&lt;/i&gt; 23-056 have potential for the biological control of Fusarium basal rot in onion.

Identification, Characterization, and Production Optimization of 6-Methoxy-1H-Indole-2-Carboxylic Acid Antifungal Metabolite Produced by Bacillus toyonensis Isolate OQ071612.

Fungal infections currently pose a real threat to human lives. In the current study, soil bacterial isolates were screened for the production of antifungal compounds to combat human fungal pathogens. Notably, the bacterial F1 isolate exhibited antimycotic action towards the Candida albicans ATCC 10231 and Aspergillus niger clinical isolates. By employing phenotypic and molecular techniques, we identified the F1 isolate as the Bacillus toyonensis isolate OQ071612. The purified extract showed stability within a pH range of 6-7 and at temperatures of up to 50 °C. It demonstrated potential antifungal activity in the presence of various surfactants, detergents, and enzymes. The purified extract was identified as 6-methoxy-1H-Indole-2-carboxylic acid using advanced spectroscopic techniques. To optimize the antifungal metabolite production, we utilized response surface methodology (RSM) with a face-centered central composite design, considering nutritional and environmental variables. The optimal conditions were as follows: starch (5 g/L), peptone (5 g/L), agitation rate of 150 rpm, pH 6, and 40 °C temperature. A confirmatory experiment validated the accuracy of the optimization process, resulting in an approximately 3.49-fold increase in production. This is the first documented report on the production and characterization of 6-methoxy-1H-Indole-2-carboxylic acid (MICA) antifungal metabolite from Bacillus toyonensis.

Effect of one or more microorganisms on the yield components of upland rice under greenhouse conditions

The use of beneficial microorganisms is an important strategy to improve rice production in a sustainable way. The study was carried out to determine the effect of single and combined beneficial microorganism on the development of upland rice. The experiment was performed in greenhouse and arranged in a completely randomized design with 29 treatments and 4 replications. Treatments consisted of rice seeds cultivar BRS A501 CL treated with single and combined multifunctional microorganisms (1 (Serratia marcescens), 2 (Bacillus toyonensis), 3 (Phanerochaete australis), 4 (Trichoderma koningiopsis), 5 (Azospirillum brasilense), 6 (Azospirillum sp.), 7 (Bacillus sp.), 8 to 28 (combination of all these microorganisms in pairs) and 29 (control)). Inoculation of upland rice with sole and combined microorganism on upland rice increased the roots and shoots development, yield components and grain yield of upland rice. The combinations of Bacillus sp. (BRM 63573) and A. brasilense (AbV5), Azospirillum sp. (BRM 63574) + B. toyonensis (BRM 32110) and Phanerochaete australis (BRM 62389) + Serratia marcenscens (BRM 32114) led to improved roots and shoots development; increased number of panicles and grains per pot, 1000 grains weight and grain yield of rice plants. Besides, the combinations allow helped in increased accumulation of nutrients in roots, shoots and grains of rice plants.

Comparable Evaluation of Nutritional Benefits of Lactobacillus plantarum and Bacillus toyonensis Probiotic Supplementation on Growth, Feed Utilization, Health, and Fecal Microbiota in Pre-Weaning Male Calves.

This study was conducted to investigate the impact of probiotic supplementation using Lactobacillus plantarum DSA 20174 and/or Bacillus toyonensis ATCC 55050 on growth performance, blood parameters, hematological measures, and fecal microbiota in pre-weaning Holstein calves. Thirty-two four-day-old male calves with a similar genetic background, weighing an average of 38.27 ± 0.12 kg, were randomly assigned to four groups. The groups consisted of a control group (CON) without supplementation, a group receiving B. toyonensis (BT) at 3 × 109 cfu/calf/day, a group receiving L. plantarum (LP) at 1 × 1010 cfu/calf/day, and a group receiving a combination of LP and BT (LP + BT) at half the dosage for each. The study found that calves supplemented with LP and LP + BT experienced significant improvements in average daily gain and final body weight compared to the control group. The LP + BT group showed the most positive effects on TDMI, starter intake, and CP intake. RBC counts tended to be higher in the probiotic groups, with the LP + BT group having the highest values. The LP + BT group also had higher total protein, albumin, globulin, and hematocrit concentrations. All probiotic groups showed higher serum IgG concentrations. Probiotic supplementation led to increased total bacterial count and decreased levels of E. coli, salmonella, and clostridium. The LP + BT group had a significant decrease in coliform count, while both LP and LP + BT groups had increased Lactobacillus populations. In conclusion, LP + BT probiotic supplement showed the most beneficial effects on growth, feed efficiency, blood constituents, and modulation of fecal microbiota composition.

Evaluation of Biocontrol Potential of Bacillus spp. and Pseudomonas fluorescens UM270 against Postharvest Fungal Pathogens

Fungal pathogens are the main causal agents of postharvest diseases of fruits and vegetables. To prevent this problem and avoid the use of harmful chemical fungicides, safer and greener alternatives have been sought. One of these alternatives is the use of plant-growth-promoting bacteria (PGPB). In this study, we evaluated in vitro four well-known PGPB strains (Pseudomonas fluorescens UM270, Bacillus toyonensis COPE52, Bacillus sp. E25, and Bacillus thuringiensis CR71) for their biocontrol potential against nineteen postharvest fungal pathogens. In vivo assays were also performed, and bacterial cells were inoculated on harvested strawberries and grapes with the pathogens Botrytis cinerea, Alternaria alternata, and Fusarium brachygibbosum to evaluate loss of firmness and disease incidence. Our results show that the four strains antagonized fungi in direct and indirect confrontation assays. Stronger antagonism was observed by the action of diffusible metabolites (DMs) compared to volatile organic compound (VOC) activity. All PGPB significantly improved the fruit firmness and reduced disease incidence caused by the fungal pathogens tested. However, strain UM270 showed excellent biocontrol activity, reducing the disease incidence of Fusarium brachygibbosum, Botrytis cinerea, and Alternaria alternata on strawberry fruits by 60%, 55%, and 65%, respectively. Diffusible antifungals and VOCs such as 2,4-diacetyl phloroglucinol, siderophores, auxins, fengycins, and N, N-dimethyl-hexadecyl amine, among others, might be responsible for the beneficial activities observed. These results suggest excellent biocontrol activities to inhibit postharvest pathogenic fungi and improve harvested fruit quality.

Bioelectrogeneic performance of air-cathode microbial fuel cells with diesel contaminants

Bioremediation of diesel contaminants and then harnessing the bioenergy could be another cost‐effective and eco‐friendly solution to hydrocarbons soil contaminants. Four series of parallel circuit air–cathode MFCs (100 mL working volume) were operated under different diesel concentrations using acclimated bacterial consortium from diesel contaminated soil. Maximum current (Imax = 43.11 mA) under applied potential was recorded using fuel cell (DMFC-31DMFC-3 = 50mlL−1 diesel concentration in microbial fuel cells.1) fed with 50 mlL−1 diesel (substrate), whereas it was 10 mA in DMFC-122DMFC-1 = 0mlL−1 diesel concentration in microbial fuel cells. (0 mlL−1), Imax of 9.6 mA in DMFC-23DMFC-2 = 10mlL−1 diesel concentration in microbial fuel cells.3(10 mlL−1) while in DMFC-444DMFC-4 = 100mlL−1 diesel concentration in microbial fuel cells. (100 mlL−1) Imax of 18.47 mA was recorded. Cyclic voltammogram and CLSM clearly indicated the effect of different diesel concentrations on the electrogenic performance of anode respiring bacteria (ARB). Six less explored, culturable species of ARB enriched bacteria on anodic biofilms in DMFC-3 were procured and characterized on molecular basis (16S rRNA gene) as Paenibacillus sp. (MN173851), Bacillus toyonensis (MN173853), Ochrobactrum sp. (MN173857), Bacillus sp. (MN173854), Bacillus methylotrophicus (MN173856), and Bacillus licheniformis (MN173855). Bioelectrochemical activity of Bacillus toyonensis (MN173853) was typically monitored for the first time in MFC reactors. Among the tested organisms, Bacillus sp., was found to have greatest biodegradation capability with rate of 88% followed by Paenibacillus sp. 85%, Ochrobactrum sp. 79% by fast decolourization of redox indicator. The present study verified the presence and suitability of ARB under the influence of diesel in MFCs.