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This study aimed to analyze the production of poly(3-hydroxybutyrate) (PHB) from lignocellulosic biomass through a series of steps, including microwave irradiation, ammonia delignification, enzymatic hydrolysis, and fermentation, using the Bacillus megaterium ATCC 14581 strain. The lignocellulosic biomass was first pretreated using microwave irradiation at different temperatures (180, 200, and 220 °C) for 10, 20, and 30 min. The optimal pretreatment conditions were determined using the central composite design (CCD) and the response surface methodology (RSM). In the second step, the pretreated biomass was subjected to ammonia delignification, followed by enzymatic hydrolysis. The yield obtained for the pretreated and enzymatically hydrolyzed biomass was lower (70.2%) compared to the pretreated, delignified, and enzymatically hydrolyzed biomass (91.4%). These hydrolysates were used as carbon substrates for the synthesis of PHB using Bacillus megaterium ATCC 14581 in batch cultures. Various analytical methods were employed, namely nuclear magnetic resonance (1H-NMR and13C-NMR), electrospray ionization mass spectrometry (EI-MS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA), to identify and characterize the extracted PHB. The XRD analysis confirmed the partially crystalline nature of PHB. [ABSTRACT FROM AUTHOR]

This study assessed the effect of Bacillus megaterium on seedling growth of Glycyrrhiza uralensis Fisch. under control and phosphorus (P) deficiency conditions. The results showed that P deficiency improved 1) G. uralensis root growth, 2) superoxide dismutase, catalase, and peroxidase activities, 3) inorganic P, starch, and soluble sugar contents in roots, 4) dissipated energy flux per reaction center, trapped energy flux per reaction center, and absorption flux per reaction center, and 5) net photosynthetic rate, stomatal conductance, transpiration rate, maximum fluorescence intensity after dark adaptation, and variable fluorescence. However, P deficiency significantly decreased chlorophyll and carotenoid contents in G. uralensis, but enhanced chlorophyll and carotenoid contents in B. megaterium. Our findings on the regulatory mechanisms of B. megaterium in response to P starvation hold promise for improving the success of G. uralensis cultivation. [ABSTRACT FROM AUTHOR]

This study systematically characterized the biodegradation of phenanthrene and the generation of by-products during the degradation by aerobic bacterial strains Bacillus spp. inhabited the phyllosphere of ornamental plants grown in urban polluted areas. The HPLC results revealed that four isolated Bacillus spp. (Bacillus sp.1—95%, Bacillus velezensis—90%, Bacillus megaterium—91%, Bacillus sp. P2B-02—93%) were able to degrade more than 88% of phenanthrene within the first 2 days of incubation with the specific growth rate of 0.0773 day−1, 0.0993 day−1, 0.0993 day−1, and 0.302 day−1, respectively. The results of the kinetic assay revealed that the isolated four bacterial strains followed the first-order kinetics, and out of them, Bacillus sp. P2B-02 had the shortest half-life (2.82 ± 0.07 days) and the highest specific growth rate of phenanthrene degradation (0.302 day−1). In addition to the phenanthrene peak, all four bacterial strains showed an additional peak in their chromatograms on the second and third incubation days. Furthermore, GC–MS analysis results revealed that the by-product formation during the phenanthrene degradation in all four Bacillus strains is identified as Phenol, 2-(phenylmethyl) (C13H12O) (molecular weight 184.0 g mol−1). Further HPLC analysis results revealed that nonetheless, that intermediate peak height gradually decreased until the sixth day, when it disappeared, indicating that some bacterial strains had completely degraded the by-products. According to the results, all four Bacillus spp. had greater than 50% of viability, confirming the non-toxicity of the by-products to the degrading bacterial strains. Furthermore, in toxicity assay with Vigna radiata, the appearance of the shoot and root from the seeds within 2 days confirmed that the highest concentration of by-product had no effect on seed growth and that the by-products produced were not harmful to the phyllosphere. Therefore, these phyllosphere Bacillus spp. can be used as efficient bioremediators which can clean phenanthrene-like polyaromatic hydrocarbon pollutants through phylloremediation. [ABSTRACT FROM AUTHOR]

There is no doubt that ruminants have the capability to digest lignocellulosic compounds and to utilize them as an absorbable form of energy by tapping into enzymes produced by the microbial population in their rumens. Among the rumens of various ruminants, this study focused on Korean goat rumens because of their unique digestibility of lignocellulosic biomasses. Therefore, a novel Gene12 gene was screened and unmasked from the constructed rumen metagenomic library of a Korean black goat and expressed in a Bacillus megaterium system. The recombinant protein was distinguished as a novel α-L-arabinofuranosidase enzyme from glycosyl hydrolase family 43 (GH43) for its capability to hydrolyze the non-reducing end of α-1,5-L-arabinofuranose linkages in α-L-arabinofuranosyl groups. The enzyme can also break apart α-L-arabinofuranosidic linkages and act synergistically with other hemicellulolytic enzymes to release α-1,2- and α-1,3-L-arabinofuranosyl groups from L-arabinose-comprising polysaccharides. In silico, phylogenetic, and computational analyses proclaimed that the Gene12 gene encodes a novel carbohydrate-active enzyme possessing a V-shaped indentation of the GH43 catalytic and functional domain (carbohydrate-binding module 6). The recombinant Gene12 protein has shared 81% sequence homology with other members of the GH43 family. Enzymic synopses (optimal pH, temperatures, and stability studies) of the recombinant Gene12 enzyme and its substrate specificity (synthetic and natural substrates) profiling were considered. The recombinant Gene12 α-L-arabinofuranosidase works best at pH 6.0 and 40 °C, and it is stable at pH 4.0 to 7.0 at temperatures of 20 to 50 °C. Additionally, 5-blended β-sheets were identified through a tertiary (3D) structure analysis along with the high substrate specificity against p-nitrophenyl-D-arabinofuranoside (pNPA). The highest substrate specificity of pNPA for Gene12 α-L-arabinofuranosidase indicated its confirmation as an exo-type arabinofuronidase. The results thus propose using the Gene12 protein as an exo-mannered GH43 α-L-arabinofuranosidase (EC 3.2.1.55) enzyme.

Using microorganisms to enhance crop productivity is an active and increasing field of research, which encompasses the productive, environmental, and economic aspects of agricultural production to obtain high-quality crops with a reduction in the need for fertilizers. Among the nutrients necessary for plant growth, phosphorous is problematic due to its low availability and its susceptibility to convert into non-labile forms. In this regard, phosphate-solubilizing bacteria (PSB) can be an interesting tool to improve phosphorous availability and to reduce the requirements of phosphate fertilizers. This work aimed to evaluate the potential use of phosphate-solubilizing bacteria in the supply of phosphorus and soybean development. This study was conducted in the 2019/2020 and 2020/2021 harvests. The experimental design was in randomized blocks, containing seven treatments and six replicates. The treatments consisted of five doses of phosphate fertilization, using triple superphosphate fertilizer, associated with the application of Bacillus subtilis and Bacillus megaterium bacteria, and two treatments, with and without the use of phosphorous fertilizer and without the use of an inoculant. Plant tissue nutrients and biometric and productive parameters of the crop were assessed. According to the observed results, applying PSB associated with phosphate fertilization and phosphate fertilization alone did not influence soybean’s nutritional, biometric, and productive parameters in the two harvests. Thus, the application of B. subtilis and B. megaterium, either associated or not associated with phosphate fertilization, does not contribute to the nutrition, development, and yield of soybean crops in soil with a naturally low P content, considering the climatic and soil conditions of the study.

Site-selective protein-protein coupling has long been a goal of chemical biology research. In recent years, that goal has been realized to varying degrees through a number of techniques, including the use of tyrosinase-based coupling strategies. Early publications utilizing tyrosinase from Agaricus bisporus(abTYR) showed the potential to convert tyrosine residues into ortho-quinone functional groups, but this enzyme is challenging to produce recombinantly and suffers from some limitations in substrate scope. Initial screens of several tyrosinase candidates revealed that the tyrosinase from Bacillus megaterium (megaTYR) is an enzyme that possesses a broad substrate tolerance. We use the expanded substrate preference as a starting point for protein design experiments and show that single point mutants of megaTYR are capable of activating tyrosine residues in various sequence contexts. We leverage this new tool to enable the construction of protein trimers via a charge-directed sequential activation of tyrosine residues (CDSAT).

Glucose and xylose are fermentable sugars readily available from lignocellulosic biomass, and are a sustainable carbon substrate supporting industrial biotechnology. Three strains were assessed in this work – Paraburkholderia sacchari , Hydrogenophaga pseudoflava , and Bacillus megaterium – for their ability to uptake both C 5 and C 6 sugars contained in a hardwood hydrolysate produced via a thermomechanical pulping-based process with concomitant production of poly(3-hydroxyalkanoate) (PHA) biopolymers. In batch conditions, B. megaterium showed poor growth after 12 h, minimal uptake of xylose throughout the cultivation, and accumulated a maximum of only 25 % of the dry biomass as PHA. The other strains simultaneously utilized both sugars, although glucose uptake was faster than xylose. From hardwood hydrolysate, P. sacchari accumulated 57 % of its biomass as PHA within 24 h, whereas H. pseudoflava achieved an intracellular PHA content of 84 % by 72 h. The molecular weight of the PHA synthesized by H. pseudoflava (520.2 kDa) was higher than that of P. sacchari (265.5 kDa). When the medium was supplemented with propionic acid, the latter was rapidly consumed by both strains and incorporated as 3-hydroxyvalerate subunits into the polymer, demonstrating the potential for production of polymers with improved properties and value. H. pseudoflava incorporated 3-hydroxyvalerate subunits with at least a 3-fold higher yield, and produced polymers with higher 3-hydroxyvalerate content than P. sacchari. Overall, this work has shown that H. pseudoflava can be an excellent candidate for bioconversion of lignocellulosic sugars to PHA polymers or copolymers as part of an integrated biorefinery. [Display omitted] • Three strains were evaluated to convert hardwood hydrolysate into PHA biopolymers. • Hydrogenophaga pseudoflava accumulated up to 84 % of its cell mass as PHA. • This strain also synthesized at least two-fold higher molecular weight polymers. • The strain displayed three-fold higher propionate-to-3-hydroxyvalerate yields. • H. pseudoflava may be promising for PHA production in an integrated biorefinery. [ABSTRACT FROM AUTHOR]

The use of phosphate-solubilizing bacteria (PSB) can be a sustainable strategy to increase phosphorus availability and promote satisfactory crop yields. The objective of this study was to evaluate whether inoculation with PSB in common bean increases (i) growth, (ii) nutrition, (iii) yield, and (iv) grain quality, and (v) reduces the chemical phosphorus application dose to obtain maximum yields. The experiment was conducted in an Oxisol using a randomized block design in a 4 × 4 factorial scheme, with four replicates, using the cultivar IAC 2051. The first factor was four doses of P2O5 (0, 20, 40 and 60 kg ha−1), and the second factor was four doses of PSB (0, 100, 200 and 300 mL ha−1). For leaf area and leaf chlorophyll content, the association of PSB inoculation with a P2O5 dose of 40 kg ha−1 promoted the best conditions for the common bean. P2O5 application increased yield by 79 kg ha−1 for each 10 kg ha−1 added. PSB inoculation at a dose of 192 mL ha−1 promoted P export of 15.3 kg ha−1, and the PSB dose of 159 mL ha−1 increased yield by 389 kg ha−1 (12%) compared to the control. Grain quality remained within the standards required by the consumer market, being little affected by the treatments. Improvements in common bean growth and nutritional and physiological status promoted by P2O5 application and PSB were essential in increasing yield, so these are sustainable production strategies. [ABSTRACT FROM AUTHOR]

In-situ utilization of lunar soil resources will effectively improve the self-sufficiency of bioregenerative life support systems for future lunar bases. Therefore, we have explored the microbiological method to transform lunar soil into a substrate for plant cultivation. In this study, five species of phosphorus-solubilizing bacteria are used as test strains, and a 21-day bio-improving experiment with another 24-day Nicotiana benthamiana cultivation experiment are carried out on lunar regolith simulant. We have observed that the phosphorus-solublizing bacteria Bacillus mucilaginosus, Bacillus megaterium, and Pseudomonas fluorescens can tolerate the lunar regolith simulant conditions and dissociate the insoluble phosphorus from the regolith simulant. The phosphorus-solubilizing bacteria treatment improves the available phosphorus content of the regolith simulant, promoting the growth of Nicotiana benthamiana. Here we demonstrate that the phosphorus-solubilizing bacteria can effectively improve the fertility of lunar regolith simulant, making it a good cultivation substrate for higher plants. The results can lay a technical foundation for plant cultivation based on lunar regolith resources in future lunar bases. The phosphorus-solubilizing bacteria Bacillus mucilaginosus, Bacillus megaterium, and Pseudomonas fluorescens can improve the growth of Nicotiana benthamiana in lunar regolith simulant by effectively dissociating insoluble inorganic phosphorus. [ABSTRACT FROM AUTHOR]

In the present study, novel bis‐Schiff base derivatives of polyhydroquinoline were synthesized through Hantzsch condensation reaction in excellent yields. Initially, a mixture of dimedone, ethyl acetoacetate, ammonium acetate and esterified aldehydes were refluxed in ethanol for 7–9 hrs. Then, hydrazine hydrate was treated with obtained polyhydroquinoline to form bis‐hydrazide of corresponding polyhydroquinoline. Finally, the bis‐hydrazide was independently refluxed with substituted aromatic aldehydes to get desired bis‐Schiff base derivatives of polyhydroquinoline. The new derivatives were confirmed by modern spectroscopic techniques such as 1H‐NMR, 13C‐NMR and HR‐ESI‐MS. The targeted compounds were evaluated for their antibacterial activity using disc diffusion method. The derivative with four OH‐group was found more effective against Bacillus megaterium, Bacillus subtilis IM, Bacillus subtilis ATCC, Salmonella enterica and Proteus vulgaris FMC II with zone of inhibition 8.3, 7.6, 7.3, 6.6 and 6.3 mm, respectively. DFT study of targeted compounds were performed on both materials studio and Gaussian 09 package, which showed good agreement with experimental data. The NLO of synthesized compounds were calculated and consider good candidates for NLO. The global reactivity, NBO and 1H‐NMR correlation were also studied, which showed good agreement. The cheap reagents, short reaction time and excellent yields are some features of current work. [ABSTRACT FROM AUTHOR]

Sulphur, available in the form of sulphate, is one of the essential nutrients that is required by plants. Bacteria capable of oxidizing reduced forms of sulphur to sulphate play an important role in sulphur nutrition for plants. The present study was conducted to isolate, screen, and characterize sulphur-oxidizing bacteria from different soil samples collected from mustard rhizosphere and fly ash mixed soil. A total of 33 sulphur-oxidizing bacterial isolates (HMSOB1-33) were retrieved from soil and further screened for sulphur-oxidizing ability. Maximum solubilization index (3.76), pH reduction (3.93), and sulphate production (173.61 µg/ml) were observed for the isolate HMSOB2 which on the basis of 16S rDNA sequencing was identified as Pantoea dispersa with sequence similarity 98.22%. Four other selected bacterial isolates were identified as Bacillus megaterium, Bacillus tropicus, Bacillus velezensis, and Bacillus cereus. Sulphate solubilization index (SSI) correlated positively (r = 0.91) with sulphate production; however, pH showed negative correlation (r = − 0.82) with SSI as well as sulphate production after 120 h of incubation. These promising bacterial isolates could be further explored as bioinoculant after assessing plant growth traits. [ABSTRACT FROM AUTHOR]

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The effects of four nematicidal rhizobacterial isolates; Bacillus subtilis, Bacillus pumilus, Bacillus megaterium, and Bacillus cereus on infection and multiplication of root‐knot nematode, Meloidogyne incognita on tomato were compared with the application of a chemical nematicide, fluopyram 34.48% SC (Velum Prime). The bio‐efficacy trial conducted in pots preinoculated with the above isolates followed by M. incognita inoculation resulted in a significant reduction in percent root galling viz. 91.95 in B. subtilis, 84.21 in B. pumilus, 83.70 in B. megaterium, and 81.8 in B. cereus, at 75 days after inoculation (DAI). The reproduction factor of the nematode was the lowest (15.83) in B. subtilis, followed by B. pumilus (21.00), compared with 48.16 in control, with enhanced photosynthetic and transpiration rates. The mechanism of induced resistance was assessed using quantitative reverse‐transcription polymerase chain reaction (qRT‐PCR) for quantification of three key defense genes (PR‐1b, JERF3, and CAT) at 0,2,4,8 and16 days DAI. The defence genes, PR‐1b, JERF3, and CAT were expressed at 2.5–7.5‐folds in rhizobacterialtreated plants, but not in nematicide treatment. The defense enzymes viz., super oxide dismutase (SOD), polyphenol oxidase (PPO), peroxidase (PO), and phenylalanine ammonia lyase (PAL) when quantified (μmol/mg protein) showed an increase from 1.5 to 17.5 for SOD, 2.1 to 7.8 in PPO, 1.8 to 10.2 in PO, and 1.8 to 8.7 in PAL during 0 to 16 DAI, in rhizobacteria‐treated plants. [ABSTRACT FROM AUTHOR]

The P450 monooxygenase CYP109A2 from Bacillus megaterium DSM319 was previously found to convert vitamin D3 (VD3) to 25‐hydroxyvitamin D3. Here, we show that this enzyme is also able to convert testosterone in a highly regio‐ and stereoselective manner to 16β‐hydroxytestosterone. To reveal the structural determinants governing the regio‐ and stereoselective steroid hydroxylation reactions catalyzed by CYP109A2, two crystal structures of CYP109A2 were solved in similar closed conformations, one revealing a bound testosterone in the active site pocket, albeit at a nonproductive site away from the heme‐iron. To examine whether the closed crystal structures nevertheless correspond to a reactive conformation of CYP109A2, docking and molecular dynamics (MD) simulations were performed with testosterone and vitamin D3 (VD3) present in the active site. These MD simulations were analyzed for catalytically productive conformations, the relative occurrences of which were in agreement with the experimentally determined stereoselectivities if the predicted stability of each carbon‐hydrogen bond was taken into account. Overall, the first‐time determination and analysis of the catalytically relevant 3D conformation of CYP109A2 will allow for future small molecule ligand screening in silico, as well as enabling site‐directed mutagenesis toward improved enzymatic properties of this enzyme. [ABSTRACT FROM AUTHOR]

Polyvinylpyrrolidone (PVP) fibers embedded with Zinc Oxide nanoparticles (ZnO NPs) were prepared by the centrifugal spinning of aqueous PVP solutions and ZnO NPs. The ZnO NPs were synthesized and coated with either cetyltrimethylammonium bromide or hexadecyltrimethylammonium bromide. The structure and morphology of the nanocomposite fibers were studied using scanning electron microscopy, X‐ray diffraction, energy‐dispersive X‐ray spectroscopy, Fourier transformed infrared spectroscopy and Thermogravimetric analysis. The effect of surfactant coating on the antibacterial activity of ZnO NPs and PVP/ZnO nanocomposite fibers against Escherichia coli (E. coli) and Bacillus megaterium (B. megaterium) bacteria was systematically investigated. The present study indicated that coating the ZnO NPs with surfactants resulted in large and uniform inhibition of bacterial growth. [ABSTRACT FROM AUTHOR]

Hydrocarbon pollution is one of the major environmental challenges facing the Niger Delta region of Nigeria, and over the years, various methods and strategies have been suggested to be used in tackling these problem. This research was aimed at restoring crude oil contaminated soil with locally formulated bioremediation agent (coded LOFBA). The local bioremediation agent (LOFBA) formulated consisted of cow dung, chicken droppings and periwinkle shells. Four soil treatments (unpolluted soil, polluted soil with crude oil, polluted soil remediated with LOFBA and polluted soil remediated with NPK) were setup using completely randomized blocked design (CRBD). The microbial isolates were identified on the basis of cultural, morphological and biochemical characteristics. Physicochemical properties of the soil (pH, total nitrogen, sulphate, phosphorus, total organic carbon, moisture, exchangeable cations, heavy metals) were estimated using standard procedures while total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbons (PAH) were determined using the gas chromatography-mass spectroscopy (GCMS). The LOFBA had pH 5.6, high calcium (47.325%), Nitrogen (1.49%), phosphorus (0.26%), electrical conductivity (194.81μmho/cm) and high counts of bacteria and fungi. The microbial isolates identified were Bacillus subtilis, Bacillus megaterium, Bacillus cereus, Acinetobacter aceti, Corynebacterium diphtheriae, Pseudomonas aeruginosa and Streptococcus pyogenes. Soil remediated with LOFBA showed a significantly (p < 0.05) higher bacterial counts total nitrogen and exchangeable ions (K, Mg, Na and Ca) than other treatments. Heptadecane, pristine, octadecane, eicosane, herieicosane and hentriacontane were more highly degraded in LOFBA remediated soil than NPK remediated soil. Naphthalene was the only PAH present in all soil samples after six months although LOFBA remediated soil had the lowest concentration. Besides, Acenaphylylene was detected in crude oil contaminated soil and soil remediated with NPK while none was detected in soil remediated with LOFBA. The results also revealed that total petroleum hydrocarbon (TPH) from unamended soil decreased from 21.33 mg/kg to 16.61 mg/kg (22.13% degradation), from 15.18 mg/kg to 3.03 mg/kg (80.04% degradation) in LOFBA remediated soil while that of NPK remediated soil decreased from 18.70 mg/kg to 7.97 mg/kg (57.38% degradation) after six months. The results indicate that the locally formulated bioremediation agent (LOFBA) enhanced the recovery of the oil contaminated soil better than NPK fertilizer. LOFBA is therefore, recommended for oil spill remediation in the tropic. [ABSTRACT FROM AUTHOR]

Aims: Moss biocrusts are important functional components of dryland soils. They could potentially be used to restore degraded dryland soils, but in sandy deserts, few cases of successful restoration have been reported. In this study, we investigated the growth-promoting effects of exogenous additives on moss biocrusts on sandy soils and their potential underlying mechanisms. Methods: A field-based study was used to examine the effects of inoculation by bacteria (Actinomyces bovis, Bacillus megaterium) and algae (Chlorella vulgaris, Microcoleus vaginatus), bound with Artemisia sphaerocephala gum, on the growth of mosses on a sandy soil. We used 16S and 18S rRNA amplicon sequencing and microbial co-occurrence ecological network analysis to examine the structure and interaction of the microbial community under the best performing inoculation treatment in different moss development stages. Results: The addition of exogenous microorganisms promoted moss biocrust growth. The best inoculation treatment was achieved with the addition of Actinomyces bovis and Chlorella vulgaris, which resulted in greater moss cover, height and density than the control. The addition of exogenous microorganisms improved microbial richness and diversity, and altered soil microbial community structure and assemblage, such as increasing the relative abundance of Streptophyta, which was associated with greater moss biocrust growth. Moreover, exogenous microorganisms strengthened the interactions among microbes and microbial community stability, and accelerated the degradation of soil organic carbon (SOC) and total nitrogen (TN). Conclusions: Our findings reveal the growth-promoting mechanisms of microbial inoculation, which could provide a cost-effective method of restoring moss biocrusts in sandy deserts, offering new perspectives for dryland ecological restoration. [ABSTRACT FROM AUTHOR]

Background and Objectives: Plant growth-promoting bacteria (PGPB) may reduce the negative effects of salinity stress. The aim of this study was to optimize Bacillus megaterium RTS1 and characterize the effect of the PGPB on the physiological characteristics of tomato (Lycopersicon esculentum). Materials and Methods: The Central composite design (CCD) of response surface methodology (RSM) was used to optimize Bacillus megaterium RTS1 to produce maximum cell biomass and spores. Then the effect of the PGPB on the physiological characteristics of tomato (Lycopersicon esculentum), including membrane stability, leaf relative water content percentage, anthocyanin and carotenoids content, chlorophyll photosynthetic parameters, sugar and starch level, superoxide anion and antioxidant activity under salt stress conditions. The NFB medium was inoculated with 5% bacterial culture and the fermentation was carried out in a 10-lit fermenter. Results: After optimization, the amount of cell biomass by the model was 9.45 log10 CFUs/mL, which showed a 1.2-fold increase compared to the non-optimized medium. Usage of bacteria under the optimal conditions of the culture medium may increase the stability of the membrane and improve the relative water content. Bacteria were able to prevent the excessive increase of anthocyanins. Oxidative stress led to an increase in the content of chlorophyll a, while causing the degradation of chlorophyll b. Bacterial inoculation led to an increase in the level of sugar and starch compared to the control. PGPB showed an increasing effect on the amount of superoxide anion production and caused a significant increase in the antioxidant activity under salinity stress conditions. Conclusion: The PGPB can be a promising way to boost physiological characteristics of tomato plant under salinity stress. Also, sporulation capacity of Bacillus megaterium with high bacterial cell density in fermenter produce a sustainable product for tomato plants. [ABSTRACT FROM AUTHOR]

This study explored self-healing in geopolymer mortar cured at ambient temperature using polypropylene fibers and bacterial co-cultures of Bacillus subtilis and Bacillus megaterium. Damage degree, compressive strength, ultrasonic pulse velocity (UPV), strength-regain percentage, and self-healing percentage were evaluated. A full factorial design was used, which resulted in an eight-run complete factorial design with four levels in the first factor (polypropylene content: 0%, 0.25%, 0.5%, and 0.75%) and two levels in the second factor (bacteria concentration: 0 (without) and 1 (with)). The results indicate that increasing the polypropylene fiber content enhanced strength regains up to 199.97% with 0.75% fibers and bacteria. The bacteria alone improved strength-regain percentages by 11.22% through mineral precipitation. The analysis of variance (ANOVA) showed no interaction between fibers and bacteria, but both independently improved the compressive strength. Only bacterial samples exhibited positive self-healing, ranging from 16.77 to 147.18%. The analysis using a scanning electron microscope with energy dispersive X-ray (SEM-EDX) and X-ray fluorescence (XRF) also revealed greater calcite crystal formation in bacterial samples, increasing the strength-regain and self-healing percentages. The results demonstrate that polypropylene fibers and bacteria cultures could substantially enhance the strength, durability, and self-healing percentage of geopolymer mortars. The findings present the potential of a bio-based self-healing approach for sustainable construction and repair materials. [ABSTRACT FROM AUTHOR]

Background: Over the previous two decades, Plasmodium falciparum strains have become increasingly resistant to several medications. As a result, there is an urgent need to develop new therapeutic options. Taking this into account, we focused our research on screening microbial extracts from rhizosphere soil samples in specific regions, which increases the likelihood of discovering bacteria capable of producing antiplasmodial activity. Results: In the current study, we aimed to isolate thirty-two different medicinal plant rhizosphere soil samples collected from Kolli Hills (January–December 2016). Isolation was performed on nutrient and starch casein agar medium by serial dilutions, and distinct colonies were chosen from each dilution. A total of two seventy-five bacterial isolates were isolated from the research plants and kept as pure cultures on nutrient agar. In which, maximum count of fourteen Gram-positive spore forming bacilli strains have been identified and further evaluated for morphological, cultural, and biochemical traits and significantly identified as Bacillus species. Further, promising anti-plasmodial action was demonstrated by B. megaterium bacterial extracts, with IC50 values of 24.65 µg/mL at 24 h and 7.82 µg/mL at 48 h. Bacillus mycoides showed good antiplasmodial activity with (IC50P. falciparum 3D7: 23.52 μg/mL at 24 h and 22.88 μg/mL at 48 h, Bacillus flexus showed IC50 of 18.36 and 6.24 μg/mL and moderate antiplasmodial activity observed in Bacillus tequilensis. Poor antiplasmodial activity was found in Bacillus subtillis, Bacillus macerans, Bacillus pumilus and Bacillus larvey. Interestingly, 16S rRNA sequencing results confirmed that our bacterial species was Bacillus megaterium with 99% similarity observed with the accession number KX495303.1. Additionally, GC–MS analysis revealed effective anti-plasmodial bioactive compounds. Conclusions: These findings show the potential of B. megaterium from Achyranthes aspera as a antiplasmodial agent. However, more research is needed to fully understand the bioactive compound of these strains and further studies are necessary to explore drug formulation and toxicity levels in the future. [ABSTRACT FROM AUTHOR]

Bacillus thuringiensis (Bt) produces, during its vegetative growth, some insecticidal proteins that are secreted and diluted into the culture medium. These proteins are commonly known as vegetative insecticidal proteins (Vips), and include binary Vpb/Vpa proteins (formerly known as Vip1/Vip2) with coleopteran activity; Vip (formerly Vip3) with activity against lepidopterans; and Vpb4 proteins (formerly Vip4), also with coleopteran activity. Vip proteins are highly toxic to different species of lepidopteran pests; however, the difficulty in producing them in a concentrated form has not allowed their development as formulated biopesticides, and they are relegated to only being produced in transgenic crops. In this work, we demonstrated that the gene encoding the Vip protein Vip3Ag4 could be successfully expressed in an asporogenic strain of Bacillus megaterium using (D)-xylose as a low-cost inductor. Under certain conditions (37 °C and induction with 0.5% w/v xylose), active Vip3Ag4 protein was primarily produced in soluble form, remaining encapsulated within the cell wall of B. megaterium. After treatment with lugol (1% for 4 h), induced cells were completely killed (fixed) but maintained the functional Vip3Ag4 protein, which resulted in above 95% mortality against first-instar larvae of Chrysodeixis chalcites, Helicoverpa armigera, Spodoptera exigua, S. frugiperda, S. littoralis and Trichoplusia ni. The fact that the recombinant Vip3Ag4 protein was successfully produced in a soluble and an active form in this bacterium (with a low-cost inductor) suggests that B. megaterium is one of the hosts of choice for the production of sprayable formulations in "killed-microbial pesticides", based on Vip3 proteins from Bt. [ABSTRACT FROM AUTHOR]

Cytochrome P450 monooxygenases CYP120As are the unique non-membrane P450s, which are extensively involved in retinoid biodegradation. As the O-functionalized 1,3,3-trimethylcyclohex-1-ene moiety exists in many bioactive compounds which could only be catalyzed by Class II P450s, exploration of the catalytic repertoire of CYP120As is therefore highly attractive. However, up to date, only one bacteriogenic candidate (CYP120A1) was demonstrated for the hydroxylation of C16 and C17 of retinoic acid, by utilizing the integral membrane protein cytochrome P450 reductase redox partner for the electron transfer. Herein, we provided an efficient prokaryotic functional expression system of CYP120As in E. coli by expression of the CYP120A1 coupled with several reductase partners. Fusion redox partners to the C-terminal of the heme-domain are also working on other CYP120A members. Among them, the fusion protein of CYP120A29 and FAD/FMN reductase from Bacillus megaterium P450BM3 (CYP101A2) showed the highest expression level. Based on the available translational fusion systems, the regioselectivity and the substrate scope of the CYP120As have also been explored. This work represents a good starting point for further expanding the catalytic potential of CYP120 family. Key Points: • Characterization of CYP120As in E. coli is firstly achieved by constructing fusion proteins. • The feasibility of three P450 reductase domains to CYP120As was evaluated. • Hydroxylated products of retinoic acid by six CYP120As were sorted and analyzed. [ABSTRACT FROM AUTHOR]

Using microorganisms to enhance crop productivity is an active and increasing field of research, which encompasses the productive, environmental, and economic aspects of agricultural production to obtain high-quality crops with a reduction in the need for fertilizers. Among the nutrients necessary for plant growth, phosphorous is problematic due to its low availability and its susceptibility to convert into non-labile forms. In this regard, phosphate-solubilizing bacteria (PSB) can be an interesting tool to improve phosphorous availability and to reduce the requirements of phosphate fertilizers. This work aimed to evaluate the potential use of phosphate-solubilizing bacteria in the supply of phosphorus and soybean development. This study was conducted in the 2019/2020 and 2020/2021 harvests. The experimental design was in randomized blocks, containing seven treatments and six replicates. The treatments consisted of five doses of phosphate fertilization, using triple superphosphate fertilizer, associated with the application of Bacillus subtilis and Bacillus megaterium bacteria, and two treatments, with and without the use of phosphorous fertilizer and without the use of an inoculant. Plant tissue nutrients and biometric and productive parameters of the crop were assessed. According to the observed results, applying PSB associated with phosphate fertilization and phosphate fertilization alone did not influence soybean's nutritional, biometric, and productive parameters in the two harvests. Thus, the application of B. subtilis and B. megaterium, either associated or not associated with phosphate fertilization, does not contribute to the nutrition, development, and yield of soybean crops in soil with a naturally low P content, considering the climatic and soil conditions of the study. [ABSTRACT FROM AUTHOR]

Cytochrome CYP102A1 (P450 BM3) of Priestia megaterium (bas. Bacillus megaterium) has several unique functional features and thus provides an ideal object for directed evolution and other synthetic applications. Previously, the CYP102A1-LG23 mutant with 14 mutations in the heme part was obtained that hydroxylates several androstanes at C7β with the formation of products with the anti-inflammatory and neuroprotective activities. In this study, synthetic cyp102A1-LG23 gene encoding the P450 BM3 mutant was expressed as a component of either monocistronic operon or bicistronic operon containing the gdh (glucose dehydrogenase, GDH) or zwf2 (glucose 6-phosphate dehydrogenase, G6PD) gene in Mycolicibacterium smegmatis BD cells. The recombinant bacteria were able hydroxylate androst-4-ene-3,17-dione (AD) into 7β-OH-AD. Their biocatalytic activity was increased twice by increasing the solubility of CYP102A1-LG23 protein in the cells and supplementing the cells with the additional cofactor regeneration system by introducing GDH and G6PD. The maximum 7β-OH-AD yield (37.68 mol%) was achieved by co-expression of cyp102A1-LG23 and gdh genes in M. smegmatis. These results demonstrate the possibility of using synthetic genes to obtain recombinant enzymes and expand our understanding of the processes involved in steroid hydroxylation by bacterial cytochromes. The data obtained can be used to develop new approaches for microbiological production of 7β-hydroxylated steroids in genetically modified Mycolicibacterium species. [ABSTRACT FROM AUTHOR]

The effect of wheat and maize rotations and the application of plant-animal compost on potato bacterial wilt and yield was investigated. The proposed method was tested in three separate locations, each two acres in size, with an untreated control. The first two were naturally infested, but the third was pathogen-free. Infested locations that had been treated experienced a significant reduction in disease incidence. The addition of a bio-fertilizer mixture (Azotobacter sp., Azospirillum sp., Bacillus megaterium, and Bacillus circulans) improved the compost's suppressive potential. The method increased soil organic matter (SOM), N, P, K, Ca+2, and Mg+2 while decreasing Na+ levels and increasing potato yield. The relative abundance of Ralstonia decreased while that of Arthrobacter, Streptomyces, and Nocardioides increased. The presence of Gracilibacillus, Cellvibrio, Bacillus, and Paenibacillus was associated with a decrease in Ralstonia, whereas the presence of Propionibacterium (a nitrogen-fixing bacteria) was associated with an increase in Ralstonia. [ABSTRACT FROM AUTHOR]

Plant growth promoting bacteria (PGPB) boost plant development and promote soil bioremediation by secreting a variety of metabolites and hormones. Several important bacterial characteristics, such as biological nitrogen fixation, phosphate solubilization, ACC (1-aminocyclopropane-1-carboxylate) deaminase activity, and production of siderophores and phytohormones, can be assessed as plant growth promoting (PGP) traits. In the current study, three Bacillus megaterium strains and one Pseudomonas fluorescens strain have been investigated for their plant growth promoting abilities in vitro and in a hydroponic culture on barley. Firstly, these bacterial strains have been investigated for their salt (NaCl) tolerances and then phosphate solubilization, nitrogen fixation and the production of ammonia and indole-3-acetic acid. These bacterial strains were also inoculated with Hordeum vulgare in a hydroponic culture. The investigated bacterial strains were found to have different plant growth promoting activities even within same species (B. megaterium). In the hydroponic culture experiments, it was determined that comparing to the control group, the growth rates (total weight) of the plants enhanced with B. megaterium (FDG108), B. megaterium (FDG161), and B. megaterium (FDG2) ranged from 3.91, 43.45, and 73.73, respectively. Even these three bacteria were B. megaterium, the best result regarding the total plant weight was obtained with B. megaterium (FDG2). These results showed that even if many bacteria enhance plant growth, the use of better one is of vital importance in agriculture practice for production of food. [ABSTRACT FROM AUTHOR]

The specifics of the processing of livestock and poultry products is that in the process of obtaining the main marketable products, about half the feedstock at various stages of the technological process turns into waste that pollutes the environment. These by-products contain large amounts of the hard-to-digest keratin protein. The use of specific enzymes capable of degrading this protein helps not only to reduce the negative anthropogenic impact on nature but also to obtain valuable hydrolysates that can be used as a fertilizer for plants or a feed additive. The aim of this work was to study the ability of Bacillus megaterium UCM B-5710 to split various keratin-containing substrates: black and white chicken feathers, white turkey feathers, parrot feathers of various colors, sheep wool, pig bristles, and baby hair and nails. Methods. The culture was grown under conditions of submerged cultivation at 40 °C, with a nutrient medium stirring rate of 201 rpm for 6 days. For growth, a basic nutrient medium containing 0.5% defatted chicken feathers or other keratin-containing substrates as sole sources of carbon and nitrogen were used. Keratinase activity was assessed by UV absorption at 280 nm of hydrolysis products of keratin-containing raw materials. Protein was determined by the Lowry method, caseinolytic (total proteolytic) activity was determined by the Anson method modified by Petrova, and amino acid content was determined by the ninhydrin method. The degree of hydrolysis of the substrates was evaluated by the ratio of the initial and final weight of the substrate. Results. It was shown that the synthesis of keratinase by the culture of B. megaterium UCM B-5710 begins from the 6th hour of cultivation. The level of protein and proteolytic activity and the content of amino acids increased throughout the entire period of culture growth. The supernatant of the culture liquid of B. megaterium UCM B-5710 was most effective in splitting white chicken's and turkey's feathers, a little slower -- feathers of black chicken and blue parrots, as well as wool of white sheep. According to the degree of splitting, the substrates used can be arranged in the following order: white turkey feathers > white chicken feathers > black chicken feathers > blue parrot feathers > white sheep wool > baby nails > pig bristle > baby hair. The study of the effect of feather color on the resistance to decomposition showed that black, blue, and red feathers are more resistant, which coincides with the literature data. Conclusions. B. megaterium UCM B-5710 produces keratinase capable of splitting both α- and β-keratins, however, with different efficiencies and rates. [ABSTRACT FROM AUTHOR]

Beneficial health effects of omega-3 polyunsaturated fatty acids (n-3 PUFA) are partly attributed to specialized pro-resolving mediators (SPMs), which promote inflammation resolution. Strategies to improve n-3 PUFA conversion to SPMs may, therefore, be useful to treat or prevent chronic inflammatory disorders. Here, we explored a synbiotic strategy to increase circulating SPM precursor levels. Healthy participants (n = 72) received either SynΩ3 (250 mg eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) lysine salts; two billion CFU Bacillus megaterium; n = 23), placebo (n = 24), or fish oil (300 mg EPA plus DHA; N = 25) capsules daily for 28 days in a randomized, double-blind placebo-controlled parallel 3-group design. Biomarkers were assessed at baseline and after 2 and 28 days of intervention. The primary analysis involved the comparison between SynΩ3 and placebo. In addition, SynΩ3 was compared to fish oil. The synbiotic SynΩ3 comprising Bacillus megaterium DSM 32963 and n-3 PUFA salts significantly increased circulating SPM precursor levels, including 18-hydroxy-eicosapentaenoic acid (18-HEPE) plus 5-HEPE, which was not achieved to this extent by fish oil with a similar n-3 PUFA content. Omega-3 indices were increased slightly by both SynΩ3 and fish oil. These findings suggest reconsidering conventional n-3 PUFA supplementation and testing the effectiveness of SynΩ3 particularly in conditions related to inflammation.

The study focused on isolating bioflocculant-producing microorganisms from poultry slaughterhouse wastewater (PSW). Microorganisms (n = 20) were isolated, and the D2 isolate, identified as Bacillus megaterium using 16S rDNA and RpoD (sigma 70), had maximum flocculation activity. Furthermore, characteristics of the bioflocculant produced by B. megaterium were determined, and the optimum storage conditions, including the flocculation mechanism, were identified. The bioflocculant was composed mainly of polysaccharides and proteins and was better stored frozen in a crude form. Furthermore, the flocculation efficacy was assessed using response surface methodology at pH 4 (min) and 9 (max), bioflocculant dosage of 1% (min) and 3% (max, v/v), indicating pH 6.5 and dosage of 2% (v/v) as optimum flocculation conditions for floc formation under ambient temperature. These results were further confirmed with microscopy assessments with zeta potential measurements confirming that the bioflocculant was ionic, albeit charge neutralization was not the primary mechanism for floc agglomeration. Hydrogen bonding was predominant, indicative of a neutralization-bridging mechanism, an assertion also based on the functional groups prevalent in the isolate-B. megaterium. The results obtained indicate that bioflocculants can be used to treat isolates that are sourced from wastewater.

Bacillus megaterium is particularly known for its abundance in soils and its plant growth promotion. To characterize the metabolites excreted by this specie, we performed successive liquid/liquid extractions from bacteria culture medium with different polarity solvents (cyclohexane, dichloromethane, ethyl acetate and butanol) to separate the metabolites in different polarity groups. The extracts were characterized regarding their total phenolic content, the amount of reducing sugar, the concentration of primary amines and proteins, their chromatographic profile by HPLC-DAD-ELSD and their chemical identification by GC-MS. Among the 75 compounds which are produced by the bacteria, 19 identifications were for the first time found as metabolites of B. megaterium and 23 were described for the first time as metabolites in Bacillus genus. The different extracts containing B. megaterium metabolites showed interesting agronomic activity, with a global inhibition of seed germination rates of soya, sunflower, corn and ray grass, but not of corn, compared to culture medium alone. Our results suggest that B. megaterium can produce various metabolites, like butanediol, cyclic dipeptides, fatty acids, and hydrocarbons, with diverse effects and sometimes with opposite effects in order to modulate its response to plant growth and adapt to various environmental effects. These findings provide new insight into bioactive properties of this species for therapeutic uses on plants.

Background and Objectives: Plant growth-promoting bacteria (PGPB) may reduce the negative effects of salinity stress. The aim of this study was to optimize Bacillus megaterium RTS1 and characterize the effect of the PGPB on the physiological characteristics of tomato (Lycopersicon esculentum). Materials and Methods: The Central composite design (CCD) of response surface methodology (RSM) was used to optimize Bacillus megaterium RTS1 to produce maximum cell biomass and spores. Then the effect of the PGPB on the physiological characteristics of tomato (Lycopersicon esculentum), including membrane stability, leaf relative water content percentage, anthocyanin and carotenoids content, chlorophyll photosynthetic parameters, sugar and starch level, superoxide anion and antioxidant activity under salt stress conditions. The NFB medium was inoculated with 5% bacterial culture and the fermentation was carried out in a 10-lit fermenter. Results: After optimization, the amount of cell biomass by the model was 9.45 log10 CFUs/mL, which showed a 1.2-fold increase compared to the non-optimized medium. Usage of bacteria under the optimal conditions of the culture medium may increase the stability of the membrane and improve the relative water content. Bacteria were able to prevent the excessive increase of anthocyanins. Oxidative stress led to an increase in the content of chlorophyll a, while causing the degradation of chlorophyll b. Bacterial inoculation led to an increase in the level of sugar and starch compared to the control. PGPB showed an increasing effect on the amount of superoxide anion production and caused a significant increase in the antioxidant activity under salinity stress conditions. Conclusion: The PGPB can be a promising way to boost physiological characteristics of tomato plant under salinity stress. Also, sporulation capacity of Bacillus megaterium with high bacterial cell density in fermenter produce a sustainable product for tomato plants.

A comparison of the growth performance of Penaeus vannamei was ascertained by supplementing the potential probiotics isolated from a biofloc system incorporated through feed. Post-larvae shrimp (0.045 ± 0.005 g) were stocked at a density of 500/m3 in FRP tanks (500 L) in triplicates for a period of 60 days. A total of 40 bacterial strains were isolated from previous biofloc culture trials and tested for their antimicrobial activity against the pathogen Vibrio parahaemolyticus. Among these, Bacillus megaterium, Exiguobacterium profundum, Pseudomonas balearica, and Pseudomonas stutzeri showed higher antimicrobial activity. The treatment groups included clear water with no probiotics (CW), clear water + isolated probiotic (CW + IP), biofloc alone (BFT), and biofloc + isolated probiotic (BFT + IP), in triplicates. Distillery spent wash was used as a carbon source for biofloc development and maintenance. A probiotic concentration of 1 × 109 cfu/g was supplemented throughout the trial. The recorded water quality parameters (pH, alkalinity, calcium, and magnesium) were observed to be significant among the experimental groups (p ≤ 0.05). The highest weight gain (2.43 g), SGR, PER, and lower FCR values were recorded in BFT + IP. The lowest values of total Vibrio were found in BFT. The histology analysis revealed that there was a mild increase in the B and R cell vacuoles in the hepatopancreas of CW and BFT + IP, whereas mild degeneration was found in the intestine of CW and CW + IP. Microbiome analysis of the shrimp gut revealed that Proteobacteria was the most abundant phylum in all experimental groups. P. balearica, K. pneumoniae, P. stutzeri, and E. profundum were present in the gut of C, whereas P. balearica, K. pneumonia, and P. stutzeri were present in the gut of CW + IP and BFT + IP. The results proved that the probiotics isolated from biofloc colonized in shrimp gut could play a promising role in aquaculture. [ABSTRACT FROM AUTHOR]

Biofertilizers and organic fertilizers are eco-friendly treatments that reduce the consumption and problems associated with chemical fertilizers. The aim of this research was to investigate the effects of biofertilizers and organic fertilizers on reducing consumption and improving the effectiveness of chemical fertilizer treatments by comparing the growth parameters, yield, quality criteria, and nutrient concentration in lettuce and broccoli grown under greenhouse conditions. The biofertilizer (BM-MegaFlu®) comprised Bacillus megaterium, Pseudomonas fluorescens, and Pantoea agglomerans bacteria. The experiment consisted of six treatments comprising (1) biofertilizer (BF), (2) chemical fertilizer + biofertilizer (CF + BF), (3) chemical fertilizer (CF), (4) CF (1/2 dose) + BF, (5) CF (1/3 dose) + BF, and (6) organic fertilizer (OF + BF). BF did not adversely affect the head height and root collar diameter of lettuce; on the contrary, it showed non-significant differences with CF + BF, BF, CF (1/2) + BF, and CF (1/3) + BF treatments and CF alone. The highest total and marketable yields were obtained from CF + BF, CF, CF (1/2) + BF treatments in lettuce. The total yield was the highest in the CF + BF, CF, CF (1/2) + BF, and CF (1/3) + BF treatments in broccoli. In conclusion, the biofertilizer had a supportive effect on the use of chemical fertilizers in lettuce and broccoli production, especially the CF (1/2) + BF treatment in lettuce. The CF (1/2) + BF and CF (1/3) + BF treatments in broccoli showed similar yields to CF. In both crops, BF could provide 50% chemical fertilizer savings. [ABSTRACT FROM AUTHOR]

Concrete is one of the most used materials in the building sector. Inevitably, concrete gains strength and develops shrinkage cracks during the curing process. Shrinkage cracks provide an entry point for reactive fluids to get into the concrete core. Under favorable conditions, the fluids reduce the pH of the core and consequentially corrode the reinforcing bars. This research shows the use of Bacillus megaterium MTCC 3353, which produces calcium carbonate and closes the minute fissures. Part substitution of cement with metakaolin was also done in the study. It was seen that the bio-based concrete specimens enhanced the mechanical strength and durability parameters. The calcite precipitation was validated using a microstructure study. FESEM and XRD tests show the presence of calcite (calcium carbonate) inside the concrete structure. The bacteria were tested for their growth when superplasticizers were added to them. The bacteria showed normal growth compared to the conventional testing. [ABSTRACT FROM AUTHOR]

A total of thirty-two aerobic spore former strains were isolated from intestinal samples of healthy children and analyzed for their hemolytic and antibiotic-resistant activities. Four strains selected as non-hemolytic and sensitive to all antibiotics recommended as relevant by regulatory agencies were short-listed and evaluated for their in silico and in vitro probiotic potentials. The four selected strains were assigned to the Bacillus velezensis (MV4 and MV11), B. subtilis (MV24), and Priestia megaterium (formerly Bacillus megaterium) (MV30) species. A genomic analysis indicated that MV4, MV11, and MV24 contained a homolog of the gene coding for the fibrinolytic enzyme nattokinase while only MV30 encoded a glutamic acid decarboxylase essential to synthesize the neurotransmitter GABA. All four strains contained gene clusters potentially coding for new antimicrobials, showed strong antioxidant activity, formed biofilm, and produced/secreted quorum-sensing peptides able to induce a cytoprotective stress response in a model of human intestinal (HT-29) cells. Altogether, genomic and physiological data indicate that the analyzed strains do not pose safety concerns and have in vitro probiotic potentials allowing us to propose their use as an alternative to antibiotics. [ABSTRACT FROM AUTHOR]

Pearl millet (Pennisetum glaucum L.) is one of the major crops in dry and saline areas across the globe. During salinity stress, plants encounter significant changes in their physio and biochemical activities, leading to decreased growth and yield. Bacillus species are used as biofertilizers and biopesticides for pearl millet and other crops to promote growth and yield. The use of Bacillus in saline soils has been beneficial to combat the negative effect of salinity on plant growth and yield. In this context, the present study emphasizes the use of two Bacillus species, i.e. Bacillus megaterium JR-12 and B. pumilus GN-5, which helped in alleviating the impact of salinity stress on the growth activities in salt-stressed pearl millet. Pearl millet seeds were treated with two strains, B. megaterium JR-12 and B.pumilus GN-5, individually and in combination under 50, 100 and 150 mM of sodium chloride stress. The treated plants showed higher plant height, biomass accumulation, and photosynthetic apparatus than the non-treated plants. Additionally, the treated plants showed increased osmoprotectant levels under salinity stress compared to control plants. The antioxidant enzyme content was improved post-inoculation, indicating the efficient stress-alleviating potential of both strains of Bacillus species. Moreover, inoculation of these microbes significantly increased plant growth attributes in plants treated with a combination of Bp-GN-5 + Bm-JR-12 and the reduction rates of plant growth were found to be alleviated to 9.12%, 20.30% and 33%, respectively. Overall, the results of the present study suggested that these microbes could have a higher potential to improve the productivity of pearl millet under salinity stress. [ABSTRACT FROM AUTHOR]

In the last decade, fresh-cut plants have become a more popular flavoring additive in food. It is important to find an effective method for ensuring the safety and quality of plant materials used as food additives. Ozonated water is being considered by the EFSA for approval as a cidal agent for plant protection. The objective of this study was to evaluate the effectiveness of ozonated water in improving the microbial safety of fresh-cut parsley leaves, with a particular focus on mesophilic and psychrotrophic bacteria and fungi. The yeasts and bacteria were identified with the MALDI-TOF MS system. Color changes on the surface of the parsley samples were measured in the CIE L*a*b trichromatic color model. The chemical composition of the essential oil was evaluated via gas chromatography with mass spectrometry (GCMS). The microbial level of the fresh leaves varied and depended on the season. The highest microbial levels were found in the leaves picked in the summer and autumn, at 104 to 106 CFU/g for fungi and 106 to 108 CFU/g for bacteria. Among the isolates with the highest isolation frequency, bacteria belonging to Pseudomonas fluorescens, Staphylococcus warneri, and Bacillus megaterium dominated. The dominant yeasts and molds were Candida sp., Rhodotorula sp., Cladosporium sp., and Fusarium sp. The conditions for water ozonation (ozone dose and time) were established for both mono- and mixed cultures. Time of 3 min, ozone content of 0.5, O3 mg/L or 1 min, and 1.5 mg of O3 mg/L were sufficient for a 90% reduction in the number of living microorganisms. Yeasts and bacteria were sensitive to ozone treatment, excluding P. fluorescens rods. The tested mold strains were the most resistant. However, it was noted that organic matter might reduce the decontamination effect. The effectiveness of ozonation was negatively influenced by organic compound content above 1%. Spectrophotometric measurements of parsley leaves after ozonation, especially after 3 min treatment at 1.5 O3 mg/L, revealed morphological changes. The CIELAB color space (L*a*b*) changed in the direction of lightness and yellowness; however, ΔE showed no statistically significant differences in comparison with the untreated leaves. In preliminary studies, no differences were noted in GLC-MS chromatograms for essential oils of parsley leaves before and after ozonation. The aroma of parsley treated with ozonated water was more intensely herbal than the control sample, probably due to the higher content of α and β phellandrene. The results of this study show that decontamination of parsley leaves by ozonated water containing 1.5 O3 mg/L in a closed 5 min process can effectively ensure the microbiological quality of fresh-cut parsley leaves. It can be concluded that ozone treatments in aqueous form appear to provide promising qualitative and quantitative results for the decontamination of this fresh-cut plant material. However, more work is necessary to study chemical and volatilome changes. Especially the sensory analyses should be conducted before and after ozone treatment. [ABSTRACT FROM AUTHOR]

The main goal of the present study was to evaluate the oxidation–reduction potential (ORP) on the production of poly(3-hydroxybutyrate) (P(3HB)) by Bacillus megaterium. Each microorganism has an optimal ORP range, and changes to the culture medium's ORP may redistribute the cell's metabolic flux, as such, the measurement and control of the ORP profile allows one to, in a way, manipulate the microbial metabolism, affecting the expression of certain enzymes and allowing for better control over the fermentative process. The ORP tests were carried out in a fermentation vessel coupled with an ORP probe, containing 1 L of mineral medium added with agroindustry byproducts (60% v/v of confectionery wastewater, and 40% v/v of rice parboiling water). The system's temperature was kept at 30 °C, with an agitation speed of 500 rpm. The vessel's airflow rate was controlled via a solenoid pump based on the ORP probe's data. Different ORP values were evaluated to verify their impact on biomass and polymer production. Cultures using OPR levels of 0 mV displayed the highest amounts of total biomass (5.00 g L−1) when compared to − 20 mV and − 40 mV (2.90 g L−1 and 0.53 g L−1, respectively). Similar results were also found for P(3HB)-to-biomass ratio, with polymer concentration being reduced when using ORP levels below 0 mV and with a maximum amount of polymer-to-biomass ratio of 69.87% after 48 h of culture. Furthermore, it was possible to observe that the culture's pH can also affect total biomass and polymer concentration, albeit to a lesser extent. Thus, when considering the data found during this study, it is possible to observe that ORP values can greatly impact B. megaterium cell's metabolism. Furthermore, the measurement and control of ORP levels may be an invaluable asset when trying to maximize polymer production under different culture conditions. [ABSTRACT FROM AUTHOR]

Two NIR-emitting donor-π-acceptor (D-π-A) type regioisomeric styryl pyridinium dyes (1a–1b) were synthesized and studied for their photophysical performance and environment sensitivity. The two regioisomers, 1a and 1b, exhibited interesting photophysical properties including, longer wavelength excitation (λex ≈ 530–560 nm), bright near-infrared emission (λem ≈ 690–720 nm), high-fluorescence quantum yields (ϕfl ≈ 0.24–0.72) large Stokes' shift (∆λ ≈ 150–240 nm) and high-environmental sensitivity. Probe's photophysical properties were studied in different environmental conditions such as polarity, viscosity, temperature, and concentration. Probes (1a–1b) exhibited noticeable changes in absorbance, emission and Stokes' shift while responding to the changes in physical environment. Probe 1b exhibited a significant bathochromic shift in optical spectra (∆λ ≈ 20–40 nm) compared to its isomer 1a, due to the regio-effect. Probes (1a–1b) exhibited an excellent ability to visualize bacteria (Bacillus megaterium, Escherichia coli), and yeast (Saccharomyces cerevisiae) via fluorescence microscopy. [ABSTRACT FROM AUTHOR]

Wild-type cytochrome P450 CYP102A1 from Bacillus megaterium is a highly efficient monooxygenase for the oxidation of long-chain fatty acids. The unique features of CYP102A1, such as high catalytic activity, expression yield, regio- and stereoselectivity, and self-sufficiency in electron transfer as a fusion protein, afford the requirements for an ideal biocatalyst. In the past three decades, remarkable progress has been made in engineering CYP102A1 for applications in drug discovery, biosynthesis, and biotechnology. The repertoire of engineered CYP102A1 variants has grown tremendously, whereas the substrate repertoire is avalanched to encompass alkanes, alkenes, aromatics, organic solvents, pharmaceuticals, drugs, and many more. In this article, we highlight the major advances in the past five years in our understanding of the structure and function of CYP102A1 and the methodologies used to engineer CYP102A1 for novel applications. The objective is to provide a succinct review of the latest developments with reference to the body of CYP102A1-related literature. [ABSTRACT FROM AUTHOR]

Plant growth-promoting rhizobacteria (PGPRs) are bacteria that colonize the plant roots. These beneficial bacteria have an influence on plant development through multiple mechanisms, such as nutrient availability, alleviating biotic and abiotic stress, and secrete phytohormones. Therefore, their inoculation constitutes a powerful tool towards sustainable agriculture and crop production. To understand plant-PGPRs interaction we present the classification of PGPR using machine learning and meta-learning classifiers namely Support Vector Machine (SVM), Kernel Logistic Regression (KLR), meta-SVM and meta-KLR to predict the presence of Bacillus megaterium inoculated in tomato root tissues using publicly available transcriptomic data. The original dataset presents 36 significantly differentially expressed genes. As the meta-KLR achieved near-optimal performance considering all the relevant metrics, this meta learner was afterwards used to identify the informative genes (IGs). The outcomes showed 157 IGs, being present all significantly differentially expressed genes previously identified. Among the IGs, 113 were identified as tomato genes, 5 as Bacillus subtilis proteins, 1 as Escherichia coli protein and 6 were unidentified. Then, a functional enrichment analysis of the tomato IGs showed 175 biological processes, 22 molecular functions and 20 KEGG pathways involved in B. megaterium–tomato interaction. Furthermore, the biological networks study of their Arabidopsis thaliana orthologous genes identified the co-expression, predicted interaction, shared protein domains and co-localization networks. [ABSTRACT FROM AUTHOR]

Proteolysis is the rate-limiting step in the mineralization of organic nitrogen into ammonium (NH4+) and thereby the ammonia (NH3) released during the composting. However, the dynamics of bacterial proteolytic communities related to NH3 emissions during the composting systems are mostly unknown. This study aimed to examine and compare the effects of hyperthermophilic pretreatment composting (HPC) and traditional composting (TC) methods on (i) the difference of NH3 loss and nitrogenous compounds; (ii) the dynamics of the proteolytic bacterial community involved in the proteolysis and (iii) the correlation between the proteolytic bacterial community, biophysiochemical characteristics and NH3 loss. Results revealed that the HPC decreased NH3 loss by 42% as compared to TC during 60-day composting period. This was accompanied with an inhibitory effect on protease activity in the HPC where the relative abundances of the proteolytic bacteria (Bacillus megaterium and Staphylococcus cohnii) were reduced significantly as compared to TC. Partial least-squares path modeling suggested that various physicochemical properties such as higher temperature as well as lower C/N ratio during composting played a dominant role in affecting the abundance of proteolytic bacteria, which may have been an important factor contributing to the lower NH3 loss in HPC. All these findings lead us to conclude that the HPC can significantly reduce NH3 loss by inhibiting the proteolytic bacteria and protease activity responsible for NH3 release. Keypoints: Hyperthermophilic pretreatment composting (HPC) resulted in lower NH3 emissions. This is attributed to the decline in proteolytic bacteria and protease activity. Proteolytic bacteria was controlled by physicochemical properties in HPC. [ABSTRACT FROM AUTHOR]

This study aims to find a moderate pullulanase for detergent industry. The pulY103B gene (2217 bp) from Bacillus megaterium Y103 was cloned and expressed in Escherichia coli. PulY103B contained four conserved regions of glycoside hydrolase family (GH) 13 and the typical sequence of type I pullulanase. The optimal reaction conditions of PulY103B were pH 6.5 and 40 °C. In addition, it remained stable below 40 °C and over 80% of activity was retained at pH ranging from 6.0 to 8.5. The best substrate for the enzyme was pullulan. Furthermore, it exhibited activity toward wheat starch (36.5%) and soluble starch (33.4%) but had no activity toward amylose and glycogen. Maltotriose and maltohexaose were major pullulan hydrolysis products. Soluble starch and amylopectin were mainly hydrolyzed into maltotetraose. These results indicated that PulY103B is a novel type I pullulanase with transglycosylation activity via formation of α-1,4-glucosidic linkages. Moreover, PulY103B was strongly stimulated by nonionic detergents [viz, Tween 20 (10%), Tween 80 (1%), Triton X-100 (20%)] and commercial liquid detergents (3.0 g/L). Wash performance tests demonstrated that the mixture of PulY103B and detergent removed starch-based stains better than using detergent alone (p < 0.05). Therefore, this pullulanase has big potential as a detergent additive. [ABSTRACT FROM AUTHOR]

Field research was conducted in Poland in 2019–2021 to determine the effect of microbial products and living mulches on grain yield and grain yield structure elements as well as the biological index of soil fertility (BIF) in spring barley grown in organic agriculture. Two factors were examined: I. microbial products: control (no treatment with microbial products), inoculation with phosphorus-releasing bacteria (Bacillus megaterium var. phosphaticum, Arthrobacter agilis), and co-inoculation (simultaneous inoculation) with phosphorus-releasing bacteria (Bacillus megaterium var. phosphaticum, Arthrobacter agilis) and nitrogen-fixing bacteria (Azospirillum lipoferum Br17, Azotobacter chroococcum); II. living mulch: control (no living mulch—spring barley grown in a pure stand), red clover, red clover and Italian ryegrass, and Italian ryegrass. The study results demonstrated that the highest grain yield at 4.5 t ha−1 with superior structure was produced by spring barley following co-inoculation with phosphorus-releasing bacteria (Bacillus megaterium var. phosphaticum, Arthrobacter agilis) and nitrogen-fixing bacteria (Azospirillum lipoferum Br17, Azotobacter chroococcum). The highest value of the biological index of soil fertility (BIF II) determined at the flowering stage was obtained in plots with spring barley cultivated with the living mulch of red clover mixed with Italian ryegrass or red clover following inoculation with phosphorus-releasing bacteria and nitrogen-fixing bacteria 6.9 and 5.7, respectively. [ABSTRACT FROM AUTHOR]