Maize Endophytic Plant Growth-Promoting Bacteria Peribacillus simplex Can Alleviate Plant Saline and Alkaline Stress.

Soil salinization is currently one of the main abiotic stresses that restrict plant growth. Plant endophytic bacteria can alleviate abiotic stress. The aim of the current study was to isolate, characterize, and assess the plant growth-promoting and saline and alkaline stress-alleviating traits of Peribacillus simplex M1 (P. simplex M1) isolates from maize. One endophytic bacterial isolate, named P. simplex M1, was selected from the roots of maize grown in saline-alkali soil. The P. simplex M1 genome sequence analysis of the bacteria with a length of 5.8 Mbp includes about 700 genes that promote growth and 16 antioxidant activity genes that alleviate saline and alkaline stress. P. simplex M1 can grow below 400 mM NaHCO3 on the LB culture medium; The isolate displayed multiple plant growth-stimulating features, such as nitrogen fixation, produced indole-3-acetic acid (IAA), and siderophore production. This isolate had a positive effect on the resistance to salt of maize in addition to the growth. P. simplex M1 significantly promoted seed germination by enhancing seed vigor in maize whether under normal growth or NaHCO3 stress conditions. The seeds with NaHCO3 treatment exhibited higher reactive oxygen species (ROS) levels than the maize in P. simplex M1 inoculant on maize. P. simplex M1 can colonize the roots of maize. The P. simplex M1 inoculant plant increased chlorophyll in leaves, stimulated root and leaf growth, increased the number of lateral roots and root dry weight, increased the length and width of the blades, and dry weight of the blades. The application of inoculants can significantly reduce the content of malondialdehyde (MDA) and increase the activity of plant antioxidant enzymes (Catalase (CAT), Superoxide Dismutase (SOD), and Peroxidase (POD)), which may thereby improve maize resistance to saline and alkaline stress. Conclusion: P. simplex M1 isolate belongs to plant growth-promoting bacteria by having high nitrogen concentration, indoleacetic acid (IAA), and siderophore, and reducing the content of ROS through the antioxidant system to alleviate salt alkali stress. This study presents the potential application of P. simplex M1 as a biological inoculant to promote plant growth and mitigate the saline and alkaline effects of maize and other crops.

Microbially Induced Calcium Carbonate Precipitation Using Lysinibacillus sp.: A Ureolytic Bacterium from Uttarakhand for Soil Stabilization.

Microbially induced calcium carbonate precipitation (MICP) is a soil remediation method that has emerged as a viable and long-term solution for enhancing soil mechanical qualities. The technique of MICP that has been extensively researched is urea hydrolysis, which occurs naturally in the environment by urease-producing bacteria as part of their fundamental metabolic processes. The objectives of the current study include screening and identifying native ureolytic bacteria from soil in Uttarakhand, optimizing growth factors for increased urease activity, and calcite precipitation by the bacteria using response surface methodology. Additionally, it was assessed how well the isolated bacteria in the medium biomineralized when using synthetic media and cheaper alternatives such as cow urine and eggshell as sources of urea and Ca2+, respectively. The isolated strain identified as Lysinibacillus sp. was found to be the very active strain after soil samples were screened for ureolytic bacteria. It was discovered that optimization studies with values of pH 8, urea concentration (0.8 M), inoculum concentration (3%), and incubation time (48 h) yielded a higher activity of 33.7 U/mL (threefold increase), and a higher calcium carbonate precipitation (enzyme activity: 10.96 U/mL, pH: 8.92, soluble Ca2⁺: 25.53 mM and insoluble Ca2⁺: 0.856 g). The calcite precipitation in broth media supplemented with ready-made substrates and alternative sources demonstrated a similar result of increased pH and ammonia release. Thus, the current study successfully paves the way for several possibilities to stabilize the slopy soils prone to landslides and erosion in Uttarakhand and pinpoint an economic approach through biomineralization.

[Deficiency in N-acetylglucosamine transport affects the sporulation process and increases the hemolytic activity of the S-layer protein in Lysinibacillus sphaericus ASB13052]. / La deficiencia en el transporte de N-acetilglucosamina en Lysinibacillus sphaericus ASB13052 afecta el proceso de esporulación e incrementa la actividad hemolítica de su S-layer.

Lysinibacillus sphaericus is a bacterium that, along with Bacillus thuringiensis var. israelensis, is considered the best biological insecticide for controlling mosquito larvae and an eco-friendly alternative to chemical insecticides. It depends on peptidic molecules such as N-acetylglucosamine to obtain carbon sources and possesses a phosphotransferase system (PTS) for their incorporation. Some strains carry S-layer proteins, whose involvement in metal retention and larvicidal activity against disease-carrying mosquitoes has been demonstrated. Alterations in the amino sugar incorporation system could affect the protein profile and functionality. Strain ASB13052 and the isogenic mutant in the ptsH gene, which is predominant in the PTS signaling pathway, were used in this study. For the first time, the presence of N-glycosylated S-layer proteins was confirmed in both strains, with a variation in their molecular weight pattern depending on the growth phase. In the exponential phase, an S-layer protein greater than 130 kDa was found in the ptsH mutant, which was absent in the wild-type strain. The mutant strain exhibited altered and incomplete low quality sporulation processes. Hemolysis analysis, associated with larvicidal activity, showed that the ptsH mutant has higher lytic efficiency, correlating with the high molecular weight protein. The results allow us to propose the potential effects that arise as a result of the absence of amino sugar transport on hemolytic activity, S-layer isoforms, and the role of N-acetylglucosamine in larvicidal activity.

Efficient bioremediation of multiple steroid hormones by halotolerant 17ß-hydroxysteroid dehydrogenase derived from moderately halophilic Pontibacillus chungwhensis HN14.

Steroid hormones exhibit potent endocrine disrupting activity and have been shown to disrupt the equilibrium of aquatic ecosystems and pose a threat to public health through their persistent and carcinogenic effects. Pontibacillus chungwhensis HN14, a moderately halophilic bacterium with the capacity to effectively degrade various polycyclic aromatic hydrocarbons and other organic pollutants, was previously isolated. Additionally, the strain HN14 showed strong environmental adaptability under various environmental stress conditions. In this study, the steroid degradation by strain HN14 was studied for the first time. We demonstrated that strain HN14 could degrade estradiol (E2) to maintain the growth of the strain and could convert E2 to estrone. Additionally, the efficient substrate degradation efficiency of P. chungwhensis HN14 under high salinity and high substrate concentration conditions was demonstrated. Furthermore, a 17ß-hydroxysteroid dehydrogenase, 17ß-HSD(HN14), was identified in strain HN14. Comparative analysis reveals that 17ß-HSD(HN14) shares approximately 38% sequence identity with 17ß-HSDx from Rhodococcus sp. P14. In addition, 100 µg of purified 17ß-HSD(HN14) could effectively convert about 40% of 0.25 mM of E2 within 1 h period, with an enzyme activity of 17.5 U/mg, and catalyze the dehydrogenation of E2 and testosterone at the C-17 position. The characterization of purified enzyme properties reveals that 17ß-HSD(HN14) exhibits exceptional structural robustness and enzymatic efficacy even under high salinity conditions of up to 20%. Overall, this study enhances our comprehension of steroid biodegradation in strain HN14 and contributes novel ideas and theoretical underpinnings for advancing bioremediation technologies targeting steroid pollution in high-saline environments.

Scavenger Receptor C1 Mediates Toxicity of Binary Toxin from Lysinibacillus sphaericus to Ag55 Cells.

Lysinibacillus sphaericus harboring Binary (BinA and BinB) toxins is highly toxic against Anopheles and Culex mosquito larvae. The Anopheles Ag55 cell line is a suitable model for investigating the mode of Bin toxin action. Based on the low-levels of α-glycosidase Agm3 mRNA in Ag55 cells and the absence of detectable Agm3 proteins, we hypothesized that a scavenger receptor could be mediating Bin cytotoxicity. Preliminary RNA interference knockdown of the expressed scavenger receptors, combined with Bin cytotoxicity assays, was conducted. The scavenger Receptor C1 (SCRC1) became the focus of this study, as a putative receptor for Bin toxins in Ag55 cells, and SCRBQ2 was selected as a negative control. Open reading frames encoding SCRC1 and SCRBQ2 were cloned and expressed in vitro, and polyclonal antibodies were prepared for immunological analyses. The RNAi silencing of SCRC1 and SCRBQ2 resulted in the successful knockdown of both SCRC1 and SCRBQ2 transcripts and protein levels. The cytolytic toxicity of Bin against Ag55 cells was severely reduced after the SCRC1-RNAi treatment. The phagocytic receptor protein SCRC1 mediates endocytosis of the Bin toxin into Ag55 cells, thereby facilitating its internal cytological activity. The results support a mechanism of the Bin toxin entering Ag55 cells, possibly via SCRC1-mediated endocytosis, and encourage investigations into how Bin is transferred from its bound form on the midgut epithelial cells into the epithelial endocytic system.

Harnessing the power of Neobacillus niacini AUMC-B524 for silver oxide nanoparticle synthesis: optimization, characterization, and bioactivity exploration.

BACKGROUND: Biotechnology provides a cost-effective way to produce nanomaterials such as silver oxide nanoparticles (Ag2ONPs), which have emerged as versatile entities with diverse applications. This study investigated the ability of endophytic bacteria to biosynthesize Ag2ONPs. RESULTS: A novel endophytic bacterial strain, Neobacillus niacini AUMC-B524, was isolated from Lycium shawii Roem. & Schult leaves and used to synthesize Ag2ONPS extracellularly. Plackett-Burman design and response surface approach was carried out to optimize the biosynthesis of Ag2ONPs (Bio-Ag2ONPs). Comprehensive characterization techniques, including UV-vis spectral analysis, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray diffraction, dynamic light scattering analysis, Raman microscopy, and energy dispersive X-ray analysis, confirmed the precise composition of the Ag2ONPS. Bio-Ag2ONPs were effective against multidrug-resistant wound pathogens, with minimum inhibitory concentrations (1-25 µg mL-1). Notably, Bio-Ag2ONPs demonstrated no cytotoxic effects on human skin fibroblasts (HSF) in vitro, while effectively suppressing the proliferation of human epidermoid skin carcinoma (A-431) cells, inducing apoptosis and modulating the key apoptotic genes including Bcl-2 associated X protein (Bax), B-cell lymphoma 2 (Bcl-2), Caspase-3 (Cas-3), and guardian of the genome (P53). CONCLUSIONS: These findings highlight the therapeutic potential of Bio-Ag2ONPs synthesized by endophytic N. niacini AUMC-B524, underscoring their antibacterial efficacy, anticancer activity, and biocompatibility, paving the way for novel therapeutic strategies.

Chromium (VI) removal by magnetite nanoparticles immobilized with extracellular polymeric substances extracted from Lysinibacillus sp. WH.

Magnetite nanoparticles (nano-Fe3O4) and nano-Fe3O4 immobilized with bacterial extracellular polymeric substances (EPSs) extracted from Lysinibacillus sp. WH (Fe3O4/bact) were comparatively studied for the removal of Cr (VI) ions from aqueous solution in batch study. The objectives were to explore the removal of Cr (VI) efficiency by nano-Fe3O4 and Fe3O4/bact under varying bacterial concentrations at a range of acidic pH. Results indicated that 150 ppm Cr (VI) could be effectively removed by 5 g/L of nano-Fe3O4 at pH 4, with the efficiency of 89.2 ± 12%. The equilibrium time, determined by a pseudo-second-order model (R2 = 0.9983), was after 5 h, indicating chemical adsorption. The Cr (VI) removal by the nano-Fe3O4 immobilized with bacterial EPS was effective and steady under a wide range of acidic conditions although bacterial EPS has an alkaline nature. Here, we are the first to demonstrate that Cr (VI) removal efficiency by different concentrations of EPS was not significantly different, suggesting EPS concentration is possibly not the most crucial factor to be optimized for Cr (VI) removal in the future. This study shows the potential application of nano-Fe3O4 immobilized with bacterial EPS for wastewater treatment. PRACTITIONER POINTS: The equilibrium time for magnetite nanoparticles to remove Cr (VI) is 5 h, suggesting chemical adsorption. The Cr (VI) removal efficiency of either magnetite nanoparticles or bacterial EPS is stable under a wide range of acidic conditions. Magnetite nanoparticles immobilized with bacterial EPS extracted from Lysinibacillus sp. WH has a potential application for Cr (VI) removal in wastewater.

Molecular identification and GC-MS analysis of a newly isolated novel bacterium (Lysinibacillus sp. VCRC B655) for mosquito control.

BACKGROUND: Mosquitoes are widespread globally and have contributed to transmitting pathogens to humans and the burden of vector-borne diseases. They are effectively controlled at their larval stages by biocontrol agents. Unravelling natural sources for microbial agents can lead us to novel potential candidates for managing mosquito-borne diseases. In the present study, an attempt was made to isolate a novel bacterium from the field-collected agricultural soil for larvicidal activity and promising bacterial metabolites for human healthcare. METHODS AND RESULTS: Field-collected soil samples from the Union territory of Puducherry, India, have been used as the source of bacteria. Isolate VCRC B655 belonging to the genus Lysinibacillus was identified by 16S rRNA gene sequencing and exhibited promising larvicidal activity against different mosquito species, including Culex (Cx.) quinquefasciatus, Anopheles (An.) stephensi, and Aedes (Ae.) aegypti. The lethal concentration (LC) of Lysinibacillus sp. VCRCB655 was observed to be high for Cx. quiquefasciatus: LC50 at 0.047 mg/l, LC90 at 0.086 mg/l, followed by An. stephensi and Ae. aegypti (LC50: 0.6952 mg/l and 0.795 mg/l) respectively. Additionally, metabolic profiling of the culture supernatant was carried out through Gas chromatography and Mass spectrophotometry (GC/MS) and identified 15 major secondary metabolites of different metabolic classes. Diketopiperazine (DKPs), notably pyro lo [1, 2-a] pyrazine1, 4-dione, are the abundant compounds reported for antioxidant activity, and an insecticide compound benzeneacetic acid was also identified. CONCLUSIONS: A new bacterial isolate, Lysinibacillus sp. VCRC B655 has been identified with significant larvicidal activity against mosquito larvae with no observed in non-target organisms. GC-MS analysis revealed diverse bioactive compounds with substantial biological applications. In conclusion, Lysinibacillus sp. VCRC B655 showed promise as an alternative biocontrol agent for mosquito vector control, with additional biological applications further enhancing its significance.

Fate, inducibility, and behavior of Latilactobacillus curvatus temperate phage TMW 1.591 P1 during sausage fermentation.

AIMS: Temperate phages insert their genome into the host's chromosome. As prophages, they remain latent in the genome until an induction event leads to lytic phage production. When this occurs in a starter culture that has been added to food fermentation, this can impair the fermentation success. This study aimed to analyze prophage inducibility in the Latilactobacillus curvatus TMW 1.591 strain during meat fermentation and investigate whether an induction signal before cryopreservation is maintained during storage and can lead to phage-induced lysis after culture activation. METHODS AND RESULTS: A prophage-free isogenic derivative of the model starter organism, L. curvatus TMW 1.591, was developed as a negative control (L. curvatus TMW 1.2406). Raw meat fermentation was performed with the wild-type (WT) and phage-cured strains. The WT strain produced high numbers of phages (5.2 ± 1.8 × 107 plaque-forming units g-1) in the meat batter. However, the prophage did not significantly affect the meat fermentation process. Induction experiments suggested an acidic environment as a potential trigger for prophage induction. Phage induction by ultraviolet light before strain cryopreservation remains functional for at least 10 weeks of storage. CONCLUSIONS: Intact prophages are active during meat fermentation. However, in this study, this has no measurable consequences for fermentation, suggesting a high resiliency of meat fermentation against phages. Inadequate handling of lysogenic starter strains, even before preservation, can lead to phage introduction into food fermentation and unintended host lysis.

The effect of extracellular polymeric substances on MICP solidifying rare earth slags and stabilizing Th and U.

Microbially induced carbonate precipitation (MICP) has been used to cure rare earth slags (RES) containing radionuclides (e.g. Th and U) and heavy metals with favorable results. However, the role of microbial extracellular polymeric substances (EPS) in MICP curing RES remains unclear. In this study, the EPS of Lysinibacillus sphaericus K-1 was extracted for the experiments of adsorption, inducing calcium carbonate (CaCO3) precipitation and curing of RES. The role of EPS in in MICP curing RES and stabilizing radionuclides and heavy metals was analyzed by evaluating the concentration and morphological distribution of radionuclides and heavy metals, and the compressive strength of the cured body. The results indicate that the adsorption efficiencies of EPS for Th (IV), U (VI), Cu2+, Pb2+, Zn2+, and Cd2+ were 44.83%, 45.83%, 53.7%, 61.3%, 42.1%, and 77.85%, respectively. The addition of EPS solution resulted in the formation of nanoscale spherical particles on the microorganism surface, which could act as an accumulating skeleton to facilitate the formation of CaCO3. After adding 20 mL of EPS solution during the curing process (Treat group), the maximum unconfined compressive strength (UCS) of the cured body reached 1.922 MPa, which was 12.13% higher than the CK group. The contents of exchangeable Th (IV) and U (VI) in the cured bodies of the Treat group decreased by 3.35% and 4.93%, respectively, compared with the CK group. Therefore, EPS enhances the effect of MICP curing RES and reduces the potential environmental problems that may be caused by radionuclides and heavy metals during the long-term sequestration of RES.

Comparative genomics reveals insights into the potential of Lysinibacillus irui as a plant growth promoter.

Members of the genus Lysinibacillus attract attention for their mosquitocidal, bioremediation, and plant growth-promoting abilities. Despite this interest, comprehensive studies focusing on genomic traits governing plant growth and stress resilience in this genus using whole-genome sequencing are still scarce. Therefore, we sequenced and compared the genomes of three endophytic Lysinibacillus irui strains isolated from Canary Island date palms with the ex-type strain IRB4-01. Overall, the genomes of these strains consist of a circular chromosome with an average size of 4.6 Mb and a GC content of 37.2%. Comparative analysis identified conserved gene clusters within the core genome involved in iron acquisition, phosphate solubilization, indole-3-acetic acid biosynthesis, and volatile compounds. In addition, genome analysis revealed the presence of genes encoding carbohydrate-active enzymes, and proteins that confer resistance to oxidative, osmotic, and salinity stresses. Furthermore, pathways of putative novel bacteriocins were identified in all genomes. This illustrates possible common plant growth-promoting traits shared among all strains of L. irui. Our findings highlight a rich repertoire of genes associated with plant lifestyles, suggesting significant potential for developing inoculants to enhance plant growth and resilience. This study is the first to provide insights into the overall genomic signatures and mechanisms of plant growth promotion and biocontrol in the genus Lysinibacillus. KEY POINTS: • Pioneer study in elucidating plant growth promoting in L. irui through comparative genomics. • Genome mining identified biosynthetic pathways of putative novel bacteriocins. • Future research directions to develop L. irui-based biofertilizers for sustainable agriculture.

Ethanologenic fermentation by Parageobacillus thermoglucosidasius with continuous hot microbubble gas-stripping.

The increased use of biofuels in place of fossil fuels is one strategy to support the transition to net-zero carbon emissions, particularly in transport applications. However, expansion of the use of 1st generation crops as feedstocks is unsustainable due to the conflict with food use. The use of the lignocellulosic fractions from plants and/or co-products from food production including food wastes could satisfy the demand for biofuels without affecting the use of land and the availability of food, but organisms which can readily ferment all the carbohydrates present in these feedstocks often suffer from more severe bioethanol inhibition effects than yeast. This paper demonstrates the potential of hot gas microbubbles to strip ethanol from a thermophilic fermentation process using Parageobacillus thermoglucosidasius TM333, thereby reducing product inhibition and allowing production to continue beyond the nominal toxic ethanol concentrations of ≤ 2% v/v. Using an experimental rig in which cells were grown in fed-batch cultures on sugars derived from waste bread, and the broth continuously cycled through a purpose-built microbubble stripping unit, it was shown that non/low-inhibitory dissolved ethanol concentrations could be maintained throughout, despite reaching productivities equivalent to 4.7% v/v dissolved ethanol. Ethanol recovered in the condensate was at a concentration appropriate for dewatering to be cost effective and not prohibitively energy intensive. This suggests that hot microbubble stripping could be a valuable technology for the continuous production of bioethanol from fermentation processes which suffer from product inhibition before reaching economically viable titres, which is typical of most thermophilic ethanologenic bacteria.

Enhancing spinach (Spinacia oleracea L.) resilience in pesticide-contaminated soil: Role of pesticide-tolerant Ciceribacter azotifigens and Serratia marcescens in root architecture, leaf gas exchange attributes and antioxidant response restoration.

This study unveils the detoxification potential of insecticide-tolerant plant beneficial bacteria (PBB), i.e., Ciceribacter azotifigens SF1 and Serratia marcescens SRB1, in spinach treated with fipronil (FIP), profenofos (PF) and chlorantraniliprole (CLP) insecticides. Increasing insecticide doses (25-400 µg kg-1 soil) significantly curtailed germination attributes and growth of spinach cultivated at both bench-scale and in greenhouse experiments. Profenofos at 400 µg kg-1 exhibited maximum inhibitory effects and reduced germination by 55%; root and shoot length by 78% and 81%, respectively; dry matter accumulation in roots and shoots by 79% and 62%, respectively; leaf number by 87% and leaf area by 56%. Insecticide application caused morphological distortion in root tips/surfaces, increased levels of oxidative stress, and cell death in spinach. Application of insecticide-tolerant SF1 and SRB1 strains relieved insecticide pressure resulting in overall improvement in growth and physiology of spinach grown under insecticide stress. Ciceribacter azotifigens improved germination rate (10%); root biomass (53%); shoot biomass (25%); leaf area (10%); Chl-a (45%), Chl-b (36%) and carotenoid (48%) contents of spinach at 25 µg CLP kg-1 soil. PBB inoculation reinvigorated the stressed spinach and modulated the synthesis of phytochemicals, proline, malondialdehyde (MDA), superoxide anions (O2•-), and hydrogen peroxide (H2O2). Scanning electron microscopy (SEM) revealed recovery in root tip morphology and stomatal openings on abaxial leaf surfaces of PBB-inoculated spinach grown with insecticides. Ciceribacter azotifigens inoculation significantly increased intrinsic water use efficiency, transpiration rate, vapor pressure deficit, intracellular CO2 concentration, photosynthetic rate, and stomatal conductance in spinach exposed to 25 µg FIP kg-1. Also, C. azotifigens and S. marcescens modulated the antioxidant defense systems of insecticide-treated spinach. Bacterial strains were strongly colonized to root surfaces of insecticide-stressed spinach seedlings as revealed under SEM. The identification of insecticide-tolerant PBBs such as C. azotifigens and S. marcescens hold the potential for alleviating abiotic stress to spinach, thereby fostering enhanced and safe production within polluted agroecosystems.

Oceanobacillus picturae alleviates cadmium stress and promotes growth in soybean seedlings.

Cadmium (Cd) is a heavy metal that significantly impacts human health and the environment. Microorganisms play a crucial role in reducing heavy metal stress in plants; however, the mechanisms by which microorganisms enhance plant tolerance to Cd stress and the interplay between plants and microorganisms under such stress remain unclear. In this study, Oceanobacillus picturae (O. picturae) was isolated for interaction with soybean seedlings under Cd stress. Results indicated that Cd treatment alone markedly inhibited soybean seedling growth. Conversely, inoculation with O. picturae significantly improved growth indices such as plant height, root length, and fresh weight, while also promoting recovery in soil physiological indicators and pH. Metabolomic and transcriptomic analyses identified 157 genes related to aspartic acid, cysteine, and flavonoid biosynthesis pathways. Sixty-three microbial species were significantly associated with metabolites in these pathways, including pathogenic, adversity-resistant, and bioconductive bacteria. This research experimentally demonstrates, for the first time, the growth-promoting effect of the O. picturae strain on soybean seedlings under non-stress conditions. It also highlights its role in enhancing root growth and reducing Cd accumulation in the roots under Cd stress. Additionally, through the utilization of untargeted metabolomics, metagenomics, and transcriptomics for a multi-omics analysis, we investigated the impact of O. picturae on the soil microbiome and its correlation with differential gene expression in plants. This innovative approach unveils the molecular mechanisms underlying O. picturae's promotion of root growth and adaptation to Cd stress.

Ureibacillus aquaedulcis sp. nov., isolated from freshwater well and reclassification of Lysinibacillus yapensis and Lysinibacillus antri as Ureibacillus yapensis comb. nov. and Ureibacillus antri comb. Nov.

A Gram-stain-positive aerobic, rod-shaped, spore-producing bacterium forming colonies with convex elevation and a smooth, intact margin was isolated from a freshwater sample collected from a well situated in an agricultural field. The 16S rRNA gene sequence of the isolated strain BA0131T showed the highest sequence similarity to Lysinibacillus yapensis ylb-03T (99.25%) followed by Ureibacillus chungkukjangi 2RL3-2T (98.91%) and U. sinduriensis BLB-1T (98.65%). The strain BA0131T was oxidase and catalase positive and urease negative. It also tested positive for esculin hydrolysis and reduction of potassium nitrate, unlike its phylogenetically closest relatives. The predominant fatty acids in strain BA0131T included were anteiso-C15:0, iso-C16:0, iso-C15:0, iso-C14:0 and the major polar lipids comprised were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The respiratory quinones identified in strain BA0131T were MK8 (H2) (major) and MK8 (minor). The strain BA0131T shared the lowest dDDH values with L. yapensis ylb-03T (21%) followed by U. chungkukjangi 2RL3-2T (24.2%) and U. sinduriensis BLB-1T (26.4%) suggesting a closer genetic relationship U. sinduriensis BLB-1T. The ANI percentage supported the close relatedness with U. sinduriensis BLB-1T (83.61%) followed by U. chungkukjangi 2RL3-2T (82.03%) and U. yapensis ylb-03T (79.57%). The core genome-based phylogeny constructed using over 13,704 amino acid positions and 92 core genes revealed the distinct phylogenetic position of strain BA0131T among the genus Ureibacillus. The distinct physiological, biochemical characteristics and genotypic relatedness data indicate the strain BA0131T represents a novel species of the genus Ureibacillus for which the name Ureibacillus aquaedulcis sp. nov. (Type strain, BA0131T = MCC 5284 = JCM 36475) is proposed. Additionally, based on extensive genomic and phylogenetic analyses, we propose reclassification of two species, L. yapensis and L. antri, as U. yapensis comb. nov. (Type strain, ylb-03T = JCM 32871T = MCCC 1A12698T) and U. antri (Type strain, SYSU K30002T = CGMCC 1.13504T = KCTC 33955T).

Genomic and functional evaluation of exopolysaccharide produced by Liquorilactobacillus mali t6-52: technological implications.

BACKGROUND: This study explores the biosynthesis, characteristics, and functional properties of exopolysaccharide produced by the strain Liquorilactobacillus mali T6-52. The strain demonstrated significant EPS production with a non-ropy phenotype. RESULTS: The genomic analysis unveiled genes associated with EPS biosynthesis, shedding light on the mechanism behind EPS production. These genes suggest a robust EPS production mechanism, providing insights into the strain's adaptability and ecological niche. Chemical composition analysis identified the EPS as a homopolysaccharide primarily composed of glucose, confirming its dextran nature. Furthermore, it demonstrated notable functional properties, including antioxidant activity, fat absorption capacity, and emulsifying activity. Moreover, the EPS displayed promising cryoprotective activities, showing notable performance comparable to standard cryoprotective agents. The EPS concentration also demonstrated significant freeze-drying protective effects, presenting it as a potential alternative cryoprotectant for bacterial storage. CONCLUSIONS: The functional properties of L. mali T6-52 EPS reveal promising opportunities across various industrial domains. The strain's safety profile, antioxidant prowess, and exceptional cryoprotective and freeze-drying characteristics position it as an asset in food processing and pharmaceuticals.

Seed endophytic bacterium Lysinibacillus sp. (ZM1) from maize (Zea mays L.) shapes its root architecture through modulation of auxin biosynthesis and nitrogen metabolism.

Seed endophytic bacteria have been shown to promote the growth and development of numerous plants. However, the underlying mechanism still needs to be better understood. The present study aims to investigate the role of a seed endophytic bacterium Lysinibacillus sp. (ZM1) in promoting plant growth and shaping the root architecture of maize seedlings. The study explores how bacteria-mediated auxin biosynthesis and nitrogen metabolism affect plant growth promotion and shape the root architecture of maize seedlings. The results demonstrate that ZM1 inoculation significantly enhances root length, root biomass, and the number of seminal roots in maize seedlings. Additionally, the treated seedlings exhibit increased shoot biomass and higher levels of photosynthetic pigments. Confocal laser scanning microscopy (CLSM) analysis revealed extensive colonization of ZM1 on root hairs, as well as in the cortical and stellar regions of the root. Furthermore, LC-MS analysis demonstrated elevated auxin content in the roots of the ZM1 treated maize seedlings compared to the uninoculated control. Inoculation with ZM1 significantly increased the levels of endogenous ammonium content, GS, and GOGAT enzyme activities in the roots of treated maize seedlings compared to the control, indicating enhanced nitrogen metabolism. Furthermore, inoculation of bacteria under nitrogen-deficient conditions enhanced plant growth, as evidenced by increased root shoot length, fresh and dry weights, average number of seminal roots, and content of photosynthetic pigments. Transcript analysis indicated upregulation of auxin biosynthetic genes, along with genes involved in nitrogen metabolism at different time points in roots of ZM1-treated maize seedlings. Collectively, our findings highlight the positive impact of Lysinibacillus sp. ZM1 inoculation on maize seeds by improving root architecture through modulation of auxin biosynthesis and affecting various nitrogen metabolism related parameters. These findings provide valuable insights into the potential utilization of seed endophytic bacteria as biofertilizers to enhance plant growth and yield in nutrient deficient soils.

Overcoming the inhibitory effects of urea to improve the kinetics of microbial-induced calcium carbonate precipitation (MICCP) by Lysinibacillus sphaericus strain MB284.

Among different microbial-induced calcium carbonate precipitation (MICCP) mechanisms utilized for biomineralization, ureolysis leads to the greatest yields of calcium carbonate. Unfortunately, it is reported that urea-induced growth inhibition can delay urea hydrolysis but it is not clear how this affects MICCP kinetics. This study investigated the impact of urea addition on the MICCP performance of Lysinibacillus sphaericus MB284 not previously grown on urea (thereafter named bio-agents), compared with those previously cultured in urea-rich media (20 g/L) (hereafter named bio-agents+ or bio-agents-plus). While it was discovered that initial urea concentrations exceeding 3 g/L temporarily hindered cell growth and MICCP reactions for bio-agents, employing bio-agents+ accelerated the initiation of bacterial growth by 33% and led to a 1.46-fold increase in the initial yield of calcium carbonate in media containing 20 g/L of urea. The improved tolerance of bio-agents+ to urea is attributed to the presence of pre-produced endogenous urease, which serves to reduce the initial urea concentration, alleviate growth inhibition, and expedite biomineralization. Notably, elevating the initial concentration of bio-agents+ from OD600 of 0.01 to 1, housing a higher content of endogenous urease, accelerated the initiation of MICCP reactions and boosted the ultimate yield of biomineralization by 2.6 times while the media was supplemented with 20 g/L of urea. These results elucidate the advantages of employing bio-agents+ with higher initial cell concentrations to successfully mitigate the temporary inhibitory effects of urea on biomineralization kinetics, offering a promising strategy for accelerating the production of calcium carbonate for applications like bio self-healing of concrete.

Conversion of metal-enriched magnetite mine tailings into suitable soil for vegetation by phytoremediation process with Bougainvillaea glabra under the influence of Thiobacillus ferroxidance.

Magnetite mining is a significant contributor to land deterioration as well as HM-based soil contamination. The characteristics of magnetite mine tailing were examined in the present study, in addition to the positive and sustainable restoration strategy with Bougainvillaea glabra under the influence of Thiobacillus ferroxidance. The traits of test soil analysis findings demonstrated that the majority of the parameters exceeded the allowable limits (For instance: HMs such as Cr, Cu, Zn, Pb, Fe, and Co were found to be 208 ± 2.3, 131.43 ± 1.6, 185.41 ± 3.3, 312 ± 5.11, 956 ± 5.3, and 26.89 ± 2.43 mg kg-1 respectively). T. ferroxidance exhibited impressive HMs tolerance for as much as 800 g mL-1 concentrations of Cr, Cu, Zn, Pb, Fe, and Co. To prevent HMs toxic effects, the HMs contents in test soil were decreased by diluting with normal soil in the ratios of Ex-3 and Ex-2. A typical greenhouse study was carried out to assess the phytoremediation ability of B. glabra across six setups for experiments (Ex-1 to Ex-6). According to the findings of this research, the HMs tolerant T. ferroxidance from Ex-3 and Ex-2 had an outstanding impact on the growth, biomolecules level (such as chlorophylls: 65.84 & 41.1 mg g-1, proteins: 165.1 & 151.1 mg g-1, as well as carbohydrates: 227.4 & 159.3 mg g-1) as well as phytoremediation potential of B. glabra on magnetite mine soil. These findings indicated that a mixture of B. glabra as well as T. ferroxidance might serve as a valuable sustainable agent for removing HMs from contaminated soil.

Parageobacillus thermoglucosidasius as an emerging thermophilic cell factory.

Parageobacillus thermoglucosidasius is a thermophilic and facultatively anaerobic microbe, which is emerging as one of the most promising thermophilic model organisms for metabolic engineering. The use of thermophilic microorganisms for industrial bioprocesses provides the advantages of increased reaction rates and reduced cooling costs for bioreactors compared to their mesophilic counterparts. Moreover, it enables starch or lignocellulose degradation and fermentation to occur at the same temperature in a Simultaneous Saccharification and Fermentation (SSF) or Consolidated Bioprocessing (CBP) approach. Its natural hemicellulolytic capabilities and its ability to convert CO to metabolic energy make P. thermoglucosidasius a potentially attractive host for bio-based processes. It can effectively degrade hemicellulose due to a number of hydrolytic enzymes, carbohydrate transporters, and regulatory elements coded from a genomic cluster named Hemicellulose Utilization (HUS) locus. The growing availability of effective genetic engineering tools in P. thermoglucosidasius further starts to open up its potential as a versatile thermophilic cell factory. A number of strain engineering examples showcasing the potential of P. thermoglucosidasius as a microbial chassis for the production of bulk and fine chemicals are presented along with current research bottlenecks. Ultimately, this review provides a holistic overview of the distinct metabolic characteristics of P. thermoglucosidasius and discusses research focused on expanding the native metabolic boundaries for the development of industrially relevant strains.