Genus Bacillus Research Articles

Heterologous expression of calcium-independent mesophilic α-amylase from Priestia megaterium: Immobilization on genipin-modified multi-walled carbon nanotubes and silica supports to enhance thermostability and catalytic activity.

α-Amylases, constituting a significant share of the enzyme market, are mainly synthesized by the genus Bacillus. Enzymes tailored for specific industrial applications are needed to meet the growing demand across a range of industries, and thus finding new amylases and optimizing the ones that already exist are extremely important. This study reports the successful expression, characterization and immobilization of P. megaterium α-amylase (PmAmy) in E. coli protein expression systems. The recombinant PmAmy has a molecular weight of 56kDa and its in silico predicted model structure presents a monomer composed of three domains, like most amylases. Regarding long-term storage, PmAmy remained 60% active after 6weeks of storage at -20 and -80°C indicating its stable storage at low temperatures. PmAmy was found to be Ca2+ ion-independent for both catalytic activity and thermostability while Mn2+ enhanced activity in a concentration-dependent manner. The optimum characteristic working conditions of PmAmy were measured as pH 7.0 and 40°C. Immobilizing PmAmy significantly improved its thermal stability, increasing its resistance to thermal denaturation by at least 4.1-fold. Kinetic analyses revealed that the KM and Vmax values of free PmAmy were 0.1mg mL-1 and 556 U mg-1, respectively while immobilization resulted in an increase for both the KM and Vmax values. Kinetic analysis revealed enhanced activity for the Ca2+-independent immobilized enzyme, making it suitable for industrial applications particularly starch processing requiring moderate thermostability without the need for Ca2+ ions.

Enhancing bioremediation of diesel/biodiesel blend (B20) impacted sites using in situ bioreactors: A nature-based solution for sustainable groundwater management

The rise of biodiesel content in diesel/biodiesel blends as a viable alternative to traditional diesel fuel presents several advantages, particularly in terms of reduced emissions of pollutants like carbon monoxide (CO), hydrocarbons (HC), and smoke. However, the increased production and utilization of biodiesel raise concerns about potential environmental impacts, such as groundwater pollution. This has led to a growing need for sustainable and effective bioremediation techniques to address these issues and ensure the safe closure of contaminated sites in accordance with environmental regulatory criteria. Two experimental areas contaminated with B20 (80% diesel and 20% biodiesel v/v) to evaluate ammonium acetate biostimulation (B20_BAA) and natural source zone depletion (B20_NSZD) as remediation strategies were monitored for 10 and 12 years, respectively. Although the benzene half-life was 1.49 and 4.08 years, respectively, hydrocarbon concentrations remained above the maximum contaminant level (MCL) allowed in Brazil for groundwater, requiring additional technologies for site cleanup. Then, two pilot-scale airlift bioreactors were employed as nature-based solutions (NbS) to reduce the concentration of persistent contaminants for site closure. Indeed, concentrations of benzene and 2-methylnaphthalene decreased significantly after the bioreactors began operation, reaching values below their respective MCL. 16S rRNA gene sequencing showed a beneficial response of microbial communities composed of Massilia, Burkholderia-Caballeronia-Paraburkholderia, Mycobacterium and Bacillus genus involved in hydrocarbons aerobic biodegradation. Moreover, predicted functional genes analysis demonstrated that the relative abundances of key aerobic degradation pathways for benzene and 2-methylnaphthalene increased, supporting the hypothesis that the NbS stimulated the hydrocarbons biodegradation. These findings demonstrated that combining different nature-based solutions (NbS) can effectively remediate petroleum hydrocarbons in contaminated groundwater through geochemical characteristics and exploration of indigenous microorganisms. To the best of the authors’ knowledge, this is the first study to employ bioreactors to treat B20-contaminated groundwater at a field scale.

Engineering of acyl ligase domain in non-ribosomal peptide synthetases to change fatty acid moieties of lipopeptides

Cyclic lipopeptides (CLPs) produced by the genus Bacillus are amphiphiles composed of hydrophilic amino acid and hydrophobic fatty acid moieties and are biosynthesised by non-ribosomal peptide synthetases (NRPSs). CLPs are produced as a mixture of homologues with different fatty acid moieties, whose length affects CLP activity. Iturin family lipopeptides are a family of CLPs comprising cyclic heptapeptides and β-amino fatty acids and have antimicrobial activity. There is little research on how the length of the fatty acid moiety of iturin family lipopeptides is determined. Here, we demonstrated that the acyl ligase (AL) domain determines the length of the fatty acid moiety in vivo. In addition, enzyme assays revealed how mutations in the substrate-binding pocket of the AL domain affected substrate specificity in vitro. Our findings have implications for the design of fatty acyl moieties for CLP synthesis using NRPS.

To study the effect of probiotic strains of the genus Bacillus on the state of internal organs and humoral immunity of Coturnix coturnix and Mus musculus

To study the effect of probiotic strains of the genus Bacillus on the state of internal organs and humoral immunity of Coturnix coturnix and Mus musculus

Biochemical and enzymatic alterations of watermelon associated with irrigation management and inoculation with Rhizobacteria

Water stress has caused major losses in the agricultural productivity of crops, inducing the search for alternatives for sustainable cultivation. In this context, the objective of this study was to evaluate the tolerance of watermelon under water stress, inoculated with bacterial strains of the genus Bacillus spp., regarding the biochemical and enzymatic variables in the flowering stage. A randomized block design was adopted in a split-plot 4x4 factorial scheme, with plots consisting of four levels of soil water availability (40%, 60%, 80% and 100% of field capacity - FC) and subplots consisting of four inoculations (Negative Control (NC); XX6.9 bacteria; P6.2 bacteria; MIX – co-inoculation of XX6.9 and P6.2 bacteria), with five replicates. XX6.9 bacteria and NC were the treatments most affected by severe water stress, since at the soil water availability (SWA) level of 40% FC they showed high contents of the oxidative marker (MDA) and proline. Although the inoculation with XX6.9 bacteria promoted a higher content of osmoregulators such as proteins, total soluble sugars and reducing sugars, it was not enough to attenuate the effects of water deficit. On the other hand, treatments with P6.2 bacteria and MIX of bacteria showed reduced levels of MDA at the SWA level of 40% FC, accompanied by high enzymatic activity of POD and CAT, which may contribute to the tolerance of the watermelon crop to water stress.

Discovery and mechanistic exploration of promiscuous xylosyltransferase based on protein engineering.

Glycosylation is an effective means to alter the structure and properties of plant compounds, influencing the pharmacological activity of natural products (NPs) to obtain highly active NPs. In nature, glucosides are the most widely distributed, while other glycosides such as xylosides are less common and present in lower quantities. This is due to the scarcity of xylosyltransferases with substrate promiscuity in nature, and the modification of their catalytic function is also quite challenging. In this study, we first performed a phylogenetic analysis of reported UDP-glycosyltransferases (UGTs) of plant and microbiological origin and identified a unique motif region from the UGTs of the Bacillus genus, which may be responsible for the broad sugar donor catalytic activity of the UGTs in the Bacillus genus. Then, utilizing protein engineering techniques, we have evolved a xylosyltransferase M3-2, which exhibited high substrate promiscuity, sugar donor promiscuity, and site selectivity, enabling the synthesis of a variety of O-glycosides. In addition, another mutant M3-1 has been engineered to alter the sugar donor specificity of the UGT, enabling the switch from UDP-Glc donor to UDP-Xyl. The improved enzymatic activity is likely attributed to stable hydrophobic interactions and hydrogen bonding interactions between the enzyme and the substrate. In order to synthesize xylosylated products more economically and efficiently, an in vitro synthetic pathway that utilizes NPs and inexpensive glucuronic acid as starting materials was designed. Through this pathway, we successfully synthesized a variety of unnatural xylosylated products belonging to O-glycosides, one of which 10a possesses excellent anti-inflammatory activity. We anticipate that this work will contribute to the future discovery and industrial production of unnatural glycosides.

Bacteria of the genus Bacillus are effective in reducing phosphorus in aquaculture pond sediments

Biological products are commonly used in aquaculture to treat waste generated during production. In this context, the objective of the present study was to evaluate the efficiency of Bacillus bacteria in treating sediment from an aquaculture pond. For this purpose, 15 experimental units were used, arranged in a completely randomized design with five treatments and three replicates. The treatments were determined by different doses of a commercial bioremediatory composed of Bacillus subtilis, B. licheniformis, B. amyloliquefaciens, and B. pumilus, with a concentration of 3.5 x 109 UFC/g, at doses of 100, 200, 300, 400 and 500 g/ha. In each experimental unit, 5 cm of sediment from fishpond was added, followed by the addition of 15 liters of water. The bioremediator doses were added to the water in each experimental unit, and the study lasted for 15 days. Water and sediment chemical analyses were performed before and after the experimental period. The data were subjected to analysis of variance, followed by Tukey’s test at a 5% significance level for mean comparison. No significant influence of the treatments was observed on water quality parameters, pH, effective cation exchange capacity, or base saturation of the sediment (p > 0,05). There was fluctuation in the organic matter percentage of the sediment, with the lowest value observed for the 300 g/ha (p < 0.05). The 400 g/ha dosage of the product resulted in a 60% reduction in sediment phosphorus. In conclusion, Bacillus bacteria, through the commercial bioremediatory, are efficient in reducing organic matter and phosphorus in fishpond sediments, and their action does not interfere with soil pH, cation exchange capacity, or base saturation.

Harnessing Bacillus Species for Antibiotic Discovery: A Review

The genus Bacillus is a group of rod-shaped, gram-positive bacteria known for their vast potential of the production of antibiotics. This review examines the potentials of various Bacillus species in the production of antibiotics. There is a global threat of antimicrobial resistance and have spurred the need in scientific research for novel antibiotics and Bacillus species offers a ray of hope in the discovery of novel antibiotics. Notable among the antibiotics produced by Bacillus species include fengycin, gramicidin, iturin, polymyxin, subtilin, difficidin, surfactin, megacin, lichenysin, bacitracin, cerein, pumilicin, circulin, each with greater stability and wide spectrum of activity against gram-positive as well as gram-negative bacteria, fungi. This review highlights the various Bacillus species with antibiotics producing abilities such as B. subtilis, B. polymyxa, B. cereus, B. pumilus, B. megaterium, B. circulans, the antibiotics produced by these Bacillus species, mechanisms of actions of these antibiotics, potential application in medicine, agriculture, biotechnology and industry. Bacillus species with antibiotics producing potentials can be applied in combatting the threat posed by antibiotic-resistant pathogens as well as multi-drug-resistant pathogens.

The Effect of Storage Time of Water Hyacinth Liquid Organic Fertilizer on Microorganism Viability and Potency

The quality of biological organic fertilizer is determined by the viability of microorganisms during storage until the fertilizer is applied to the field. The purpose of this study was to determine the effect of length of storage of biological organic fertilizer on the viability of microorganisms, and identify the types of microorganisms that can survive in several storage periods and their potential. The research was conducted at the Payakumbuh State Agricultural Polytechnic Screenhouse from September to November 2024 using a non-factorial Completely Randomized Design (CRD) with five treatments and five replications. The treatment of storage duration of biological organic fertilizer includes: T1 = 0 days storage time, T2 = 7 days storage time, T3 = 14 days storage time, 21 days storage time, and 28 days storage time. The results showed that the best storage length for bacterial viability was from 0 to 14 days after fermentation with a bacterial population of 1.0,107-3.3,107 CFU/ml and a fungal population of <10-1.4,102 CFU/ml. Seven potential and multifunctional bacterial isolates were found, B. altitudinis, Bacillus cf. zanthoxylli, Bacillus cereus, Pseudomonas aeruginosa, Pseufomonas. flexibilis, Pseudomonas cf. pharmacofabricae, and Ectopseudomonas mendocina. All bacterial isolates were able to produce IAA hormone with concentrations between 0.0039-0.0057 µg/ml. Bacterial species that have high viability in water hyacinth POH are bacteria from the genera Bacillus spp. and Pseudomonas spp.

Soil microorganism biodiversity in pule (Alostonia scholarus L.) and candlenut trees (Aleurites moluccana L.) at Wijaya Kusuma Campus Surabaya

A beautiful and fresh environment is visible with lush trees that illustrate the level of soil fertility and the diversity of microbes in it. Plant growth and development are influenced by the abundance of soil microbes, which reflect soil fertility and soil biological properties. Wijaya Kusuma Campus Surabaya is a campus whose slogan is Keluruhuran Jiwa Berbenah Lingkungan (Keji Beling) as a form of concern for the environment and the desire to create a healthy environment, it is necessary to explore the existence of potential microbes from the roots of trees in the campus environment. The purpose of this study was to determine the number and type of soil microbial isolates isolated from the rhizosphere of pule (Alostonia scholarus L.) and candlenut (Aleurites moluccana L.) trees on the Wijaya Kusuma Campus Surabaya. This research is exploratory descriptive qualitative research. Research methods include microbial isolation in the rhizosphere of pule and candlenut plants, macroscopic and microscopic characterization of microbes, KOH test, and catalase test. Data were analyzed descriptively describing the number and type of isolates. The results of the study concluded that the isolation results from the Pule tree obtained 12 colonies of fungi and the Candlenut tree obtained 6 colonies. The genus found were Aspergillus flavus, Aspergillus niger, Fusarium sp., Penicillium sp. In addition, 27 bacterial colonies were found on the pule tree and 23 bacterial colonies on the candlenut tree, namely the genus Bacillus sp. The isolate results obtained can be used as microbial observation material in biology learning.

Evaluation of Soil Beneficial Bacteria as Plant Growth Enhancer and Biocontrol Agents

The use of soil beneficial bacteria, particularly plant growth-promoting rhizobacteria (PGPR), provides an eco-friendly alternative to synthetic agrochemicals in sustainable agriculture. This study aimed to isolate and characterize soil bacterial isolates from the rhizosphere of cabbage cultivation areas in Cameron Highlands, Malaysia, and evaluate their potential as PGPR and biocontrol agents. A total of 42 bacterial isolates were obtained, of which 15 were selected for detailed screening. Morphological and molecular characterization using 16S rDNA sequencing identified species from the genera Bacillus, Pseudomonas, and Serratia. These isolates exhibited key plant growth-promoting traits, including nitrogen fixation, phosphate solubilization, and potassium solubilization. Notably, isolates S9 and S30 demonstrated both plant growth-promoting and antibacterial activities against Xanthomonas campestris, a major pathogen of cabbage. Meanwhile, isolates S16 and S36, although lacking antibacterial activity, showed strong growth-promoting capabilities. These findings highlight the potential of native soil beneficial bacteria as biofertilizers and biocontrol agents, contributing to sustainable agricultural practices by reducing reliance on chemical fertilizers and pesticides. Future research should focus on field trials to validate their efficacy under diverse environmental conditions.

Spatial Variation of Salmonella Bacteria for Plants in the Environment of Mishkab District Center

This research included the detection of knowledge of the numbers of salmonella bacteria species in the plants of the Mishkab district environment for four seasons and the knowledge of the variation in their numbers for each season and the salmonella of the genus Bacillus negative color in the Gram dye belonging to the family Enterobacteriaceae. They are strong bacteria that are found everywhere and can survive for several weeks in a dry environment and several months in water and moist soil and then move to the plant from the soil and water polluted by many sources. The main reason for the growth and spread of these bacteria is the feces of humans and animals. When the appropriate conditions for these bacteria are available, they help them spread and move to other places in the environment. Four maps were drawn for spatial modeling of salmonella bacteria in plants. Samples were taken for 30 important sites where most of the plants on which the population depends depend on food in the first place, such as vegetables, fruits and grain crops, in addition to natural plants that are spread in most parts and conduct analysis in various scientific laboratories.

Isolation and characterization of Bacillus sp. HSY32 and its toxin gene for potential biological control of plant parasitic nematode

Plant parasitic nematodes (PPNs) cause significant damage to crop production worldwide, leading to substantial economic losses. Conventional chemical nematicides are effective but frequently associated with environmental and health hazards. In response, biological control methods, particularly the use of microbial pesticides, have emerged as a sustainable and effective alternative. This study focuses on the isolation and characterization of Bacillus sp. HSY32, a bacterial strain with nematicidal properties, from a tropical rainforest soil sample in Hainan, China. Soil samples were screened for nematicidal activity, which led to the identification of the strain HSY32. Detailed observations using optical and scanning electron microscopy (SEM) revealed that HSY32 forms spores and parasporal crystal structures, which are typically associated with nematicidal Bacillus species. Genomic analysis of HSY32 showed that its genome spans 6,711,949 base pairs and contains 7915 predicted genes, with an average GC content of 35.4%. Phylogenetic analysis, utilizing 16S rRNA sequences and average nucleotide identity (ANI), established that HSY32 is closely related to Bacillus mobilis, a known species within the Bacillus genus. Further genomic analysis using local BLAST identified several toxin genes with high similarity to known nematicidal genes, including cry4Ba, cry50Ba, app6Ba, cry70Bb, and tpp36Aa. To confirm the functionality of these toxin genes, they were cloned into pET-30a expression vectors and expressed in E. coli BL21 (DE3) cells. Among the expressed proteins, the Cry4Ba-like protein, with a molecular weight of approximately 110 kDa, was found to exhibit significant nematicidal activity in bioassays. This protein demonstrated the ability to kill or inhibit the growth of PPNs, indicating its potential as a biological control agent. The successful isolation of Bacillus strain HSY32 and the identification of its novel Cry4-like toxin gene represent a significant advancement in the field of biological control of plant parasitic nematodes. The nematicidal activity of the Cry4Ba-like protein highlights the potential of HSY32 as a source of new biopesticides. Further studies are required to enhance the production and application of these biocontrol agents in agriculture, paving the way for more sustainable and eco-friendly methods to control PPNs.Graphical

Toxicity And Antioxidant Activities of Endophytic Bacteria from Butterfly Pea (<i>Clitoria ternatea</i> Linn.)

Endophytic bacteria are bacteria that live in healthy plant tissues without causing damage. Several studies have reported that endophytic bacteria can produce active compounds similar to those secreted by their host and which potentially have medicinal value. Butterfly pea (Clitoria ternatea L.) was noted to be able to produce antioxidants and have toxicity potential from its compounds. Therefore, endophytic bacteria from butterfly pea have great potential to have antioxidant activity along with evaluating the toxicity level of the selected bacteria. This study aimed to determine the number of isolates, to characterize, and test the toxicity and antioxidant activities of endophytic bacteria from butterfly pea. Toxicity level was tested using the Brine Shrimp Lethality Test (BSLT) method while levels of antioxidants were tested using the DPPH (1,1-diphenyl-2-picrylhydrazyl) method. A total of fifteen endophytic bacteria were obtained and successfully purified. Based on the morphological observations, Gram staining, and biochemical test results, isolate EBT13 was determined to belong to the genus Bacillus. Isolate EBT13 was categorized as highly toxic, with the highest toxicity value with other bacterial isolates with an LC50 of 84 ppm and antioxidant activity with an IC50 value of 44.32 ppm. Based on the phylogenetic tree of 16S rRNA gene analysis, EBT13 belongs to the genus Bacillus, it forms a sister group with Bacillus pumilus with a bootstrap value of 100%. This study advances our knowledge of plant-microbe interactions by identifying a highly toxic, antioxidant-producing strain of bacteria of butterfly pea. The results have significance for the development of cytotoxic chemicals and natural antioxidants, which could advance biotechnological research and boost therapeutic purpose.

Potential of Local Microorganisms Solution from Chicken Manure as a Bioactivator in Liquid Waste Treatment from the Fish Cracker Processing Industry

The wastewater produced by traditional food industry is a source of problem due to its high levels of organic compounds pollutant that can increase the level of chemical oxygen demand (COD) and biological oxygen demand (BOD) values that exceed the established wastewater quality standard thresholds. The difficulty in removing high concentrations of organic material through conventional waste treatment necessitates the use of special treatment methods using local microorganisms’ solution as bioactivators to accelerate the decomposition of organic compounds. This research aims to identify bacteria in local microorganisms’ solution with potential applications in reducing organic compounds by its enzymatic activities. Based on the research results, among the 42 isolates examined, six isolates demonstrated the ability to hydrolyze starch, protein and fat based on qualitative tests. These isolates belong to the genus Bacillus based on partial sequencing of 16S rRNA gene. The qualitative tests confirmed the potential of these isolates as they exhibited enzymatic activities that showed potential to reduce organic compounds.

Ecological Niches of Bacillus Species and their Multifaceted Mechanisms in Combatting Plant Pathogens

The Bacillus genus, an integral member of the Firmicutes phylum, is characterized by its rod-shaped structure and widespread presence in diverse ecosystems. Known for its resilience, Bacillus thrives in various environments, making it a versatile agent in agriculture. Several Bacillus species serve as biocontrol agents, effectively managing fungal and bacterial plant diseases. Their efficacy stems from a range of biochemical and metabolic actions, including the production of siderophores that suppress phytopathogens and promote plant growth. Bacillus spp. produce hydrolytic enzymes such as chitinases, glucanases, proteases, and cellulases, which degrade pathogen cell components, leading to cellular collapse. Additionally, Bacillus secretes antimicrobial compounds like bacillomycin, fengycin, iturin, surfactin, and difficidin, targeting multiple plant pathogens. The production of volatile antimicrobial compounds further enhances their biocontrol potential by inhibiting microbial growth and reproduction. Moreover, Bacillus plays a vital role in activating plant defense mechanisms, including Induced Systemic Resistance (ISR). Through the production of elicitor compounds, Bacillus triggers the jasmonic acid signaling pathway on host plant, fortifying the plant's biochemical and physical barriers against pathogen invasion. These multifaceted attributes position Bacillus as a promising tool for sustainable plant disease management and enhanced crop health.

Exploring IAA biosynthesis and plant growth promotion mechanism for tomato root endophytes with incomplete IAA synthesis pathways

Exploring indoleacetic acid (IAA) biosynthesis pathways of plant growth promoting bacteria and their ability to synthesize IAA is crucial for understanding the promotion mechanism and for developing more efficient microbial fertilizer. In this study, 118 bacterial endophytic strains were isolated from tomato root and 68 isolates were identified as members of Bacillus and Pseudomonas genus. After screening abilities to synthesize IAA in vitro and promote plant growth for these identified Bacillus and Pseudomonas strains, 7 endophytic strains Bacillus sp. Y_21, B. paramycoides Y_29, B. albus Y_96, B. cereus Y_121, P. plecoglossicida Y_157, Bacillus sp. Y_165 and B. aryabhattai Y_170 strains showed a significant promotion role on wheat root or leaf, including 4 endophytic strains with the potential ability to utilize intermediate metabolites, such as tryptamine and indole acetamide, to produce IAA. Genomic sequencing analysis for selected representative plant growth promoting endophytes showed that IAA-producing bacteria B. cereus mr31 and P. putida Y_166 separately harbored a complete indoleacetamide (IAM) and complete tryptamine (TAM) pathway; whereas, Bacillus sp. Y_165 and B. aryabhattai Y_170, two strains producing IAA not using tryptophan but with indole-3-acetamide, had an incomplete IAM pathway. Fermentation experiments of three genome-sequenced strains using wheat or tomato root extracts as substrate, and combining with UHPLC–MS/MS analysis for wheat root extracts, demonstrated that Bacillus sp. Y_165 strain might produce IAA by using the plant-derived indole-3-acetamide. Our study first demonstrated a novel potential mechanism for the plant growth promoting endophytes to biosynthesize IAA using plant-derived intermediates. This additional mechanism has deepened our understanding of how bacterial endophytes promote plant health and resilience, offering valuable insights about how plants regulate IAA homeostasis within their internal tissues in association with bacterial endophytes.Graphical

Clinical and In Vitro Safety of Heyndrickxia coagulans AO 1167B: A Double-Blind, Placebo-Controlled Trial.

(1) Background: Heyndrickxia coagulans, a lactic acid-producing bacterium, displays characteristics of both Lactobacillus and Bacillus genera. Clinical evidence suggests its potential health benefits. This study evaluated the safety of H. coagulans AO1167B as a candidate probiotic supplement. (2) Methods: Strain identification was confirmed through morphological, cultural, and genomic analyses, including 16S RNA and whole genome sequencing to assess antimicrobial resistance and virulence factors. Phenotypic tests, such as disk diffusion for antimicrobial resistance, and safety assays for cytotoxicity and hemolytic activity, were conducted. In a phase I, double-blind, placebo-controlled clinical trial, healthy adults were randomized into H. coagulans AO1167B and placebo groups for 60 days. Daily capsule consumption was monitored through clinical and hematological evaluations, adverse event tracking, and health surveys. (3) Results: The genome of H. coagulans AO1167B revealed no concerning features. Disk diffusion tests showed no antimicrobial resistance. The strain exhibited no cytotoxic or hemolytic activity, indicating in vitro safety. No significant differences in clinical or hematological parameters were observed between groups. The most common adverse event, gas, diminished over time. (4) Conclusions: H. coagulans AO1167B demonstrates a suitable safety profile, genetic stability, and probiotic potential for gastrointestinal health, justifying further clinical research.

Bioprospecting of rhizobacteria with antagonistic activity against Fusarium spp., a parasite of cucumber (Cucumis sativus)

Objective: To identify bacteria of genus Bacillus which, isolated from the tomato and cucumber rhizosphere, have an antagonistic effect against Fusarium spp. isolated from cucumber plants in Culiacan, Sinaloa. Design/Methodology/Approach: Both the in vitro and in vivo antagonisms of rhizobacterial isolates against Fusarium spp. on cucumber plants were evaluated. Bacteria with the highest antagonistic effect were identified based on their morphological and molecular characteristics. Results: Isolates FA15 and FA16 showed the highest in vitro biological efficacy against Fusarium spp., with 50.0% and 61.36% inhibition of mycelial growth, respectively. Rhizobacterium FA15 achieved the highest biological efficacy (88.89%) against Fusarium spp. in cucumber plants, while rhizobacterium FA16 recorded a 59.27% efficacy. The morphological and molecular characterization of isolates FA15 and FA16 confirmed a 100% molecular identity between FA15 and Bacillus velezensis and FA16 and B. subtilis. Study Limitations/Implications: The rhizobacteria identified in this study inhibited the mycelial growth of the phytoparasite. Therefore, further studies about these rhizobacteria should be carried out to determine the potential antibiosis that may cause the inhibitory effect. Findings/Conclusions: During the search for native beneficial rhizobacteria, two bacteria that exercise a biologically-effective control over Fusarium spp were identified in Culiacan: Bacillus velezensis and B. subtilis. This finding offers an opportunity in the agricultural biotechnology field to study beneficial native species that could provide an alternative to the use of chemicals.

The genus Bacillus as biological control agent against pests and pathogens for sustainable agriculture

Background/Objective. Bacteria of the Bacillus genus have been studied since their discovery in 1872, for their ability to synthesize metabolites of interest such as proteins used to control phytopathogens. The objective of this research was to analyze the most outstanding species of the Bacillus genus, as well as the main compounds produced by these species, and the perspectives on the use of this bacterial genus for pest and disease control. Materials and Methods. An exhaustive search was carried out in scientific articles and books to gather the most relevant information regarding the Bacillus genus, focusing on its role as a biological control agent for pests and pathogens. Results. The Bacillus genus includes more than 427 taxa, which can be classified into different groups. Among the biological control agents (BCA) are the Bacillus cereus group, which includes B. cereus, B. anthracis, and B. thuringiensis, and the B. subtilis group, which includes B. subtilis, B. licheniformis, and B. pumilus, mainly. B. thuringiensis, through cry genes, has molecular mechanisms to synthesize a crystalline inclusion during sporulation, which contains proteins known as endotoxins or Cry proteins. B. subtilis produces substances with a high potential for biological control, such as volatile organic compounds, as well as bioactive secondary metabolites. Conclusion. The potential of the Bacillus genus to be used as biological control agents is evident. They are widely used for the development of different biopesticides that have advantages over other products. However, it is necessary to continue conducting research from the in vitro area in the laboratory to the field, to help guarantee their biosecurity and effectiveness.