Bacillus Species Research Articles

Promotion of the symbiotic interaction between phagotrophic protists and beneficial bacteria, mediated via a balancing of soil nutrients, reduces the incidence of watermelon Fusarium wilt

Elucidating the microbial mechanisms that trigger Fusarium wilt represents a key step in addressing the barriers to sustainable cropping. However, from the perspective of the complete microbiome, the integrated role of soil nutrients and the microbial community in fields with different rate of wilt disease remains unclear. In this study, we examined the potential interrelationships among rhizosphere soil nutrients, bacteria, fungi, and protists in soils collected from fields in which watermelon had been cultivated for 8 years, and which were characterized by high (HW: 81.25%) or low (LW: 6.25%) incidence of watermelon Fusarium wilt. Soil from HW fields was found to contain a higher density of F. oxysporum (1.30-fold higher than that in the LW soil), along with higher contents of available phosphorus (1.31-fold higher), and available potassium (2.39-fold higher). In addition, the inter-kingdom correlation between protists and bacteria in the HW soil was 2.08-fold higher than that in LW soil. Furthermore, structural equation modeling revealed that an excess of soil available potassium enhances predation by potentially detrimental phagotrophic protists on potentially beneficial bacteria. Collectively, our findings indicate that a balanced nutrient input and the interaction between protists and beneficial bacteria play important roles in controlling the incidence of watermelon Fusarium wilt. These findings have implications for controlling the incidence of watermelon Fusarium wilt based on modifying the nutrient balance of soil and increasing the flora of certain beneficial protists (Cercomonas and Colpoda) that interact symbiotically with species of Bacillus.

Harnessing microbes for self-healing concrete – A review

This review explores the burgeoning field of microbially enhanced construction materials, with a special focus on self-healing concrete, through the lens of microbial biotechnology. Central to this discourse is the innovative use of bacteria, particularly Bacillus species, to address the pervasive issue of microcracks in concrete, a fundamental material in the construction industry. Traditional remedies, such as chemical admixtures and fiber reinforcements, offer partial solutions; however, self-healing concrete represents a paradigm shift, harnessing the natural calcite-precipitating ability of bacteria to autonomously repair cracks, thereby augmenting structural durability and longevity. Delving into the mechanics, the bacteria, embedded within the concrete matrix, remain dormant until crack formation triggers their metabolic pathways, leading to calcite production that effectively seals the fissures. This bio-mediated repair mechanism not only enhances the structural integrity of concrete but also aligns with sustainable construction practices by minimizing maintenance requirements and material wastage. The review extends beyond self-healing phenomena, encompassing broader applications of microbial technology in construction, including bio-concrete, bio-cement, and soil stabilization methods. These applications underscore the versatility of microbes in enhancing material properties such as compressive strength, tensile resilience, and water impermeability. Empirical evidence underscores the necessity of optimizing bacterial dosages and curing conditions to maximize the self-healing efficiency. Future research trajectories should aim to elucidate the complex interactions between microbial agents and concrete matrices, assess long-term performance, and evaluate the environmental and economic sustainability of microbial interventions in construction. The integration of microbial technology in construction materials heralds a new epoch of innovation, offering robust, sustainable, and resilient solutions to enduring challenges in the industry.

Probiotic Bacillus licheniformis ZW3 Alleviates DSS-Induced Colitis and Enhances Gut Homeostasis.

Despite Bacillus species having been extensively utilized in the food industry and biocontrol as part of probiotic preparations, limited knowledge exists regarding their impact on intestinal disorders. In this study, we investigated the effect of Bacillus licheniformis ZW3 (ZW3), a potential probiotic isolated from camel feces, on dextran sulfate sodium (DSS)-induced colitis. The results showed ZW3 partially mitigated body weight loss, disease activity index (DAI), colon shortening, and suppressed immune response in colitis mice, as evidenced by the reduction in the levels of the inflammatory markers IL-1β, TNF-α, and IL-6 (p < 0.05). ZW3 was found to ameliorate DSS-induced dysfunction of the colonic barrier by enhancing mucin 2 (MUC2), zonula occluden-1 (ZO-1), and occludin. Furthermore, enriched beneficial bacteria Lachnospiraceae_NK4A136_group and decreased harmful bacteria Escherichia-Shigella revealed that ZW3 improved the imbalanced gut microbiota. Abnormally elevated uric acid levels in colitis were further normalized upon ZW3 supplementation. Overall, this study emphasized the protective effects of ZW3 in colitis mice as well as some potential applications in the management of inflammation-related diseases.

Overview of insights into the role of Bacillus species in drought stress alleviation and plant disease management

Drought and plant diseases are major constraints on crop production, causing significant losses. As the effects of climate change worsen, there is an urgent need to adopt sustainable agricultural strategies. Plant Growth-Promoting Bacteria (PGPB) are emerging as a promising approach, aimed at enhancing productivity and plant resilience to various stresses. Among them, Bacillus spp. are gaining research interest due to their unique ability to adapt to harsh environmental conditions and produce metabolites of interest in several sectors. Besides improving plant growth and yield, Bacillus plays a pivotal role in enhancing the ability of plants to withstand drought stress mainly by producing of water absorbing substances and enhancing water and nutrient uptake. Some Bacillus species are able to effectively resist plant pathogens through several mechanisms, including antibiosis, competition, induced systemic resistance (ISR), and enriching the microbiome of the soil, enabling them to become important biological agents in the management of plant diseases. This overview aims to highlight the potential of Bacillus species in sustainable agriculture, focusing on their role in mitigating drought stress and controlling plant diseases.

Bacillus subtilis as a host for natural product discovery and engineering of biosynthetic gene clusters.

Covering: up to October 2023Many bioactive natural products are synthesized by microorganisms that are either difficult or impossible to cultivate under laboratory conditions, or that produce only small amounts of the desired compound. By transferring biosynthetic gene clusters (BGCs) into alternative host organisms that are more easily cultured and engineered, larger quantities can be obtained and new analogues with potentially improved biological activity or other desirable properties can be generated. Moreover, expression of cryptic BGCs in a suitable host can facilitate the identification and characterization of novel natural products. Heterologous expression therefore represents a valuable tool for natural product discovery and engineering as it allows the study and manipulation of their biosynthetic pathways in a controlled setting, enabling innovative applications. Bacillus is a genus of Gram-positive bacteria that is widely used in industrial biotechnology as a host for the production of proteins from diverse origins, including enzymes and vaccines. However, despite numerous successful examples, Bacillus species remain underexploited as heterologous hosts for the expression of natural product BGCs. Here, we review important advantages that Bacillus species offer as expression hosts, such as high secretion capacity, natural competence for DNA uptake, and the increasing availability of a wide range of genetic tools for gene expression and strain engineering. We evaluate different strain optimization strategies and other critical factors that have improved the success and efficiency of heterologous natural product biosynthesis in B. subtilis. Finally, future perspectives for using B. subtilis as a heterologous host are discussed, identifying research gaps and promising areas that require further exploration.

ДИНАМИКА КАЧЕСТВЕННОГО И КОЛИЧЕСТВЕННОГО СОСТАВА МИКРОБИОМА ВНУТРЕННИХ ПОВЕРХНОСТЕЙ МЕЖДУНАРОДНОЙ КОСМИЧЕСКОЙ СТАНЦИИ ЗА ПЕРИОД НАБЛЮДЕНИЙ С 2016 ПО 2022 Г.

Residents of the International Space Station (ISS) are various types of bacteria that can act as potential biodegraders of structural materials, which entails disruptions in the operation of various equipment and, indirectly, provoke medical risks and affect the health of crew members with reduced immunity. Since the beginning of ISS exploitation sanitary and microbiological monitoring of the habitat has been carried out for the purpose of timely detection and inactivation of potentially dangerous strains. The study was conducted to investigate the dynamics of the composition and number of bacterial strain species detected on the internal surfaces of the ISS interior and equipment for the period covering from Expedition 46 to Expedition 67 (2016–2022). Samples collected from ISS interior surfaces were grown on nutrient media. Strains were identified by 16S RNA sequencing and MALDI-TOF analysis. The results obtained showed that the number of bacterial community species increases with the increase of the ISS RS operation period. However, this growth was not linear, but was a wave-like repetitive process of changing phases of activation and stagnation of the microbiome. During the period of work of Expeditions 46-67, species of the genera Bacillus and Staphylococcus dominated in the microbiome. Among representatives of the genus Bacillus, the species B. licheniformis dominated. The predominance of bacteria of this genus, apparently, is due to their high resistance to physical and chemical parameters of the ISS habitat, including DNA-damaging factors, such as increased radiation background, which, in turn, can be explained by their ability to spore formation. The results obtained once again indicate the high evolutionary plasticity of B. licheniformis strains, which we discovered earlier in other studies.

PyPGCF: A Python Software for Phylogenomic Analysis, Species Demarcation, Identification of Core, and Fingerprint Proteins of Bacterial Genomes That Are Important for Plants.

This computational protocol describes how to use pyPGCF, a python software package that runs in the linux environment, in order to analyze bacterial genomes and perform: (i) phylogenomic analysis, (ii) species demarcation, (iii) identification of the core proteins of a bacterial genus and its individual species, (iv) identification of species-specific fingerprint proteins that are found in all strains of a species and, at the same time, are absent from all other species of the genus, (v) functional annotation of the core and fingerprint proteins with eggNOG, and (vi) identification of secondary metabolite biosynthetic gene clusters (smBGCs) with antiSMASH. This software has already been implemented to analyze bacterial genera and species that are important for plants (e.g., Pseudomonas, Bacillus, Streptomyces). In addition, we provide a test dataset and example commands showing how to analyze 165 genomes from 55 species of the genus Bacillus. The main advantages of pyPGCF are that: (i) it uses adjustable orthology cut-offs, (ii) it identifies species-specific fingerprints, and (iii) its computational cost scales linearly with the number of genomes being analyzed. Therefore, pyPGCF is able to deal with a very large number of bacterial genomes, in reasonable timescales, using widely available levels of computing power.

Incidence and bacterial load of vegetative Bacillus species in dried milk-based products sold in Upper Egypt

Incidence and bacterial load of vegetative Bacillus species in dried milk-based products sold in Upper Egypt

Microbial landscape of cooked meat products: evaluating quality and safety in vacuum-packaged sausages using culture-dependent and culture-independent methods over 1 year in a sustainable food chain.

Over the last few decades, advancements in process safety and quality methods have been significantly improved, yet new challenges continue to emerge in the sustainable food supply chain. This study aimed to investigate some physicochemical and microbiological parameters impacting meat products, particularly cooked sausages, within a sustainable supply chain, focusing on quality, spoilage populations, and syneresis formation under vacuum conditions. A comprehensive analysis was conducted on 355 samples collected over four seasons using high-throughput sequencing (16S/ITS) and microbiological and physicochemical [pH and water activity (aw)] assessments. The microbial growth predictor MicroLab_ShelfLife was employed, and multiple factor analysis (MFA) and agglomerative hierarchical clustering (AHC) were utilized to understand how these variables influence the microbiome resilience of these products. Lactic and acetic acids were correlated with the microbiome of the sausages and the liquid coating covering them using metagenomic analyses. The study highlighted that 52% of the evaluated meat industries in southeastern Brazil are implementing effective protocols for sustainable chain production. The results indicated that the durability of vacuum-packaged cooked sausages was primarily influenced by storage temperature (RV coefficient of 0.906), initial microbial load (0.755), and aw (0.624). Average microbial counts were 4.30 log cfu/g (initial), 4.61 (7°C/4 days), 4.90 (7°C/8 days), 6.06 (36°C/4 days), and 6.79 (36°C/8 days). Seasonal durability analysis revealed that winter had the highest average durability of 45.58 days, while summer had the lowest at 26.33 days. Yeast populations, including Trichosporon sp. and Candida sp., were identified as key genera influencing spoilage dynamics. In addition, Bacillus species emerged as dominant spoilage microorganisms, highlighting the need for new critical controls. This study demonstrates the impact of metagenomic approaches, including ITS and 16S amplicon sequencing, in revealing microbial community dynamics, storage temperature, and aw, which are essential for developing targeted interventions to enhance food safety and quality sustainably.

Bacillus species for sustainable management of heavy metals in soil: Current research and future challenges

Bacillus species for sustainable management of heavy metals in soil: Current research and future challenges

Lipoproteins are key immunostimulatory components of Bacillus species for dendritic cell maturation and activation

Dendritic cells (DCs) play an important role in immunity by sensing and responding to invasive microbes. Bacillus species are rod-shaped sporulating bacteria that include the pathogenic Bacillus cereus and commensal Bacillus subtilis. Although the interaction between DC and these two Bacillus species has been studied, their key structural component that prompts DC activation is poorly understood. Here, we investigated the two Bacillus species in DC activation by whole cells and their representative microbe-associated molecular patterns (MAMPs). MAMPs including lipoteichoic acid (LTA), lipoprotein (LPP), and peptidoglycan (PGN) were purified from the two Bacillus species. Among the MAMPs, LPP from both species most potently induced the maturation and activation of DCs while PGN, but not LTA, moderately stimulated DCs. LPPs from both Bacillus species enhanced the expression of DC maturation markers including CCR7, CD40, CD80, CD83, CD86, CD205, MHC-I, and MHC-II. Among the MAMPs from B. cereus, PGN most considerably lowered the endocytic capacity of DCs implying DC maturation whereas PGN from B. subtilis lowered it to a similar degree to its LPP. Furthermore, DCs sensitized with LPPs from both Bacillus species and PGN from B. subtilis moderately induced TNF-α and IL-6 production. Notably, a combination of MAMPs did not show any synergistic effect on DC activation. Taken together, our results demonstrate that LPP is the key structural component in B. cereus and B. subtilis that leads to DC activation.

Bacillus Species with Dye-remediation Potential – A Mini Review

Dyes are either natural or synthetic pigments used as colour for different items including textile materials, leather, cosmetics, plastic, paper, printing ink, food, human hair or paintings. The persisting colour and toxic compounds contained in most dyes leads to serious environmental pollution which is unsuitable for the survival of many ecologically important organisms. A wide range of bacterial species have been reported to effectively remediate dyes of various types and classes. This paper reviews bacterial species from the genus Bacillus with the potentiality to remediate synthetic dyes based on published literatures. Bacillus species remediate dyes basically through biosorption and enzymatic active. The most commonly used Bacillus species are Bacillus subtilis, B. cereus, B. megaterium, B. fusiformis, B. odysseyi, B. mycoides, B. paramycoides, B. pseudomycoides, B. flexus, B. cohnii, B. licheniformis, B. spizizenii, B. algicola, B. vallismortis, B. vietnamensis, B. stratosphericus, B. halodurans, B. albus, B. aryabhattai and B. velezensis. Other researches have also proven that mixed cultures of Bacillus species and species from other microbial genera display significant efficiency in the remediation of various dyes. These species produce enzymes and compounds that aid in the breakdown of dyes, thus, reducing their impact to the environment. The use of the aforementioned Bacillus species in the remediation of other dye related environmental pollutants is highly recommended.

Optimisation of Polyhydroxy Butyrate Production by Lysinibacillus fusiformis and Metabacillus indicus isolated from Spent Engine-oil Contaminated Soil

This study isolated bacteria from spent engine oil-contaminated soil and optimized their production of polyhydroxybutyrate (PHB), a biodegradable polymer belonging to the polyesters classes that are of interest as bioderived and biodegradable plastics. Out of 12 bacterial isolates (species of Bacillus, Pseudomonas, Staphylococcus and Lactobacillus) recovered from the spent engine oil contaminated soils, and screened for their capacity to accumulate polyhydroxybutyrate (PHB), only two bacterial isolates (Lysinibacillus fusiformis and Metabacillus indicus), showed significant PHB production. L. fusiformis produced PHB at a concentration of 1.5 g/L, while M. indicus produced PHB at a concentration of 1.0 g/L. Optimal production conditions included a temperature of 35°C, agitation speed of 100 rpm, neutral pH of 7.0, glucose as the carbon source, and peptone as the nitrogen source. Gas chromatography-mass spectrometry confirmed the presence of PHB in the extracted samples, with hexadecanoic acid methyl ester identified as the predominant peak. These findings highlight the potential of bacteria from engine oil-contaminated soil as efficient PHB producers and contribute to the development of sustainable and biodegradable plastics.

Bacterial Assessment of Selected Ready-To-Eat Foods Sold at Some Restaurants Within Federal Polytechnic Offa, Kwara State

Foodborne illness can occur following the intake of food containing high number of viable bacteria and their toxins, although highly common and of public health concern, it is a very preventable occurrence. The research aimed at isolating and identifying the microorganisms that are present in ready to eat foods sold at the Federal Polytechnic, Offa, Kwara State, Nigeria and to study their antibiotics sensitivity patterns. A total of three (3) samples of ready to eat food (White Rice, Beans and Moin moin) were collected from three different canteens within the school premises. Standard methods were used for the total aerobic bacterial counts, coliform counts, Staphylococcus count and Salmonella-Shigella counts. Identification of isolates were performed using various biochemical tests and the antimicrobial sensitivity of bacterial isolates obtained from the food samples was also performed using disc diffusion assay. Beans sample has the highest total aerobic bacteria, Staphylococcus, Salmonella and Shigella counts of 26.67 ± 8.32 x 105 cfu/mL, 3.00 ± 1.00 x 105 cfu/mL and 4.67 ± 3.06 x 105 cfu/mL respectively and Moin moin sample has the highest total coliform count of 6.67 ± 4.93 x 105 cfu/mL. The bacteria isolated from the samples were identified as Enterococcus aerogenes, Proteus vulgaris, Citrobacter freundii, Escherichia coli, Bacillus species, Staphylococcus aureus, Micrococcus luteus and Salmonella enterica. Proteus vulgaris produced the highest zone of inhibition of 15.00 mm with ciprofloxacin while none of the isolates produced a zone of inhibition with rifampicin. It can be concluded from this study that some of the foods sold have considerable number of bacteria which can pose a health risk to the consumers.

Oxidation of Ammonia in Fish Ponds to Nitrates Using Free and Immobilized Nitrifying Bacteria

In fish farming, ammonia stands out as detrimental toxicant, with the potential to significantly impede growth and even lead to fish mortality. The adverse effects of ammonia exposure in aquatic environments primarily stem from elevated concentrations of unionized ammonium (NH3), which can readily permeate gill membranes. This study aimed at assessing the capability of free and mobilized forms of nitrifying bacteria in converting ammonia to nitrates. Nitrifying bacteria were isolated from water samples, resulting in the identification of two Pseudomonas species and two Bacillus species. The Bacillus sp., designated with the isolate code, B4 which exhibited the ability to convert ammonia to both nitrite and nitrate while demonstrating resilience to high ammonia concentrations. When Pseudomonas sp. (C4) and Bacillus sp. (B4) were utilized, the total ammonia concentration was reduced from 2 mg/L to 1.4 mg/L and 1.3 mg/L, respectively. Moreover, the immobilized forms of Pseudomonas sp. C4 and Bacillus sp. B4 achieved a more substantial reduction (75%), lowering the total ammonia concentration from 2 mg/L to 0.5 mg/L within 5-days period. Both nitrifying bacteria not only exhibited ammonia removal capabilities but also demonstrated their proficiency in transforming ammonia into nitrate. Immobilization proved effective in enhancing microbial tolerance to high ammonia concentrations, ultimately leading to improved water quality and the preservation of aquatic animal health.

Bacillus thuringiensis VP4: A potential keratinase producer isolated from poultry waste soils of Himachal Pradesh

Keratinase enzymes are protein hydrolyzing enzymes belonging to the serine hydrolase group and act specifically on keratin proteins to degrade them. The current study was conducted to isolate best keratinase producer bacterial strains. Four Bacillus species (B. cereus PP1- OP748781, B. cereus JP1- OP748782, B. cereus TP1- OP748783 and B. thuringiensis VP4- OP420549), were isolated from the poultry farms of Himachal Pradesh. These strains were evaluated for keratinase production by using chicken feathers in shake flask culture. Among four isolates, Bacillus thuringiensis VP4 showed highest enzymatic activity 343 U/ml. The molecular weight of the keratinase was observed 45 KDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The optimization of enzyme production was done with isolate Bacillus thuringiensis VP4 at various parameters such as temperature, pH and effect of metal ions. The maximum keratinase production was observed at 35°C temperature and pH 10.0. The isolated strain Bacillus thuringiensis VP4 might be used to produce poultry compost through degradation of chicken feathers and poultry waste in short time which may also be helpful for farmers and overcoming environmental pollution.

Production and Applications of Keratinases in Industry

Keratin is an insoluble protein with fibrous structure. It is mainly found in hair,feathers,nail,wool and horn of various animals. These animal accessories can be utilized as animals feed, amino-acids and fertilizers. This insoluble protein is very difficult to degrade and has extreme stability because it has disulfide bonds, hydrogen and hydrophobic interaction present in it. But keratin can be easily digested by keratinase enzyme. Keratinase is an extracellular enzyme. It also degrades keratin in prokaryotic organisms. Microorganisms that produce keratinase are species of Bacillus, Actinobacteria and fungi. It can also be obtained from Streptomyces, Aspergillus, Fervidobacterium, Xanthomonas, Chryseobacteriumand Vibrio. Keratinases produced by microbes arevery diverse due to their chemical as well as physical properties. It is a vigorous enzyme that can survive broad pH and temperature. Their optimum pH range is neutral to alkaline and their optimum temperature reported is 40°C to 60°C. And thermophiles have also been reported for stable microbial activity. Microbial keratinases are cheaply available as compared to conventional producers for keratinases production. They have gained great significance in biotechnology by acting on strong, inflexible cross linked polypeptide structure of keratin instead of ordinary proteolytic enzyme papain, trypsin or pepsin. They are mostly extracted by degrading keratin as substrate. Keratin substrates include feather, hair, wool,horn and nails. This degradation process is helpful in converting keratinous wastes in to fertilizer and poultry feed. Other renowned biotechnological implementations include removing hair from leather by using keratinase, development of bio-polymer from keratinous fiber, delivering drug, hydrolysis of prion proteins and detergent industry. They are also used in converting biomass in to biofuel that significantly boosts power preservation and recycling. The main problem for producing enzymes on large scale is their costly production procedures. This hurdle is overcome by utilizing keratin waste eg feathers of chicken as fermentation substrate on industrial scale. The benefit of utilizing this left over is extremely cost effective fermentation process of keratinase and the effluents are environmental friendly. Keratinase enzyme has become popular and provided newly effective and efficient way for managing waste products by using them on industrial scales as substrates which gives rise to environmental friendly industries for nonstop development.

Lipopeptides: Powerful Antifungal Compounds Produced by Bacillus Species: A Review

Phytopathogens affect the crops each year and hurt the economy of the country. Researchers’ main concern is investigating biocontrol agents’ potential as alternative sources to combat diseases. The Bacillus genus produced various plant growth-promoting compounds useful for managing plant diseases. These agents are harmless to the environment and proven effective antagonists against pathogens. The lipopeptides extracted by Bacillus spp. are effective germ killers, and the most notable among them are iturins, surfactin, fengycin, bacillomycin, and plipastatin, which exhibit potent antibacterial action against a wide variety of phytopathogens. Lipopeptides are non-toxic, biodegradable, and friendly to the natural world. Different lipopeptides have been reviewed for their function and mechanism of action in biocontrol in literature. The purpose of this review is to analyze the previous and recent research work and the mechanisms that involved for the management of disease by lipopeptides produced by Bacillus genus

Isolation, Molecular Characterization, Optimization and Purification of Amylase Enzyme from Locally Isolated Bacillus Species in Different Regions of Munshiganj, Bangladesh

Amylase is a kind of enzyme that facilitates the breakdown of carbohydrates in the body. This enzyme has many applications in different industries. Generally, in pharmaceutical sector it is used for the treatment of pancreatic disorder, pancreatic enzyme replacement therapy (PERT) and as a digestive aid. In this study, the bacterial strain was isolated from soil samples collected from potato dumpsites in different areas of Munshiganj, Bangladesh. After subculturing on the nutrient agar plate, 31 colonies were obtained, of which 9 isolates were found as amylase producer on starch agar medium. Of these, 2 isolates (MC-04 and MC-15) were selected based on the starch hydrolysis clear zone ratio. The isolate MC-04 showed crude enzyme activity of 2.82 IU/ml and specific enzyme activity of 3.42 IU/mg, and isolate MC-15 showed crude enzyme activity of 3.16 IU/ml and specific enzyme activity of 3.77 IU/mg. The best isolate, MC-15, was then identified by morphology, biochemical and molecular characterization and confirmed by 16S-rRNA gene sequencing. After 16S-rRNA sequencing, the isolate (MC-15) was identified as Bacillus subtilis. This amylase production of this strain had also been optimized under certain conditions such as different incubation periods, pH, temperatures and different carbon sources. We found that the best incubation period was 48 h, the optimum pH-7.0, the optimum temperature at 40°C and 2% starch was considered as the best source of carbon. Finally, the crude amylase enzyme was purified by precipitation with ammonium sulfate, dialysis, and single-step gel filtration chromatography. The enzymatic activity of the purified amylase was found to be 8.91 IU/ml, that was 2.82-fold greater enzymatic activity than the raw enzyme. The experiments confirmed that Bacillus subtilis may be a good source of amylase enzyme for industrial application in Bangladesh. Dhaka Univ. J. Pharm. Sci. 22(2): 147-154, 2023 (December)

Determination of Bioremediation Potentials and Plant Growth-Promoting Properties of Bacillus Species Isolated from The Rhizosphere of Dactylorhiza urvilleana

Industrial activities have been one of the biggest factors of environmental destruction by affecting natural resources for decades. Heavy metals, which are one of the greatest dangers especially for the biosphere, can be found in industrial waste. Heavy metals that enter agricultural areas through industrial wastewater cause heavy metals to accumulate in the soil after a certain period. These accumulated heavy metals become an important environmental problem, threatening the life of living beings due to their toxic properties. In soils contaminated with wastewater containing heavy metals, microorganism populations are severely damaged in terms of both number and diversity. This heavy metal accumulation in water and soil has become a global health threat. Alternative processes are needed in the fight against heavy metal pollution. Bioremediation activity, defined as the removal process of environmental pollutants through microorganisms and plants, has gained significant importance in recent years. In our study, the tolerance potentials of Bacillus species isolated from the rhizosphere of Dactylorhiza urvilleana (Steudel) Bauman in the Ovit plateau of Rize province to metals (such as copper, lead, zinc, iron and silver) were investigated. In addition, plant growth promoting Indole Acetic Acid (IAA) production, phosphate dissolution, and ACC (1-Aminocyclopropane-1-Carboxylic acid) deaminase production were determined. It was determined that the isolated Bacillus species had a wide pH growth range and some Bacillus species were salt tolerant. The results showed that Bacillus species have bioremediation potential and plant growth promoting properties. It is thought that the bacteria isolated from the study can be used to make areas with heavy metal pollution suitable for plant cultivation and act as plant growth promoters in these areas. These bacteria strains are planned to be used as cheaper and more effective methods in studies in agriculture or areas with heavy metal pollution.