Bacillus Species Research Articles

Isolation, Screening and Biochemical Characterization of Used Engine Oil Degrading Bacillus Species and Pseudomonas Species

Extensive demand of natural resources has resulted in several large-scale unintentional hydrocarbon oil spills and environmental catastrophes due to the rising demand for fossil fuel energy. These hydrocarbon pollutants have effect on environment and human health. Spectrophotometric and Biochemical Methods are used for the research. Soil sample were collected from two different contaminated areas and used engine oil, the bacteria were isolated and tested for evaluation of bacterial growth and biodegradation by enrichment technique using Bushnell Hass broth with used engine oil as sole carbon source. The results show that Pseudomonas specie were capable of degrading used engine oil which remove 80% of the oil and Bacillus specie which remove 65% of the used engine oil. This illustrates that hydrocarbon biodegrading bacteria can be used for remediation of hydrocarbon contaminated soil.

SCREENING OF INTERNAL AND EXTERNAL BACTERIA FOUND IN FARMED FISH IN RELATION TO FEED QUALITY

Aquaculture in Kenya is progressively developing as an alternative means of human food production and subsistence. An enormous loss in aquaculture has been accelerated by the mortality of Nile Tilapia (Oreochromis niloticus) and African catfish (Clarias gariepinus) fingerlings. This study aimed at screening the internal and external bacteria found in farmed Nile tilapia and African Catfish at Egerton University agro-science fish farm. The microbiology laboratory collected and processed fifteen healthy fish and fish feeds (formulated and commercial). The skin, gills, and intestines were processed and cultured in Salmonella Shigella and Blood agar. Commercial and formulated fish feeds were also processed and cultured in Salmonella Shigella and Blood agar. The resulting bacteria colonies were subjected to morphological examination and biochemical tests for identification. The findings of this study demonstrated the existence of Enterobacteriaceae. Escherichia, Salmonella, and Bacillus species were the most prevalent species identified on the skin, gills, and intestines. Formulated feeds were more contaminated with bacteria than commercial feeds. The presence of the above microorganisms, some of which are pathogens (Salmonella enteritidis, Enterobacter aerogenes, Klebsiella oxytoca) to humans, is an indication that undercooked fish may pose health risks to susceptible human beings and an impediment to the rapid intensification of aquaculture as a result of mortality of fingerings.

Identification of Bacteria Capable of Chromium Bioremediation from the Environment

With the increased urbanization and industrial development, the environment is getting polluted severely day by day. In Bangladesh, the capital city Dhaka is surrounded by a circular river system, most of which are highly polluted due to discharge of municipal and industrial untreated waste water that has been overloaded with different types of toxic heavy metals. Cr (VI) being used in various activities of industries and its improper treatment lead to contamination of the environment. This study aimed to isolate bacteria with chromium bioremediation potential from the environment. A total of 71 bacteria were isolated, of which all grew in the presence of 100 ppm, 93% in 200 ppm, 46% in 400 ppm, 6% in 600 and 4% in 1000 ppm chromium. Fourteen bacteria selected for chromium reduction by Diphenyl Carbazide Assay showed 23-89% reduction. Of these 14 isolates, 5 were tested for biosorption of chromium. Variable sorption of upto 69% was observed. The 16s rDNA of 6 candidate bacteria were sequenced. These isolates were identified as Kurthia gibsonii, Acinetobacter schindleri, Pseudomonas aeruginosa, Exigubacterium sp., Rhodococcus sp., and Bacillus sp. The reduction potential was found to be highest for Bacillus species (78%) and lowest for Kurthia gibsonii (4.8%). This study has successfully identified six potential bacterial candidates for the bioremediation of chromium (VI). Further research into the mechanisms adopted by these bacteria and genetic manipulation will help to formulate a single or mixture of isolates that can efficiently remove hexavalent chromium from polluted water. Plant Tissue Cult. & Biotech. 34(1): 71-81, 2024 (June)

Qualitative Microbiological Assessment of Ready-to-Eat Fruits Sold in Selected Areas of Kaduna Metropolis

Study’s Novelty/Excerpt This study assesses the microbiological quality of ready-to-eat pineapple and watermelon fruits sold in Kaduna Metropolis by systematically assessing bacterial and fungal contamination levels across multiple locations. The research identified a range of bacterial isolates, including Staphylococcus aureus, Bacillus spp., Lactobacillus spp., and Pseudomonas aeruginosa, as well as fungal isolates such as Aspergillus niger, Fusarium solani, Penicillium sp., and Mucor sp. The findings highlight significant variations in contamination levels, emphasizing the need for improved hygienic and safe packaging practices among vendors to mitigate public health risks. Full Abstract This study assessed the microbiological quality of ready-to-eat pineapple and watermelon fruits sold in selected areas of Kaduna Metropolis. A total of 30 samples (15 each) of ready-to-eat pineapple and watermelon fruits were purchased in a randomized manner from three distinct locations, namely Tudun Wada, Ungwan Muazu, and Ungwan Sarki in Kaduna Metropolis. The samples were carefully collected to prevent contaminations and were placed in sterile polythene bags. The preparation and microbiological analysis of all samples were conducted using established microbiological protocols. The pineapple sample obtained from the Tudun Wada region exhibited the highest bacterial mean count, measuring 8.76 x 104, while the watermelon sample from Ungwan Sarki exhibited the lowest bacterial mean count, measuring 5.72 x 104. The bacterial isolates identified in this study included Staphylococcus aureus, various species of Bacillus, Lactobacillus, and Pseudomonas, while the fungal isolates identified included Aspergillus niger, Fusarium solani, Penicillium sp., and Mucor sp. Staphylococcus aureus was the most prevalent bacterium in both samples, accounting for 8 occurrences (26.6%) in pineapple and 7 occurrences (23.3%) in watermelon. Bacillus species were also present, with 4 instances (13.3%) in pineapple and 5 instances (16.6%) in watermelon. Lactobacillus was found in 2 pineapple samples (6.6% of total) and 3 watermelon samples (10% of total). Pseudomonas aeruginosa was minimally detected in only 1 pineapple sample (3.3%). No detection of Pseudomonas aeruginosa was observed in watermelon. These findings suggest that fresh-cut fruits (enclosed in plastic containers or nylon) sold in T/wada, U/muazu, and U/sarki areas of Kaduna metropolis exhibit substandard microbiological quality, posing potential risks to public health. Therefore, it is crucial to improve the hygienic and safe packaging practices employed by these vendors to mitigate possible adverse health consequences.

Molecular identification of biosurfactant-producing bacteria obtained from oil-polluted soil samples in Abakaliki, Ebonyi State, Nigeria

Several human activities have led to environmental pollution with crude oil and other related hydrocarbons. There are various technologies of remediating oil-polluted environments, but the use of biological agents such as biosurfactants are widely practiced, and are generally considered as safe and eco-friendly. This study aimed at isolating and identifying biosurfactant-producing bacteria obtained from oil polluted soil samples in Abakaliki, Ebonyi State, Nigeria using molecular techniques. Six waste oil-contaminated soil samples were collected from mechanic and generator repair workshops, and were analyzed using standard microbiological methods. Nine bacterial isolates were obtained from the waste oil-contaminated soil samples, and were suspected to be Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Molecular identification of the biosurfactant-producing isolates was also carried out using PCR and the genes responsible for biosurfactant production targeted. Oil spreading technique was used to detect the oil displacement activity (ODA) of the isolates. The emulsification index (E24) was calculated and the ability of the extracted biosurfactant to emulsify the hydrocarbons was determined. Pseudomonas aeruginosa had the highest ODA of 28.1 cm while Staphylococcus aureus had the least ODA of 5 cm. Pseudomonas aeruginosa showed E24 of 70.1%, Bacillus subtilis 57.1% while S. aureus showed 32.5%. Hence, Pseudomonas and Bacillus species have good potentials for biosurfactant production, and can be harnessed and utilized in the cleanup of oil polluted soil.

Assessing the probiotic potential and safety of newly isolated Bacillus coagulans VHBAX‐04: in vitro and in silico evaluations

SummaryThe human gastrointestinal tract hosts a diverse and intricate microbial community, a pivotal contributor to human well‐being. An effective strategy for exploring the diversity and potential probiotic attributes of Bacillus species is to isolate them from faecal samples. In this investigation, we scrutinised the in vitro probiotic characteristics of Bacillus coagulans VHBAX‐04, an isolate derived from human faeces. These attributes encompassed acid and gastric juice tolerance, resistance to bile salts and intestinal juice, adhesion capabilities, safety profile, antibiotic resistance pattern, the absence of toxin genes, and antimicrobial efficacy. Furthermore, we conducted in silico analyses to evaluate its probiotic potential. The notable absence of genes associated with mucin degradation, red blood cell lysis, gelatin hydrolysis, or toxin production in B. coagulans VHBAX‐04 certifies its safety as a probiotic. Additionally, the distinct antibiotic resistance pattern of strain VHBAX‐04 suggests its potential for co‐administration with antibiotics. In conclusion, this study underscores the suitability of B. coagulans VHBAX‐04 as a viable probiotic option. Isolation and Evaluation of Bacillus coagulans WBX04: A Probiotic Strain from Human Feces Studied through 16S rRNA Sequencing and In Vitro Tests.

Influence of Bacillus species on mechanical and microstructural properties of concrete

Influence of Bacillus species on mechanical and microstructural properties of concrete

In vitro investigations on interference of selected probiotic candidates with Campylobacter jejuni adhesion and invasion of primary chicken derived cecal and Caco-2 cells

BackgroundCampylobacter (C.) jejuni is one of the most important bacterial foodborne pathogens worldwide. Probiotics such as Lactobacillus or Bacillus species are considered one option for reducing the colonization rate and magnitude in poultry, the most frequent source of human infections. Due to the lack of suitable avian in vitro models such as chicken intestinal cell lines, especially those derived from the cecum, most in vitro studies on C. jejuni host interaction have been conducted with human intestinal cell lines. In this study, we compared C. jejuni-cell interactions between primary chicken cecal cells and the human intestinal cell line Caco-2, which is derived from colorectal adenocarcinoma, and investigated possible interfering effects of selected probiotic candidates.ResultsWe detected differences in adhesion and invasion between the two tested gut cell types and between different C. jejuni strains. The probiotic inhibition of C. jejuni adhesion and invasion of human and avian gut cells was affected by host cell type, investigated C. jejuni strain and time points of probiotic treatment. Additionally, our results suggest a possible correlation between C. jejuni invasion and the detected increase in IL-6 mRNA expression.ConclusionsOur results indicate distinct differences between avian and human gut cells in their interaction with C. jejuni. Therefore, data obtained in one host species on C. jejuni-host interaction may not easily be transferrable to another one. The factors influencing the variable efficacy of probiotic intervention in chicken and human derived cells should be investigated further.

Effect of Process Parameters on Immobilization of Recombinant Escherichia coli on Coconut Fiber

Escherichia coli (E. coli) is the earliest and most widely used host to produce recombinant proteins, one such example being cyclodextrin glucanotransferase (CGTase) which has found application in numerous industries such as food, environmental engineering and pharmaceutical. The recombinant protein in E. coli was applied to overcome the low output of CGTase from Bacillus species such as Bacillus lehensis and Bacillus licheniformis. However, cell lysis and plasmid instability have been some of the stumbling blocks during the production of recombinant protein in E. coli. Therefore, cell immobilization has been proposed as a way to increase CGTase production while maintaining high cell stability. The objective of this study is to immobilize recombinant E. coli on coconut fiber. The effect of the process parameters, namely pH level (5, 6, 7, 8, and 9), contact time (12, 15, 18, 21, 24, and 27 hours), and temperature (20, 25, 30, 35, and 40 °C), towards the immobilization of recombinant E. coli onto coconut fiber was studied. The optimal pH resulted in the highest immobilization yield was pH 8 (58.90%). The best contact time for the highest immobilization yield (57.59%) was 24 hours. The optimum temperature was identified at 25 °C with immobilization yield of 58.78%. Hence, the optimum conditions could improve the immobilization of recombinant E. coli on the carrier and the coconut fibre was an appropriate carrier material for cell immobilization process for the high CGTase production with high cell stability.

Molecular Characterization Reveals Biodiversity and Biopotential of Rhizobacterial Isolates of Bacillus Spp

Bacillus species appearas the most attractive plant growth-promoting rhizobacteria (PGPR) and alternative to synthetic chemical pesticides. The present study examined the antagonistic potential of spore forming-Bacilli isolated from organic farm soil samples of Allahabad, India. Eighty-seven Bacillus strains were isolated and characterized based on their morphological, plant growth promoting traits and molecular characteristics. The diversity analysis used 16S-rDNA, BOX-element, and enterobacterial repetitive intergenic consensus. Two strains, PR30 and PR32, later identified as Bacillus sp., exhibited potent in vitro antagonistic activity against Ralstonia solanaceorum. These isolates produced copious amounts of multiple PGP traits, such as indole-3-acetic acid (40.0 and 54.5 μg/mL), phosphate solubilization index (PSI) (4.4 and 5.3), ammonia, siderophore (3 and 4 cm), and 1-aminocyclopropane-1-carboxylate deaminase (8.1and 9.2 μM/mg//h) and hydrogen cyanide. These isolates were subjected to the antibiotic sensitivity test. The two potent isolates based on the higher antagonistic and the best plant growth-promoting ability were selected for plant growth-promoting response studies in tomatoe, broccoli, and chickpea. In the pot study, Bacillus subtilis (PR30 and PR31) showed significant improvement in seed germination (27–34%), root length (20–50%), shoot length (20–40%), vigor index (50–75%), carotenoid content (0.543–1.733), and lycopene content (2.333–2.646 mg/100 g) in tomato, broccoli, and chickpea. The present study demonstrated the production of multiple plant growth-promoting traits by the isolates and their potential as effective bioinoculants for plant growth promotion and biocontrol of phytopathogens.

Transforming microbial pigment into therapeutic revelation: extraction and characterization of pyocyanin from Pseudomonas aeruginosa and its therapeutic potential as an antibacterial and anticancer agent

BackgroundThe objectives of the current study were to extract pyocyanin from Pseudomonas aeruginosa clinical isolates, characterize its chemical nature, and assess its biological activity against different bacteria and cancer cells. Due to its diverse bioactive properties, pyocyanin, being one of the virulence factors of P. aeruginosa, holds a promising, safe, and available therapeutic potential.Methods30 clinical P. aeruginosa isolates were collected from different sources of infections and identified by routine methods, the VITEK 2 compact system, and 16 S rRNA. The phenazine-modifying genes (phzM, phzS) were identified using polymerase chain reaction (PCR). Pyocyanin chemical characterization included UV-Vis spectrophotometry, Fourier Transform Infra-Red spectroscopy (FTIR), Gas Chromatography-Mass Spectrometry (GC-MS), and Liquid Chromatography-Mass Spectrometry (LC-MS). The biological activity of pyocyanin was explored by determining the MIC values against different clinical bacterial strains and assessing its anticancer activity against A549, MDA-MB-231, and Caco-2 cancer cell lines using cytotoxicity, wound healing and colony forming assays.ResultsAll identified isolates harboured at least one of the phzM or phzS genes. The co-presence of both genes was demonstrated in 13 isolates. The UV-VIS absorbance peaks were maxima at 215, 265, 385, and 520 nm. FTIR could identify the characteristic pyocyanin functional groups, whereas both GC-MS and LC-MS elucidated the chemical formula C11H18N2O2, with a molecular weight 210. The quadri-technical analytical approaches confirmed the chemical nature of the extracted pyocyanin. The extract showed broad-spectrum antibacterial activity, with the greatest activity against Bacillus, Staphylococcus, and Streptococcus species (MICs 31.25–125 µg/mL), followed by E. coli isolates (MICs 250–1000 µg/mL). Regarding the anticancer activity, the pyocyanin extract showed IC50 values against A549, MDA-MB-231, and Caco-2 cancer cell lines of 130, 105, and 187.9 µg/mL, respectively. Furthermore, pyocyanin has markedly suppressed colony formation and migratory abilities in these cells.ConclusionsThe extracted pyocyanin has demonstrated to be a potentially effective candidate against various bacterial infections and cancers. Hence, the current findings could contribute to producing this natural compound easily through an affordable method. Nonetheless, future studies are required to investigate pyocyanin’s effects in vivo and analyse the results of combining it with other traditional antibiotics or anticancer drugs.

Unlocking the growth-promoting and antagonistic power: A comprehensive whole genome study on Bacillus velezensis strains

Bacillus species are extensively documented as plant growth-promoting rhizobacteria, contributing significantly to the enhancement of soil fertility, nutrient recycling, and the control of phytopathogens. Utilizing them as biocontrol agents represents an environmentally friendly strategy, particularly within the rhizospheric community. This study presents the comprehensive genome sequences of three B. velezensis strains (LGMB12, LGMB319, and LGMB426) which were previously isolated from root samples of maize (Zea mays L.), along with a type strain FZB42. The research assesses the capability of the three strains for antagonizing fungi, specifically Fusarium graminearum, Fusarium verticillioides, Colletotrichum graminicola, and Stenocarpella sp. In paired cultures involving maize fungi, treatments containing bacteria B. velezensis exhibited statistically significant differences compared to both negative and positive treatments in terms of antagonism. Furthermore, genome mining techniques were employed to explore their inherent antagonistic potential. The assembly revealed that strains LGMB12, LGMB319, LGMB426, and FZB42 exhibit genome sizes of 4,187,541 bp, 4,244,954 bp, 3,976,537 bp, and 3,990,518 respectively. Their respective G + C content stands at 46.42 %, 46.50 %, 46.51 %, and 46.38 %. Moreover, the genomes present multiple gene clusters responsible for the synthesis of secondary metabolites and carbohydrate-active enzymes (CAZymes). These clusters highlight a diverse array of antibacterial and antifungal properties, complemented by numerous plant growth-promoting genes. These results highlight the potential of B. velezensis LGMB12, LGMB319, and LGMB426 strains as biocontrol and plant growth promotion agents, being promising candidates for further studies in agricultural production, including field trials.

Bio-Efficacy of Bacillus Species in the Management of Root-Knot Nematode Pest of Pepper

Bio-Efficacy of Bacillus Species in the Management of Root-Knot Nematode Pest of Pepper

Deficiency in Opu Systems Imparts Salt-Sensitivity to Weizmannia coagulans.

Weizmannia coagulans can be used as a starter strain in fermented foods or as a probiotic. However, it is salt-sensitive. Here, W. coagulans genomes were compared with the genomes of strains of Bacillus species (B. licheniformis, B. siamensis, B. subtilis, and B. velezensis) that were isolated from fermented foods and show salt tolerance, to identify the basis for the salt-sensitivity of W. coagulans. Osmoprotectant uptake (Opu) systems transport compatible solutes into cells to help them tolerate osmotic stress. B. siamensis, B. subtilis, and B. velezensis each possess five Opu systems (OpuA, OpuB, OpuC, OpuD, and OpuE); B. licheniformis has all except OpuB. However, W. coagulans only has the OpuC system. Based on these findings, the opuA and opuB operons, and the opuD and opuE genes, were amplified from B. velezensis. Expression of each of these systems, respectively, in W. coagulans increased salt-tolerance. W. coagulans expressing B. velezensis opuA, opuD, or opuE grew in 10.5% NaCl (w/v), whereas wild-type W. coagulans could not grow in 3.5% NaCl. The salt resistance of B. subtilis was also increased by overexpression of B. velezensis opuA, opuB, opuD, or opuE. These results indicate that the salt-susceptibility of W. coagulans arises because it is deficient in Opu systems.

Biosorption of copper, nickel, and manganese as well as the production of metal nanoparticles by Bacillus species isolated from soils contaminated with electronic wastes.

Improper electronic waste management in the world especially in developing countries such as Iran has resulted in environmental pollution. Copper, nickel, and manganese are from the most concerned soil contaminating heavy metals which found in many electronic devices that are not properly processed. The aim of this study was to investigate the biological removal of copper, nickel, and manganese by Bacillus species isolated from a landfill of electronic waste (Zainal Pass hills located in Isfahan, Iran) which is the and to produce nanoparticles from the studied metals by the isolated bacteria. The amounts of copper, nickel, and manganese in the soil was measured as 1.9 × 104 mg/kg, 0.011 × 104 mg/kg and 0.013 × 104 mg/kg, respectively based on ICP-OES analysis, which was significantly higher than normal (0.02 mg/kg, 0.05 mg/kg, and 2 mg/kg, respectively. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of metals on the bacterial isolates was determined. The biosorption of metals by the bacteria was evaluated by inductively coupled plasma optical emission spectroscopy (ICP-OES). The metal nanoparticles were synthetized utilizing the isolates in culture media containing the heavy metals with the concentrations to which the isolates had shown resistance. X ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were used for the evaluation of the fabrication of the produced metal nanoparticles. Based on the findings of this study, a total of 15 bacterial isolates were obtained from the soil samples. The obtained MICs of copper, nickel, and manganese on the isolates were 40-300 mM, 4-10 mM, and 60-120 mM, respectively. The most resistant isolates to copper were FM1 and FM2 which were able to bio-remove 79.81% and 68.69% of the metal, respectively. FM4 and FM5 were respectively the most resistant isolate to nickel and manganese and were able to bio-remove 86.74% and 91.96% of the metals, respectively. FM1, FM2, FM4, and FM5 was molecularly identified as Bacillus cereus, Bacillus thuringiensis, Bacillus paramycoides, and Bacillus wiedmannii, respectively. The results of XRD, SEM and EDS showed conversion of the copper and manganese into spherical and oval nanoparticles with the approximate sizes of 20-40 nm. Due to the fact that the novel strains in this study showed high resistance to copper, nickel, and manganese and high adsorption of the metals, they can be used in the future, as suitable strains for the bio-removal of these metals from electronic and other industrial wastes.

Seed treatment with Bacillus bacteria improves maize production: a narrative review

Maize (Zea mays L.) is an important crop in relation to its production and consumption. Production of maize is constrained by soil infertility and poor quality seed. Microbial technologies like seed treatment with Bacillus bacteria improves the productivity of maize on infertile soil. However, due to variations in maize growth environments and Bacillus species, this review was conducted to identify the common species of Bacillus species used for seed treatment, and provide an overview of the effect of seed treatment with Bacillus on maize growth and yield. Results show that Bacillus subtilis, Bacillus pumilus and Bacillus amyloliquefaciens were the dominant species used for seed treatment. Bacillus was used as both a biofertiliser and biopesticide. The conspicuous positive effects of Bacillus were in plant height, shoot and root length, and shoot dry matter depending on the species. In terms of grain yield, Bacillus subtilis (8502 kg ha-1), Bacillus amyloliquefaciens (6822 kg ha-1) and Bacillus safensis (5562 kg ha-1) were the bacterial species that had an overall pronounced effect. The highest increase in grain yield was in the interactive effect of Bacillus megaterium + Bacillus licheniformis (18.1%) and sole Bacillus subtilis (15.6%), while Bacillus pumilus reduced grain yield by 4.8%. This shows that the improvement of maize productivity using Bacillus bacteria requires careful selection of the species for seed treatment.

Microbial detoxification of chlorpyrifos, profenofos, monocrotophos, and dimethoate by a multifaceted rhizospheric Bacillus cereus strain PM38 and its potential for the growth promotion in cotton.

Bacillus genera, especially among rhizobacteria, are known for their ability to promote plant growth and their effectiveness in alleviating several stress conditions. This study aimed to utilize indigenous Bacillus cereus PM38 to degrade four organophosphate pesticides (OPs) such as chlorpyrifos (CP), profenofos (PF), monocrotophos (MCP), and dimethoate (DMT) to mitigate the adverse effects of these pesticides on cotton crop growth. Strain PM38 exhibited distinct characteristics that set it apart from other Bacillus species. These include the production of extracellular enzymes, hydrogen cyanide, exopolysaccharides, Indol-3-acetic acid (166.8μg/mL), siderophores (47.3μg/mL), 1-aminocyclopropane-1-carboxylate deaminase activity (32.4μg/mL), and phosphorus solubilization (162.9μg/mL), all observed at higher concentrations. This strain has also shown tolerance to salinity (1200mM), drought (20% PEG-6000), and copper and cadmium (1200mg/L). The amplification of multi-stress-responsive genes, such as acdS, ituC, czcD, nifH, sfp, and pqqE, further confirmed the plant growth regulation and abiotic stress tolerance capability in strain PM38. Following the high-performance liquid chromatography (HPLC) analysis, the results showed striking compatibility with the first kinetic model. Strain PM38 efficiently degraded CP (98.4%), PF (99.7%), MCP (100%), and DMT (95.5%) at a concentration of 300ppm over 48h at 35°C under optimum pH conditions, showing high coefficients of determination (R2) of 0.974, 0.967, 0.992, and 0.972, respectively. The Fourier transform infrared spectroscopy (FTIR) analysis and the presence of opd, mpd, and opdA genes in the strain PM38 further supported the potential to degrade OPs. In addition, inoculating cotton seedlings with PM38 improved root length under stressful conditions. Inoculation of strain PM38 reduces stress by minimizing proline, thiobarbituric acid-reactive compounds, and electrolyte leakage. The strain PM38 has the potential to be a good multi-stress-tolerant option for a biological pest control agent capable of improving global food security and managing contaminated sites.

Orthotic Thermoplastic Demonstrates a Similar Contamination Potential with Bacillus Bacteria Recovered from Thermoplastic Radiation Therapy Patient Masks

Thermoplastics used to construct a variety of patient medical devices can become contaminated by harmful bacteria. We investigated whether two different Bacillus species recovered from patient radiation therapy thermoplastic masks could similarly contaminate thermoplastic material used to construct patient orthoses (splints). Bacillus bacteria form dormant spores, which have been shown to enhance its attachment to thermoplastics. Bacterial attachment and recovery were examined using an orthotic thermoplastic with an anti-stick coating being compared to uncoated material used in radiation therapy applications. Triplicate sample squares were seeded with a saline suspension of either B. cereus (MAB03F) or B. megaterium (DAB01F) containing a similar number of spores. Squares were subsequently sampled at 1 h, 1 week, 2 weeks, 4 weeks, and 8 weeks. The number of recovered bacteria was counted. Differences in material hydrophobicity were determined by water contact angle analysis. Both Bacillus species attached to each material within 1 h, and their spores were recovered at 8 weeks. However, a decreasing trend in adhesion, over time, was noted to the coated material with an opposite increasing trend in the uncoated material. Decreased Bacillus species spore adhesion to coated material with a lower hydrophobicity suggests a greater potential for spore transfer to patients wearing contaminated orthoses.

Surface-associated residues in subtilisins contribute to poly-L-lactic acid depolymerization via enzyme adsorption.

Poly-L-lactic acid (PLLA) is currently the most abundant bioplastic; however, limited environmental biodegradability and few recycling options diminish its value as a biodegradable commodity. Enzymatic recycling is one strategy for ensuring circularity of PLLA, but this approach requires a thorough understanding of enzymatic mechanisms and protein engineering strategies to enhance activity. In this study, we engineer PLLA depolymerizing subtilisin enzymes originating from Bacillus species to elucidate the molecular mechanisms dictating their PLLA depolymerization activity and to improve their function. The surface-associated amino acids of two closely related subtilisin homologues originating from Bacillus subtilis (BsAprE) and Bacillus pumilus (BpAprE) were compared, as they were previously engineered to have nearly identical active sites, but still varied greatly in PLLA depolymerizing activity. Further analysis identified several surface-associated amino acids in BpAprE that lead to enhanced PLLA depolymerization activity when engineered into BsAprE. In silico protein modelling demonstrated increased enzyme surface hydrophobicity in engineered BsAprE variants and revealed a structural motif favoured for PLLA depolymerization. Experimental evidence suggests that increases in activity are associated with enhanced polymer binding as opposed to substrate specificity. These data highlight enzyme adsorption as a key factor in PLLA depolymerization by subtilisins.

Biodegradation of Malachite Green Dye by Novel Isolated Bacillus Species AAV from Garden Soil

Malachite green (MG) dye commonly use in textile and paper printing industry to a great extent. Textile effluent released from industries including dyes must be treated before release into the environment due to its toxic nature. In present study, newly isolated bacterial species was able to decolorize MG dye (100%) in 1 h at shaking condition and 94% at static condition. 16S rRNA analysis revealed an isolate as Bacillus sp. AAV. Lignin peroxidase, laccase and tyrosinase enzymes from Bacillus sp. AAV showed significant increased activity during decolourisation. There was 138, 369 and 164% trek in activity of LiP, laccase and tyrosinase after MG decolourization, respectively. Bacillus sp. AAV could decolourise MG efficiently at alkaline pH (8-10) and at 40°C temperature. Biodegradation was monitored by UV-VIS spectrophotometer. Gas chromatography-Mass spectroscopy data was used to propose the degradation pathway of MG dye. The newly isolated Bacillus sp. AAV was able to decolourise ten various types of dyes and textile dye effluent. Phytotoxicity test by using seeds of wheat and sorghum was also carried out to check toxicity of MG dye metabolites. The study reveals that there was no toxicity with respect to tested seeds. This study suggests that Bacillus sp. AAV could be a useful microorganism or its enzyme system for textile dyes and effluent treatment.