Bio-mediated detoxification of heavy metal contaminated soil and phytotoxicity reduction using novel strain of Brevundimonas vancanneytii SMA3.

Heavy metals pose a serious environmental threat on a global scale due to their toxicity towards livings. Therefore, removing harmful metals from the environment has become more challenging in recent years. The objective of this study is to isolate, examine, and characterize naturally existing bacteria that possess the ability to mitigate and detoxify heavy metals such as cadmium, mercury, and lead. The selected bacteria SMA3 actively demonstrated metal tolerance during screening and was then employed for biosorption study using a lab-scale technique. The bacterium belonged to Brevundimonas sp., according to 16 S rRNA analysis. To enhance the removal efficiency of SMA3, response surface methodology (RSM) was employed, resulting in the identification of optimized conditions (pH 7, temperature 30 °C and shaking speed 120 rpm) for achieving maximum removal percentage (69.5 % of Cd, 58.6 % of Hg, and 85.1 % of Pb) within 72 h. The structural changes induced by microbial treatment were demonstrated by comparing the findings of FESEM images and FTIR spectra confirming the disappearance of C ^ C, C]O peaks along with C]O, C-O-C, C-H, and O-H bond destabilization following bioaccumulation. Moreover, in terms of phytotoxicity evaluation, it was observed that the treated soil, containing both heavy metals and the selected potent bacterial strain, exhibited reduced toxicity, resulting in improved germination and growth parameters for the seeds of Solanum lycopersicum (tomato plant). Overall, the selected bacterial strain demonstrated its potential for effectively removing multiple metals from the metal contaminated environment.

Elicitation of E-waste (acrylonitrile-butadiene styrene) enriched soil bioremediation and detoxification using Priestia aryabhattai MGP1.

Given the rise in both usage and disposal of dangerous electronics, there is a catastrophic rise in assemblage of electronic waste (e-waste). E-waste including various plastic resins are among the most frequently discarded materials in electronic gadgets. In current digital era, managing e-waste has become universal concern. From the viewpoint of persisting lacuna of e-waste managing methods, the current study is designed to fabricate an eco-friendly e-waste treatment with native soil bacteria employing an enrichment culture method. In the presence of e-waste, indigenous soil microbes were stimulated to degrade e-waste. Microbial cultures were isolated using enrichment medium containing acrylonitrile-butadiene styrene (ABS) as the primary carbon source. Priestia aryabhattai MGP1 was found to be the most dominant e-polymer degrading bacterial isolate, as it was reported to degrade ABS plastic in disposed-off television casings. Furthermore, to increase degradation potential of MGP1, Response Surface Methodology (RSM) was adopted which resulted in optimized conditions (pH 7, shaking-speed 120 rpm, and temperature 30 °C), for maximum degradation (18.88%) after 2 months. The structural changes induced by microbial treatment were demonstrated by comparing the findings of Field emission scanning electron microscopy (FESEM) images and Fourier Transform Infrared (FTIR) spectra confirming the disappearance of ≡ C─H peaks along with C-H, C=C and C ≡N bond destabilization following degradation. Energy-dispersive X-ray (EDX) analyzers of the native and decomposed e-polymer samples revealed a considerable loss in elemental weight % of oxygen by 8.4% and silica by 0.5%. Magnesium, aluminium and chlorine which were previously present in the untreated sample, were also removed after treatment by the bacterial action. When seeds of Vigna radiata were screened using treated soil in the presence of both e-waste and the chosen potent bacterial strain, it was also discovered that there was reduced toxicity in terms of improved germination and growth metrics as a phytotoxicity criterion.

A review on biosurfactant producing bacteria for remediation of petroleum contaminated soils.

The discharge of potentially toxic petroleum hydrocarbons into the environment has been a matter of concern, as these organic pollutants accumulate in many ecosystems due to their hydrophobicity and low bioavailability. Petroleum hydrocarbons are neurotoxic and carcinogenic organic pollutants, extremely harmful to human and environmental health. Traditional treatment methods for removing hydrocarbons from polluted areas, including various mechanical and chemical strategies, are ineffective and costly. However, many indigenous microorganisms in soil and water can utilise hydrocarbon compounds as sources of carbon and energy and hence, can be employed to degrade hydrocarbon contaminants. Therefore, bioremediation using bacteria that degrade petroleum hydrocarbons is commonly viewed as an environmentally acceptable and effective method. The efficacy of bioremediation can be boosted further by using potential biosurfactant-producing microorganisms, as biosurfactants reduce surface tension, promote emulsification and micelle formation, making hydrocarbons bio-available for microbial breakdown. Further, introducing nanoparticles can improve the solubility of hydrophobic hydrocarbons as well as microbial synthesis of biosurfactants, hence establishing a favourable environment for microbial breakdown of these chemicals. The review provides insights into the role of microbes in the bioremediation of soils contaminated with petroleum hydrocarbons and emphasises the significance of biosurfactants and potential biosurfactant-producing bacteria. The review partly focusses on how nanotechnology is being employed in different critical bioremediation processes.

An insight on microbial degradation of benzo[a]pyrene: current status and advances in research.

Benzo[a]pyrene (BaP) is a high molecular weight polycyclic aromatic hydrocarbon produced as a result of incomplete combustion of organic substances. Over the years, the release of BaP in the atmosphere has increased rapidly, risking human lives. BaP can form bonds with DNA leading to the formation of DNA adducts thereby causing cancer. Therefore addressing the problem of its removal from the environment is quite pertinent though it calls for a very cumbersome and tedious process owing to its recalcitrant nature. To resolve such issues many efforts have been made to develop physical and chemical technologies of BaP degradation which have neither been cost-effective nor eco-friendly. Microbial degradation of BaP, on the other hand, has gained much attention due to added advantage of the high level of microbial diversity enabling great potential to degrade the substance without impairing environmental sustainability. Microorganisms produce enzymes like oxygenases, hydrolases and cytochrome P450 that enable BaP degradation. However, microbial degradation of BaP is restricted due to several factors related to its bio-availability and soil properties. Technologies like bio-augmentation and bio-stimulation have served to enhance the degradation rate of BaP. Besides, advanced technologies such as omics and nano-technology have opened new doors for a better future of microbial degradation of BaP and related compounds.

Surveillance of RNase P, PMMoV, and CrAssphage in wastewater as indicators of human fecal concentration across urban sewer neighborhoods, Kentucky.

Wastewater surveillance has been widely used as a supplemental method to track the community infection levels of severe acute respiratory syndrome coronavirus 2. A gap exists in standardized reporting for fecal indicator concentrations, which can be used to calibrate the primary outcome concentrations from wastewater monitoring for use in epidemiological models. To address this, measurements of fecal indicator concentration among wastewater samples collected from sewers and treatment centers in four counties of Kentucky (N = 650) were examined. Results from the untransformed wastewater data over 4 months of sampling indicated that the fecal indicator concentration of human ribonuclease P (RNase P) ranged from 5.1 × 101 to 1.15 × 106 copies/ml, pepper mild mottle virus (PMMoV) ranged from 7.23 × 103 to 3.53 × 107 copies/ml, and cross-assembly phage (CrAssphage) ranged from 9.69 × 103 to 1.85 × 108 copies/ml. The results showed both regional and temporal variability. If fecal indicators are used as normalization factors, knowing the daily sewer system flow of the sample location may matter more than rainfall. RNase P, while it may be suitable as an internal amplification and sample adequacy control, has less utility than PMMoV and CrAssphage as a fecal indicator in wastewater samples when working at different sizes of catchment area. The choice of fecal indicator will impact the results of surveillance studies using this indicator to represent fecal load. Our results contribute broadly to an applicable standard normalization factor and assist in interpreting wastewater data in epidemiological modeling and monitoring.

Colistin Resistance among Human Clinical Isolates from a Tertiary Care Hospital in Nepal.

Background Colistin is increasingly being used for treatment of multidrug resistant (MDR) bacterial infections in human. The plasmid mediated mcr-1 gene was detected recently among the poultry in Nepal. Plasmid mediated colistin resistance among human isolates would severely compromise the treatment of MDR bacterial infections. Objective To find out the prevalence of colistin resistance among the gram-negative bacteria isolated from clinical specimen. Method A descriptive cross-sectional study was conducted in a tertiary care hospital in Kathmandu. Colistin resistance among all the gram negative bacilli (GNB), isolated in a year, from all clinical specimen subjected for aerobic bacterial isolation, was detected by disc diffusion and agar dilution methods. Those with a minimum inhibitory concentration (MIC) > 2 mcg/ml were subjected to polymerase chain reaction for detection of mcr-1 gene. Result A total of 1993 aerobic GNB were isolated from clinical samples received from February 2018 to January 2019. By the agar dilution screening method, 2.1% of the GNBs isolated had MIC of colistin > 2 mcg/ml. None of these possessed the mcr-1 gene. Conclusion Given the occurrence of increased MIC of colistin in the clinical isolates in our set up, nationwide active surveillance would generate data for Nepal. The study for the presence of other genes (chromosomal or plasmid mediated) responsible for the increased MIC of colistin would further guide the control measures.

Optimization studies on biodegradation of atrazine by Bacillus badius ABP6 strain using response surface methodology.

In this study, the optimization of distinctive environmental factors such as pH, temperature, agitation-speed and atrazine-concentration on atrazine degradation by utilizing Bacillus badius ABP6 strain, has been done through response-surface-methodology (RSM). The optimum-conditions after analysis for the maximum atrazine degradation were: pH 7.05, temperature 30.4 °C, agitation-speed 145.7 rpm, and atrazine-concentration 200.9 ppm. The prescribed model was approved for high F-value (95.92), very low P-value (<0.01) and non- significant lack of fit (0.1627). It was observed that under the optimized-conditions, the R2 value of regression models for all the response variables was 0.9897 and the maximum atrazine degradation i.e. 89.7 % was found. Finally for graphical representation, the validated optimum-conditions of variables and responses were simulated using three dimensional plots (3D). The confirmation of the model is successful to suggest the optimization parameters of atrazine degradation under in-situ condition by bacterial isolate employing response-surface-methodology optimization tool of Design expert software (new version 10.0.1).

Augmentation of Atrazine biodegradation by two Bacilli immobilized on α-Fe2O3 magnetic nanoparticles.

In this study, a novel immobilizing carrier with α-Fe2O3 magnetic nanoparticles was developed and used for immobilization of atrazine-degrading bacterial isolates of Bacillus spp. Since the free cells of microorganisms generally not succeed to degrade pollutants; thus, extra treatments are alluring to make strides biodegradation. Scanning electron microscope (SEM) images appeared that after immobilization the bacterial cells were totally retained and entirely distributed on the surface of α-Fe2O3 magnetic nanoparticles. The performance of α-Fe2O3 immobilized cells in atrazine (ATZ) degradation was compared with the free cells, which was about 90.56% in 20 days. Experimental results exhibited that ATZ could be degraded at a broad range of physicochemical parameters viz. pH (4.0 to 9.0), temperature (20 to 45 °C), ATZ concentration (50 to 300 mg L-1) and agitation speed (50 to 300 rpm), which underlines that α-Fe2O3 immobilized cells could tolerate a higher range of ATZ concentration as compared to free cells. This research demonstrated that α-Fe2O3 could be applied as a potential carrier in cell immobilization and biodegradation of ATZ herbicide with greater efficiency.

Epileptic seizure anticipation and localisation of epileptogenic region using EEG signals.

Electric activity of brain gets disturbed prior to epileptic seizure onset. Early prediction of an upcoming seizure can help to increase effectiveness of antiepileptic drugs. The scalp electroencephalogram signals contain information about the dynamics of brain and have been used to predict an upcoming seizure and localise its zone. The objective of this paper is to localise the epileptogenic region and predict an upcoming seizure at the earliest. To localise epileptogenic region, Electroencephalogram signals are categorised into four regions of brain (Frontal, Temporal, Parietal and Central). For each signal seventy-two (72) parameters in frequency domain have been extracted by using ten minute non overlapping window. Four prominent ratio parameters, γ1/γ5, γ3/γ1, θ/γ2 and γ4/θ have been identified as best parameters based on relative fisher score. Zone 2 shows the highest change in all the parameters as compared to the other zones. So, temporal region is identified as the epileptogenic region in this work. For prediction of the epileptic seizure machine learning algorithm artificial neural network (ANN) is proposed. The proposed machine learning algorithm has an accuracy of 92.3%, sensitivity of 100% and specificity of 83.3%.

Bioremediation of chlorpyrifos contaminated soil by two phase bioslurry reactor: Processes evaluation and optimization by Taguchi's design of experimental (DOE) methodology.

Two phase bioreactor was constructed, designed and developed to evaluate the chlorpyrifos remediation. Six biotic and abiotic factors (substrate-loading rate, slurry phase pH, slurry phase dissolved oxygen (DO), soil water ratio, temperature and soil micro flora load) were evaluated by design of experimental (DOE) methodology employing Taguchi's orthogonal array (OA). The selected six factors were considered at two levels L-8 array (2^7, 15 experiments) in the experimental design. The optimum operating conditions obtained from the methodology showed enhanced chlorpyrifos degradation from 283.86µg/g to 955.364µg/g by overall 70.34% of enhancement. In the present study, with the help of few well defined experimental parameters a mathematical model was constructed to understand the complex bioremediation process and optimize the approximate parameters upto great accuracy.

Biodegradation of pulp and paper mill effluent by co-culturing ascomycetous fungi in repeated batch process.

The competence of novel fungal consortium, consisting of Nigrospora sp. LDF00204 (accession no. KP732542) and Curvularia lunata LDF21 (accession no. KU664593), was investigated for the treatment of pulp and paper mill effluent. Fungal consortium exhibited enhanced biomass production under optimized medium conditions, i.e., glucose as carbon (C), sodium nitrate as nitrogen (N), C/N 1.5:0.5, pH 5, temperature 30 °C, and agitation 140 rpm, and significantly reduced biochemical oxygen demand (85.6%), chemical oxygen demand (80%), color (82.3%), and lignin concentration (76.1%) under catalytic enzyme activity; however, unutilized ligninolytic enzymes, such as laccase (Lac), manganese peroxidase (MnP), and lignin peroxidase (LiP), were observed to be 13.5, 11.4, and 9.4 U/ml after the third cycle of effluent treatment in repeated batch process. Scanning electron microscopy (SEM) of fungal consortium revealed their compatibility through intermingled hyphae and spores, while the FTIR spectra confirmed the alteration of functional groups ensuring structural changes during the effluent treatment. Gas chromatography/mass spectroscopy (GC-MS) analysis showed the reduction of complex compounds and development of numerous low-molecular-weight metabolites, such as 1-3-dimethyl benzene, 2-chloro-3-methyl butane, pentadecanoic acid, and 1-2-benzene dicarboxylic acid, during the treatment, demonstrating the massive potential of the novel fungal consortium to degrade recalcitrant industrial pollutants.

Isolation and Characterization of Fipronil Degrading Acinetobacter calcoaceticus and Acinetobacter oleivorans from Rhizospheric Zone of Zea mays.

An enrichment culture technique was used for the isolation of bacteria capable of utilizing fipronil as a sole source of carbon and energy. Based on morphological, biochemical characteristics and phylogenetic analysis of 16S rRNA sequence, the bacterial strains were identified as Acinetobacter calcoaceticus and Acinetobacter oleivorans. Biodegradation experiments were conducted in loamy sand soil samples fortified with fipronil (50 µg kg(-1)) and inoculated with Acinetobacter sp. cells (45 × 10(7) CFU mL(-1)) for 90 days. Soil samples were periodically analyzed by gas liquid chromatography equipped with electron capture detector. Biodegradation of fipronil fitted well with the pseudo first-order kinetics, with rate constant value between 0.041 and 0.051 days(-1). In pot experiments, fipronil and its metabolites fipronil sulfide, fipronil sulfone and fipronil amide were found below quantifiable limit in soil and root, shoot and leaves of Zea mays. These results demonstrated that A. calcoaceticus and A. oleivorans may serve as promising strains in the bioremediation of fipronil-contaminated soils.

Evidence for enhanced collagen type III deposition focally in the territorial matrix of osteoarthritic hip articular cartilage.

OBJECTIVE: To determine if type III collagen is concentrated in the chymotrypsin-extractable collagen pool from osteoarthritic articular cartilage to assess its potential as a biomarker of Osteoarthritis (OA) pathogenic mechanisms. METHODS: Full thickness articular cartilage from grossly normal surfaces was analyzed from femoral heads, obtained at hip replacement surgery, from OA (n = 10) and fracture (n = 10) patients. Collagen, extracted by α-chymotrypsin, was characterized by SDS-PAGE/Western blot analysis, ELISA and immunohistochemistry using monoclonal antibodies specific to collagens types II and III. RESULTS: α-Chymotrypsin extracted more collagen from OA than control cartilage. The extractable pool included collagen types II and III from both OA and control hips. Importantly, OA cartilage contained 6-fold more collagen type III than control cartilage, based on ELISA. The estimated total tissue ratio of collagen III/II was in the 1-10% range for individual OA cartilage samples, based on pepsin-solubilized collagen using SDS-PAGE densitometry. Collagen type III N-propeptide trimers were the main molecular fragments seen on Western blot analysis of OA and control extracts. The chymotrypsin-extracted type II collagen gave primarily full-length α1(II) chains and chain fragments of α1(II) on Western blot analysis from both OA and control tissues. Immunohistochemistry showed that type III collagen was more concentrated in the upper half of OA cartilage and in the territorial matrix around individual chondrocytes and chondrocyte clusters. CONCLUSIONS: The findings confirm that collagen type III deposition occurs in adult articular cartilage but significantly more pronounced in osteoarthritic joints, presenting a potential marker of matrix repair or pathobiology.

Degradation of fipronil by Stenotrophomonas acidaminiphila isolated from rhizospheric soil of Zea mays.

Fipronil is a widely used insecticide in agriculture and can cause potential health hazards to non-target soil invertebrates and nearby aquatic systems. In the present study, a fipronil degrading bacterium was isolated from fipronil contaminated soil, i.e. rhizospheric zone of Zea mays. Morphological, biochemical and molecular characterization of strain indicated that it clearly belongs to Stenotrophomonas acidaminiphila (accession no. KJ396942). A three-factor Box-Behnken experimental design combined with response surface modeling was employed to predict the optimum conditions for fipronil degradation. The optimum pH, temperature and total inocula biomass for the degradation of fipronil were 7.5, 35 °C and 0.175 g L-1, respectively. The bacterial strain was able to metabolize 25 mg L-1 fipronil with 86.14 % degradation in Dorn's broth medium under optimum conditions. Metabolites formed as a result of fipronil degradation were characterized with gas liquid chromatograph. A novel fipronil degradation pathway was proposed for S. acidaminiphila on the basis of metabolites formed. Non-sterilized soil inoculated with S. acidaminiphila was found to follow first order kinetics with a rate constant of 0.046 d-1. Fipronil sulfone, sulfide and amide were formed as the metabolites and were degraded below the quantifiable limit after 90 days of time period. Given the high fipronil degradation observed in the present study, S. acidaminiphila may have potential for use in bioremediation of fipronil contaminated soils.

Biodegradation of isoproturon by Pseudoxanthomonas sp. isolated from herbicide-treated wheat fields of Tarai agro-ecosystem, Pantnagar.

A gram-negative, rod-shaped, isoproturon (IPU) utilizing bacterium was isolated from herbicide-applied wheat fields of Tarai agro-ecosystem, Pantnagar. The phylogenetic sequence analysis based on 16S rRNA sequence revealed that the isolate could be a distinct species within the genus Pseudomonas. The isolate was a close relative of Pseudoxanthomonas japonensis (95 % similarity) and designated as K2. The bacterial isolate showed positive reaction for oxidase, catalase, and 20 carbohydrates using KB009 Part A and B HiCarbohydrate™ Kit. Degradation experiments were conducted using 200 mg l-1 initial IPU as a source of carbon at different pH and temperatures. Maximum IPU degradation by K2 was observed at pH 7.0 and 30 °C, while least degradation at 6.5 pH and 25 °C. Addition of dextrose along with IPU as an auxiliary carbon source increased IPU degradation by 4.72 %, as compared to the IPU degradation without dextrose under optimum conditions. 4-isopropylaniline was detected as a degradation by-product in the medium. The present study demonstrated the IPU metabolizing capacity of a novel bacterial isolate K2 that can be a better choice for the remediation of IPU-contaminated sites.

Evaluating the potential of immobilized bacterial consortium for black liquor biodegradation.

Two indigenous bacterial strains, Bacillus megaterium ETLB-1 (accession no. KC767548) and Pseudomonas plecoglossicida ETLB-3 (accession no. KC767547), isolated from soil contaminated with paper mill effluent, were co-immobilized on corncob cubes to investigate their biodegradation potential against black liquor (BL). Results exhibit conspicuous reduction in color and lignin of BL upto 913.46 Co-Pt and 531.45 mg l(-1), respectively. Reduction in chlorophenols up to 12 mg l(-1) was recorded with highest release of chloride ions, i.e., 1290 mg l(-1). Maximum enzyme activity for lignin peroxidase (LiP), manganese peroxidase (MnP), and laccase (LAC) was recorded as 5.06, 8.13, and 8.23 U ml(-1), respectively, during the treatment. Scanning electron microscopy (SEM) revealed successful immobilization of bacterial strains in porous structures of biomaterial. Gas chromatography/mass spectroscopy (GC/MS) showed formation of certain low molecular weight metabolites such as 4-hydroxy-benzoic acid, 3-hydroxy-4-methoxybenzaldehyde, ferulic acid, and t-cinnamic acid and removal of majority of the compounds (such as teratogenic phthalate derivatives) during the period of treatment. Results demonstrated that the indigenous bacterial consortium possesses excellent decolorization and lignin degradation capability which enables its commercial utilization in effluents treatment system.

Chromium phytoextraction from tannery effluent-contaminated soil by Crotalaria juncea infested with Pseudomonas fluorescens.

The aim of present study was to remediate chromium (Cr)-contaminated soil by Crotalaria juncea in the presence of Pseudomonas fluorescens. Inoculation of P. fluorescens in pot soil grown with C. juncea significantly increased (~2-fold) the water-soluble (Ws) and exchangeable (Ex) Cr contents in contaminated soil under greenhouse condition. It also enhanced the chlorophyll content by 92 % and plant biomass by 99 % as compared to the uninoculated C. juncea plant. The analysis showed that root and shoot uptake of Cr in C. juncea inoculated by P. fluorescens was 3.08- and 2.82-fold, respectively. This research showed that the association of C. juncea and P. fluorescens could be a promising technology for increasing the soil Cr bioavailability and plant growth for successful phytoextraction of Cr from the contaminated soil.

Biosorption kinetics of heavy metals by leaf biomass of Jatropha curcas in single and multi-metal system.

Biosorption of Cu(2+), Zn(2+), and Cr(6+) from aqueous solutions by leaf biomass of Jatropha curcas was investigated as a function of biomass concentration, initial metal ion concentration, contact time, and pH of the solution systematically. The aim of this study was to optimize biosorption process and find out a suitable kinetic model for the metal removal in single and multi-metal system. The experimental data were analyzed using two sorption kinetic models, viz., pseudo-first- and pseudo-second-order equations, to determine the best fit equation for the biosorption of metal ions Cu(2+), Zn(2+), and Cr(6+) onto the leaf biomass of J. curcas in different metal systems. The experimental data fitted well the pseudo-second-order equation and provided the best correlation for the biosorption process. The findings of the present investigation revealed that J. curcas leaf biomass was an eco-friendly and cost-effective biosorbent for the removal of heavy metal ions from wastewater.

Toxic metals biosorption by Jatropha curcas deoiled cake: equilibrium and kinetic studies.

The equilibrium sorption of Cr(VI) and Cu(II) from aqueous solution using Jatropha curcas deoiled cake, has been studied with respect to adsorbent dosage, contact time, pH, and initial metal concentration in batch mode experiments. Removal of Cu(II) by deoiled cake was greater than that of Cr(VI). The adsorbent chemical characteristics, studied by Fourier transform-infrared analysis, suggested that the presence of Cr(VI) and Cu(II) in the biomass influenced the bands corresponding to hydroxyl and carboxyl groups. Desorption studies revealed that maximum metals recovery was achieved by HNO3 followed by CH3COOH and HCl. The Freundlich isotherm model showed good fit to the equilibrium adsorption data. The adsorption kinetics followed the pseudo-second-order model, which provided the best correlation for the biosorption process, and suggested that J. curcas deoiled cake can be used as an efficient biosorbent over other commonly used sorbents for decontamination of Cr(VI)- and Cu(II)-containing wastewater.

Cr(VI) sorption by free and immobilised chromate-reducing bacterial cells in PVA-alginate matrix: equilibrium isotherms and kinetic studies.

Chromate-resistant bacterial strain isolated from the soil of tannery was studied for Cr(VI) bioaccumulation in free and immobilised cells to evaluate its applicability in chromium removal from aqueous solution. Based on the comparative analysis of the 16S rRNA gene, and phenotypic and biochemical characterization, this strain was identified as Paenibacillus xylanilyticus MR12. Mechanism of Cr adsorption was also ascertained by chemical modifications of the bacterial biomass followed by Fourier transform infrared spectroscopy analysis of the cell wall constituents. The equilibrium biosorption analysed using isotherms (Langmuir, Freundlich and Dubinin-Redushkevich) and kinetics models (pseudo-first-order, second-order and Weber-Morris) revealed that the Langmuir model best correlated to experimental data, and Weber-Morris equation well described Cr(VI) biosorption kinetics. Polyvinyl alcohol alginate immobilised cells had the highest Cr(VI) removal efficiency than that of free cells and could also be reused four times for Cr(VI) removal. Complete reduction of chromate in simulated effluent containing Cu(2+), Mg(2+), Mn(2+) and Zn(2+) by immobilised cells, demonstrated potential applications of a novel immobilised bacterial strain MR12, as a vital bioresource in Cr(VI) bioremediation technology.