Biosorption Of Cu Research Articles

Binary Biosorption of Cu(II) and Cr(VI) by Naturally Formed Biofilm Matrices

Water pollution poses a significant ecological threat, contributing to the widespread degradation of aquatic ecosystems. Among the pollutants, heavy metals pose severe risks to both organisms and human health, emphasizing the urgent need for effective pollution control technologies. Biosorption presents a promising, cost-effective, and environmentally friendly solution to mitigate heavy metal contamination. Biofilms, consisting of microbial communities, have emerged as potential biosorbents for heavy metals. Since heavy metals can exist as cations and anions concurrently in aquatic environments, understanding their behavior in binary systems is essential for biosorption strategies. This study focuses on the binary biosorption of Cu(II) and Cr(VI), representing cationic and anionic heavy metals. Specific adsorption sites are identified by analyzing adsorption kinetics, isotherms, and IR spectra of biofilms. The results indicate that biofilms, in a binary scenario, demonstrate nearly identical adsorption capacities for Cu(II) and Cr(VI). Moreover, the adsorption process follows the Langmuir adsorption model, emphasizing the potential of biofilms as effective biosorbents for the simultaneous removal of cationic and anionic heavy metals. This study advocates for a sustainable approach to heavy metal remediation through the utilization of biofilms.

Biosorption of Cu+ 2 by Green Algae, Ulva fasciata: Optimization by Response Surface Methodology

AbstractU. fasciata biomass, a green algae was used as adsorbent, investigated and optimized the environmental parameters using central factorial design for the Cu+ 2 removal. Biosorption of Cu+ 2 involves the functional groups –CO, –OH, and N–H of U. fasciata biomass. Various parameters were estimated using Response Surface Methodology (RSM), including pH (4–6), initial Cu+ 2 concentration (60–140 mg L− 1), biomass dosage (0.08–0.40 g L− 1) and temperature (20–40 °C). It was found that the uptake of Cu+ 2 by U. fasciata was 62.31 mg L− 1 at an initial concentration of 80 mg L− 1, a temperature of 35 °C, and a pH of 5.245. In order to analyze the equilibrium data, applied Langmuir, Freundlich, Langmuir-Friendly (L-R), and Redlich-Peterson (L-R) isotherm models. The multiple mechanisms were involved in the removal of Cu+ 2 including chelation, ion-exchange and adsorption on UF biomass. It is believed that the U. fasciata biomass is a suitable material for the removal of Cu+ 2 ions from wastewaters.

Biosorption of Cu(II) Ions by Water Hyacinth Leaf Powder: Process Performance, Kinetics, and Biosorption Isotherm

The water hyacinth leaf powder (WH) was used to adsorb Cu(II) from wastewater. The WH was modified through sulfuric acid (A-WH) and sodium hydroxide (B-WH) treatments. The biosorption was studied with various initial pH, initial Cu(II) concentrations, and biosorp-tion time. The results show that the biosorption capacities of the biosorbents increase with the initial Cu(II) concentration. The optimum pH for the biosorption was 7.5, 7.0, and 7.5 for the WH, A-WH, and B-WH, respectively. The SEM images of the raw and treated WH revealed that alkali treatment could remove lignin more than the acid treatment, leaving more macropores in the B-WH than in the A-WH. The acid and alkali treatments to the WH leaf increase the biosorption capacity of the WH for Cu (II). The pseudo-second-order kinetic model can represent the dynamic behavior of the biosorption better than the pseudo-first-order model. The Langmuir model is better than the Freundlich model for describing the biosorption isotherm. The maximum biosorption capacities of the biosorbents predicted by the Langmuir model were 14.92 mg g−1, 18.32 mg g−1, and 23.27 mg g−1 for WH, A-WH, and B-WH, respectively.

Comparison of the bioaccumulation and biosorption of copper ions by Rhizopus delemar and Candida lipolytica

In this study, the bioaccumulation of Cu(II) ion by Rhizopus delemar and Candida lipolytica was investigated and the bioaccumulation and biosorption of Cu(II) ions by Candida lipolytica compared. The specific growth rate and the maximum microorganism concentration of both microorganisms increased with increasing initial molasses concentration whereas decreased with increasing initial Cu(II) ion concentrations up to 250 mg/L. Accoding to Monod equation, the maximum specific growth rate and saturation constant for C. lipolytica and R. delemar were determined as 0.335 h−1-32.330 g/L and 0.406 h−1-24.182 g/L, respectively. The bioaccumulation efficiencies of R. delemar and C. lipolytica were determined as 74.18% and 67.30% in the presence of 50 mg/L Cu(II), respectively. At pH 4.0, the maximum biosorption rate (4.72 mg/g min) and the biosorbed Cu(II) ion concentration (49.0 mg/L) were obtained for C. lipolytica and these values increased with increasing Cu(II) concentration. Cu(II) biosorption by C. lipolytica fitted well to the Langmuir isotherm model and pseudo-second-order kinetic model and maximum adsorption capacity was found as 114.942 mg/g. The bioaccumulated Cu(II) was found to be 21.5 mg/g whereas the amounts of biosorbed Cu(II) were calculated as 53 mg/g by C. lipolytica at a concentration of 100 mg/L of Cu(II).

Synthesis, Characterization, and Biosorption of Cu2+ and Pb2+ Ions from an Aqueous Solution Using Biochar Derived from Orange Peels.

In this study, orange peel (OP) biochar was used as a bio-sorbent for the removal of copper and lead from wastewater in single and binary systems. The equilibrium and kinetic studies were conducted at a pH value of 5, which was the maximum adsorption pH value for both metal ions. The equilibrium studies were investigated at a varying initial concentration (10-200 mg/L) with a constant dosage of 0.1 g, while the kinetic studies were conducted at a fixed initial concentration of 200 mg/L with a constant dosage of 1 g/L for both single and binary systems. The maximum adsorption capacity of the orange peel biochar was 28.06 mg/g, 26.83 mg/g, 30.12 mg/g and 27.71 mg/g for single Cu2+, binary Cu2+, single Pb2+ and binary Pb2+ systems, respectively. The Langmuir isotherm model fitted the experimental data, suggesting that adsorption occurred on a monolayer, while the pseudo-second-order model performed well with the kinetic data. The point of zero charge (pHpzc) of the orange peel biochar was found to be 10.03, which revealed that the surface of the bio-sorbent contains basic groups. A Fourier infrared transform (FTIR) spectroscope and scanning electron microscope, coupled with energy dispersive x-ray (SEM-EDX) and x-ray diffraction analyses, were used to determine the functional groups, surface morphology, and inorganic elements present on the surface of the bio-sorbent, respectively. The results obtained have shown that orange peel biochar is efficient for the removal of Cu2+ and Pb2+ ions from an aqueous solution.

Biosorption of Cu (II) and Pb (II) ions using acid modified Senna tora pods with a focus on isotherms and kinetics studies

The removal of heavy metals by biosorption method using agricultural waste and plant materials has become a powerful technology that is been explored for the treatment of domestic and industrial waste water due to its easy operating requirements and low cost. This work reports the application of Senna tora pods for the elimination of heavy metals (Cu and Pb ions) by biosorption in batch system. The effects of pH, contact time, dosage and initial concentration were evaluated. The kinetic and isotherms models for the Cu(II)/Pb(II) biosorption were tested basically by the pseudo-first-order and pseudo-second order kinetic models. Langmuir, Freundlich and Temkin isotherms models have also been used to fit equilibrium adsorption data. The monolayer sorption capacity (qL) of Cu(II) was found to be 0.791 mg/g while that of Pb(II) was 0.51 mg/g.The low Langmuir constant (KL) values suggests that the adsorption process was largely due to physisorption mechanism. The adsorption kinetics follow a pseudo-first-order model for Cu(II) and pseudo-second-order model for Pb(II), and the equilibrium data is suitably fitted by the Langmuir models than the Freundlich due to the high R2 values of 0.989 and 0.97 for Cu(II) and Pb(II) ions respectively. Consequently, there exists a closeness of the calculated sorption capacity (qcal) to the experimental sorption capacity (qex). In conclusion, the study generally showed that Senna tora pods is a potential and efficient adsorbent that could be explore for the bioremediation of heavy metal contaminated industrial wastewater.

Evaluation of Thermodynamic Parameters for Cu(II) Ions Biosorption on Algae Biomass and Derived Biochars

The removal of metal ions by biosorption on inexpensive materials is still a challenge for environmental engineering research. In this study, marine green algae biomass (Ulva lactuca sp.) and the biochars obtained from this biomass, at 320 °C (BC-320) and 550 °C (BC-550), were used as biosorbents for the removal of Cu(II) ions from aqueous solution. In addition to comparing the biosorption capacities, the determination of the thermodynamic parameters allows the choice of the most suitable material for the biosorption processes. The experimental results, obtained for Cu(II) ions biosorption on each biosorbent (algae biomass (AB), BC-320 and BC-550), at three different temperatures (10, 30 and 50 °C) were analyzed using Langmuir and Freundlich isotherm models, while pseudo-first order, pseudo-second order and intra-particle diffusions models were used to model the kinetic data. The biosorption of Cu(II) ions is best described by the Langmuir model and the pseudo-second kinetic model, regardless of the type of biosorbent. Such behavior is characteristic for the retention of metal ions on low-cost materials, and is explained in the literature using the concepts of molecular symmetry. The maximum biosorption capacity (qmax, mg/g) depends on the temperature, but also on the type of biosorbent, and follow the order: BC-320 < AB < BC-550. Using the experimental isotherms, the thermodynamic parameters (ΔG0, ΔH0 and ΔS0) for the biosorption of Cu(II) ions on each biosorbent were calculated. The analysis of the obtained values constitutes the main arguments in choosing BC-550 as the most effective biosorbent for the removal of Cu(II) ions from aqueous media.

Removal of Copper Ions onto Walnut Shells by Using Batch and Continuous Fluidized Bed

An agricultural waste (walnut shell) was undertaken to remove Cu(II) from aqueous solutions in batch and continuous fluidized bed processes. Walnut shell was found to be effective in batch reaching 75.55% at 20 and 200 rpm, when pH of the solution adjusted to 7. The equilibrium was achieved after 6 h of contacting time. The maximum uptake was 11.94mg/g. The isotherm models indicated that the highest determination coefficient belongs to Langmuir model. Cu (II) uptake process in kinetic rate model followed the pseudo-second-order with determination coefficient of 0.9972. More than 95% of the Cu(II) were adsorbed on the walnut shells within 6 h at optimum agitation speed of 800 rpm. The main functional groups responsible for biosorption of Cu(II) onto walnut shell were hydroxyl, carbonyl,carboxylate, carboxylic acids, alcohols groups, and aromatic compounds. In continuous system, fluidized bed column at 20 , and pH 7 was carried out to study the effects of various parameters like (flow rate,bed depth, and initial concentration). The time of breakthrough was 97 min when the initial concentration (Co= 20mg/l), bed depth (L=10cm), and flowrate (Q=10l/h)

Immobilization of Pseudomonas aeruginosa FNCC-0063 on Calcium Alginate and Its Application as Bioabsorbent

Biosorption of Cu (II) using bacteria Pseudomonas aeruginosa FNCC-0063 was immobilized on calcium alginate (PAI). This research examined the effect of various parameters such as pH, contact time, and initial Cu (II) concentration. The biosorption mechanism of Cu (II) was studied by sequential desorption with H2O, KNO3 1 M, HNO3 0.5 M and Na2EDTA 0.1 M. Cu (II) concentration was analyzed using atomic absorption spectrophotometer (AAS). The results showed that optimum Cu (II) ion biosorption occurred at a pH biosorption rate constant of 0.03724 g mg-1.min-1. The kinetics studies showed that Cu (II) biosorption follows pseudo-second-order. The biosorption capacities of 36.60 mg/g. Cu (II) Biosorption followed the Freundlich equation, as shown by a high correlation coefficient (R2) of about 0.99. Ionic bonds dominated the biosorption mechanism of Cu (II) ion on immobilized PAI.

Hybrid biosorbents from exopolymeric substances immobilized in Ca-alginate and their biosorption mechanisms in single and multi-metal systems

ABSTRACT This study developed a hybrid biosorbent consisting of exopolymeric substances (EPS) from Bacillus cereus immobilized in the gelling agent Ca-alginate. Metal removal tests revealed that the hybrid EPS beads showed significantly higher metal removal compared to plain alginate beads. This higher removal efficacy in hybrid biosorbents was attributed to the increased number of functional groups detected via FTIR analysis. Hybrid EPS beads bind metals via the formation of strong covalent bonds (chemisorption), rather than through weak van der Waals forces (physisorption), complying with the pseudo-second order model. This was consistent in both single and multi-metal systems. For adsorption isotherm, metal removal (pH 5, 25ºC, 120 rpm) by hybrid biosorbents in single metal systems fits the Langmuir isotherm (monolayer adsorption). In multi-metal systems, however, the removal of Zn and Cd demonstrated a better fit to the Freundlich isotherm (multilayer adsorption) compared to the typical Langmuir isotherm (for Cu, Pb and Cr). The isotherm models indicated that the maximum biosorption capacity for Cu, Pb, Zn, Cd and Cr was at 34.97, 156.24, 19.19, 11.66 and 38.61 mg g−1, respectively. The hybrid EPS beads are superior for the biosorption of Cu, Pb and Cr compared to existing biosorbents.

Biocomposite based on N-maleated chitosan immobilized in amino-carbamated alginate matrix for effective biosorption of Cu(II)

Abstract Synthesis of a biocomposite based on N-maleated chitosan immobilized in amino-carbamated alginate matrix (NMC-PSC) was carried out. Facile chemical modifications of sodium alginate and chitosan were executed using maleic anhydride and 4-phenylsemicarbazide as chemical modifiers, respectively. NMC-PSC hydrogel beads were employed for Cu(II) biosorption from aqueous media. Study of surface characterization, morphology and chemical structure of the sorbent indicated the successful surface functionalization and attachment of Cu(II) ions. Sorption parameters like pH, time of contact, sorbent dosage and adsorbate content significantly influenced the sorption capacity. Kinetic results demonstrated that copper sorption on NMC-PSC was governed by chemisorption and ion-exchange rather than merely mass transfer. Equilibrium sorption data closely fitted with Langmuir model and maximum Langmuir monolayer binding capacity (q m ) was determined as 207 mg/g. The negative ΔG o values indicated the spontaneity of Cu(II) sorption process while ΔH o and ΔS o parameters indicated the exothermic nature of sorption which proceeds with rise in entropy.

Walnut shells as a potential biosorbent for Cu(II), Pb(II) and As(III)/(V) ions removal from river waters

In this study, the potential of the walnut shell as a biosorbent for biosorption of Cu(II), Pb(II), and As(III)/(V) ions from river water samples was investigated. The effects of various conditions of water samples such as the initial ion concentration, sample pH, and contact time at a constant temperature and biosorbent dosage, on biosorption of Cu(II), Pb(II), and As(III)/(V) were investigated. Walnut shells, as the material with a high potential for removal of investigated ions, have biosorption efficiency of up to 99.6%, under the applied experimental conditions. The best adsorption time was obtained at 4 h for Cu(II), Pb(II), and As(III)/(V) ions. The maximum removal of 97.6% (Cu(II)), 82.9% (Pb(II)), and 99.6% (As(III)/(V)) was obtained at pH=4.43, pH=8.55, and pH=7.84, respectively. Hence, the walnut shell shows potential of a cost-effective biosorbent that could be used for the treatment of contaminated rivers. However, further investigation is needed to fully explore this potential.

Copper Adsorption Potentiality of Bacillus stercoris GKSM6 and Pseudomonas alcaliphila GKSM11 Isolated from Singhbhum Copper Mines

Increasing industrial activities, mining deposits, excessive use of hazardous chemicals, and waste discharges are the driving forces for emerging copper (Cu) contamination. In the present study, two highly Cu-tolerant bacterial isolates, Bacillus stercoris GKSM6 and Pseudomonas alcaliphila GKSM11, were isolated, characterized, and investigated for their copper sorption potential. The Cu2+ tolerable concentrations were found to be 350 mg/L for strain GKSM6 and 400 mg/L for strain GKSM11. The maximum copper uptake capacity of GKSM6 was found to be 35.05 mg/g, whereas it was 31.15 mg/g in case of GKSM11 at optimum conditions of pH 7.0, temperature 35 °C for 24 h. The equilibrium data was well fitted with the Langmuir isotherm model (R 2 = 0.9851 for B. stercoris and R 2 = 0.9954 for P. alcaliphila), indicating a homogenous monolayer adsorption pattern. Electron microscopic analysis confirmed the immobilization of copper ions on the bacterial cell surface. The EDS peak also showed the surface sorption of copper ions, which was confirmed by the presence of various functional groups like carboxyl, hydroxyl, amine, and phosphate. In this prospect, the novelty of this study relies on the biosorption of Cu2+ using Singhbhum copper mines inhabiting bacterial isolates pay as a possible option for the amelioration of copper-contaminated sites.

Adsorption of Copper and Lead Ions in a Binary System onto Orange Peels: Optimization, Equilibrium, and Kinetic Study

Agricultural waste materials have been proven to be efficient for heavy metal sequestration from wastewater. In this paper, the interactive effects of initial concentration, adsorbent dosage, and particle size on the removal of copper and lead ions in a binary system onto orange peels were investigated using a central composite design. The pHpzc of orange peels was determined to be 3.85. The Fourier transform infrared (FTIR) and energy dispersive x-ray (EDX) revealed the functional groups and elemental composition present on the surface of the bio-sorbent, respectively, before and after adsorption. The ANOVA showed a good fit with a coefficient of determination (R2) of 0.973 and 0.993 for Cu and Pb, respectively. The bio-sorption of Cu and Pb increased with increasing adsorbent dosage while the percentage removal of Pb was consistently higher than Cu. The highest percentage removal of Cu and Pb gave 86.27% and 98.85%, respectively. The kinetic and isotherm studies showed that pseudo-second-order and Langmuir isotherm models fitted the experimental data suggesting chemisorption and monolayer adsorption, respectively. The treatment of wastewater is very essential to avoid water scarcity and to achieve the Sustainable Development Goals (SDGs). This study demonstrates the potential of utilizing orange peels as bio-sorbent for the treatment of wastewater containing Cu and Pb ions.

Effective biosorption of Cu(II) using hybrid biocomposite based on N-maleated chitosan/calcium alginate/titania: Equilibrium sorption, kinetic and thermodynamic studies

In this research work, a hybrid biocomposite based on N-maleated chitosan, amino-thiocarbamate functionalised calcium alginate and anhydrous Titania nanoparticles (NMC-MCA-TiO2) was fabricated. The study involves the one pot facile synthesis of N-maleated chitosan and amino-thiocarbamate functionalised alginate under moderate conditions. Sorbent was conditioned in the form of hydrogel beads and characterized through FT-IR and SEM analysis. Newly grafted functional groups could act as potential chelating sites for enhanced Cu(II) sorption. Modified biopolymers were organo-functionalised which provided excellent support for immobilization of Titania nanoparticles (TiO2) as inorganic filler. Kinetic data illustrated the manifestation of intrinsic chemisorption instead of simple bulk/film diffusion. Equilibrium sorption data fitted well with Freundlich adsorption model (R2 ≈ 0.99) which designated the heterogeneous nature of sorbent. Maximum sorption capacity of biosorbent was found 192 mg/g at 298 K and pH = 6.0. Standard Gibbs free energy change ∆Go (−21.53, −21.97, and − 22.42 kJ/mol), standard enthalpy change ∆Ho (5.12 kJ/mol) and standard entropy change ∆So (0.09 kJ/mol K−1) values suggested that the sorption process to be spontaneous and endothermic. The sorbent 3NMC-MCA-TiO2 could be competitive candidate for economical and rapid adsorptive removal of Cu(II) from dilute contaminated liquids.

Copper(II) ion removal by chemically and physically modified sawdust biochar

The difference between physical activations (by sonications) and chemical activations (by ammonia) on sawdust biochar has been investigated in this study by comparing the removal of Cu(II) ions from an aqueous medium by adsorption on sawdust biochar (SD), sonicated sawdust biochar (SSD), and ammonia-modified sawdust biochar (SDA) with stirring at room temperature, pH value of 5.5–6.0, and 200 rpm. The biochar was prepared by the dehydrations of wood sawdust by reflux with sulfuric acid, and the biochar formed has been activated physically by sonications and chemically by ammonia solutions and then characterized by the Fourier transform infrared (FTIR); Brunauer, Emmett, and Teller (BET); scanning electron microscope (SEM); thermal gravimetric analysis (TGA); and energy-dispersive spectroscopy (EDX) analyses. The removal of Cu(II) ions involves 100 mL of sample volume and initial Cu(II) ion concentrations (conc) 50, 75, 100, 125, 150, 175, and 200 mg L−1 and the biochar doses of 100, 150, 200, 250, and 300 mg. The maximum removal percentage of Cu(II) ions was 95.56, 96.67, and 98.33% for SD, SSD, and SDA biochars, respectively, for 50 mg L−1 Cu(II) ion initial conc and 1.0 g L−1 adsorbent dose. The correlation coefficient (R2) was used to confirm the data obtained from the isotherm models. The Langmuir isotherm model was best fitted to the experimental data of SD, SSD, and SDA. The maximum adsorption capacities (Qm) of SD, SSD, and SDA are 91.74, 112.36, and 133.33 mg g−1, respectively. The degree of fitting using the non-linear isotherm models was in the sequence of Langmuir (LNR) (ideal fit) > Freundlich (FRH) > Temkin (SD and SSD) and FRH (ideal fit) > LNR > Temkin (SDA). LNR and FRH ideally described the biosorption of Cu(II) ions to SD and SSD and SDA owing to the low values of χ2 and R2 obtained using the non-linear isotherm models. The adsorption rate was well-ordered by the pseudo-second-order (PSO) rate models. Finally, chemically modified biochar with ammonia solutions (SDA) enhances the Cu(II) ions’ adsorption efficiency more than physical activations by sonications (SSD). Response surface methodology (RSM) optimization analysis was studied for the removal of Cu(II) ions using SD, SSD, and SDA biochars.

Kinetics, Isotherm and Thermodynamic Studies of the Reclusion of Cu (II) from Aqueous Solution by Maize Cob and Sugarcane Pulp

Over the years, heavy metal contamination of the environment, through industrial waste had been a perennial problem to which biosorption is being proposed as solution in recent studies. The biosorption characteristics of Cu (II) ion using maize and saccharumofficinarum (sugarcane pulp) were investigated by contacting 0.5g of the biomass with 10ml of 100mg/L solution of the metal ions. Experimental parameters affecting the biosorption process such as pH, contact time, concentration and temperature were studied. Langmuir and Freundlich models were applied to describe the biosorption isotherms. The biosorption capacities of maize cob and saccharumofficinarum were found to be sufficiently high to consider the biomasses used as substances that could be employed in the removal of Cu (II) ions from waste water. The calculated thermodynamic parameters, G 0 , for biosorption of Cu (II) on to cob and bagasse determine at pH 5.0 and 301k, are -1.5KJmol -1 and -2.505KJmol -1 respectively. This showed that the biosorption of Cu (II) ions onto maize cob and saccharumofficinarum was feasible and spontaneous at 301K.

Biosorption of Cu(II) ions as a method for the effective use of activated carbon from grape stalk waste: RMS optimization and kinetic studies

ABSTRACT This study was undertaken to examine the effect of such biosorption factors as initial Cu(II) concentration, biosorbent dosage, reaction temperature, contact time and mixing speed on the efficiency of removal Cu(II) ions from wastewater using activated carbon from grape stalk waste. In this case, Response Surface Methodology (RSM) was used in conjunction with a Box–Behnken design of experiments to predict the final Cu(II) concentration (CFin ), while considering the previously mentioned biosorption factors. In an attempt to obtain the maximum removal of final Cu(II) concentration, while minimizing energy consumption, the Multi-Response Surface Methodology (MRS) was used. Three possible optimizations were proposed for the maximum elimination of final Cu(II) in this case. The maximum (100 mg/L), minimum (2 mg/L) and intermediate (51 mg/L) values of the study were used for the initial Cu(II) concentration. The optimal values that were reached were 92.21% when the initial copper concentration was 51 mg/L and the activated carbon dose, temperature, mixing speed and reaction time, were, respectively, 0.895 g/L, 20.036°C, 105.313 rpm and 30.181 s. Also, in regard to thermodynamic studies, the experimental equilibrium data provided a good fit using the Freundlich model, whereas the kinetic data were efficiently by the pseudo-second order. These results support the use of grape stalk waste in the production of activated carbon for the removal of Cu(II) ions from water. This could help to improve the economics of treating wastewater.

Harnessing the Potential of Bacillus altitudinis MT422188 for Copper Bioremediation.

The contamination of heavy metals is a cause of environmental concern across the globe, as their increasing levels can pose a significant risk to our natural ecosystems and public health. The present study was aimed to evaluate the ability of a copper (Cu)-resistant bacterium, characterized as Bacillus altitudinis MT422188, to remove Cu from contaminated industrial wastewater. Optimum growth was observed at 37°C, pH 7, and 1 mm phosphate, respectively. Effective concentration 50 (EC50), minimum inhibitory concentration (MIC), and cross-heavy metal resistance pattern were observed at 5.56 mm, 20 mm, and Ni > Zn > Cr > Pb > Ag > Hg, respectively. Biosorption of Cu by live and dead bacterial cells in its presence and inhibitors 1 and 2 (DNP and DCCD) was suggestive of an ATP-independent efflux system. B. altitudinis MT422188 was also able to remove 73 mg/l and 82 mg/l of Cu at 4th and 8th day intervals from wastewater, respectively. The presence of Cu resulted in increased GR (0.004 ± 0.002 Ug−1FW), SOD (0.160 ± 0.005 Ug−1FW), and POX (0.061 ± 0.004 Ug−1FW) activity. Positive motility (swimming, swarming, twitching) and chemotactic behavior demonstrated Cu as a chemoattractant for the cells. Metallothionein (MT) expression in the presence of Cu was also observed by SDS-PAGE. Adsorption isotherm and pseudo-kinetic-order studies suggested Cu biosorption to follow Freundlich isotherm as well as second-order kinetic model, respectively. Thermodynamic parameters such as Gibbs free energy (∆G°), change in enthalpy (∆H° = 10.431 kJ/mol), and entropy (∆S° = 0.0006 kJ/mol/K) depicted the biosorption process to a feasible, endothermic reaction. Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Energy-Dispersive X-Ray Spectroscopy (EDX) analyses revealed the physiochemical and morphological changes in the bacterial cell after biosorption, indicating interaction of Cu ions with its functional groups. Therefore, these features suggest the potentially effective role of B. altitudinis MT422188 in Cu bioremediation.

Integrative chemical and omics analyses reveal copper biosorption and tolerance mechanisms of Bacillus cereus strain T6

A comprehensive understanding of the cellular response of microbes to metal stress is necessary for the rational development of microbe-based biosorbents for metal removal. The present study investigated the copper (Cu) sorption and resistance mechanism of Bacillus cereus strain T6, a newly isolated Cu-resistant bacterium, by integrative analyses of physiochemistry, genomics, transcriptomics, and metabolomics. The growth inhibition assay and biosorption determination showed that this bacterium exhibited high tolerance to Cu, with a minimum inhibitory concentration of 4.0 mM, and accumulated Cu by both extracellular adsorption and intracellular binding. SEM microscopic images and FTIR spectra showed significant cellular surface changes at the high Cu level but not at low, and the involvement of surface functional groups in the biosorption of Cu, respectively. Transcriptomic and untargeted metabolomic analyses detected 362 differentially expressed genes and 60 significantly altered metabolites, respectively. Integrative omics analyses revealed that Cu exposure dramatically induced a broad spectrum of genes involved in Cu transport and iron homeostasis, and suppressed the denitrification pathway, leading to significant accumulation of metabolites for metal transporter synthesis, membrane remolding, and antioxidant activities. The results presented here provide a new perspective on the intricate regulatory network of Cu homeostasis in bacteria.