Exopolymeric substances production by Bacillus cereus KMS3-1 enhanced its biosorption efficiency in removing Cd2+ and Pb2+ in single and binary metal mixtures.

The present study investigated the growth, exopolymeric substance (EPS) production, and biosorption efficiency of strain Bacillus cereus KMS3-1 in the Cd2+ and Pb2+ ions containing single and binary metal-treated broth (50 mg/L). In addition, the interaction of the KMS3-1 strain with Cd2+ and Pb2+ ions in single and binary metal-treated broths was investigated using SEM-EDS, FTIR, and XRD analyses. The results showed that the biosorption efficiency (%) and EPS production of KMS3-1 biomass in both single and binary metal-treated broths had increased with increasing incubation time and were higher for Pb2+ ions than for Cd2+ ions. In the single and binary metal-treated broths, the maximum biosorption efficiency of KMS3-1 for Pb2+ ions were 70.8% and 46.3%, respectively, while for Cd2+ ions, they were 29.3% and 16.8%, respectively, after 72 h. Moreover, the biosorption efficiency of strain KMS3-1 for both metal ions was dependent on its EPS production and peaked at the maximum EPS production. The copious EPS production by KMS3-1 was observed in metal-treated media (50 mg/L), in the following order: Pb2+ ions (1925.7 µg/mL) > binary metal mixtures (1286.8 µg/mL) > Cd2+ ions (1185.5 µg/mL), > control (1099 µg/mL) after 72 h of incubation. This result indicates that the metal biosorption efficiency of the KMS3-1 strain was enhanced by the increased EPS production in the surrounding metal-treated broth. SEM-EDS and FTIR characterization studies revealed that the KMS3-1 biomass effectively adsorbed Cd2+ and Pb2+ ions from the medium by interacting with their surface functional groups (hydroxyl, carbonyl, carboxyl, amide, and phosphate). Moreover, the biosorbed Cd2+ and Pb2+ ions were transformed into CdS and PbS, respectively, by the KMS3-1 biomass. This study suggests that the Bacillus cereus KMS3-1 strain may be a promising candidate for the treatment of metal contamination.

Microbial degradation of low-density polyethylene (LDPE) and polystyrene using Bacillus cereus (OR268710) isolated from plastic-polluted tropical coastal environment.

The study focused on marine bacteria, specifically Bacillus cereus, sourced from heavily polluted coastal areas in Tamil Nadu, aiming to assess their efficacy in degrading low-density polyethylene (LDPE) and polystyrene over a 42-day period. When LDPE and polystyrene films were incubated with Bacillus cereus, they exhibited maximum weight losses of 4.13 ± 0.81 % and 14.13 ± 2.41 %, respectively. Notably, polystyrene exhibited a higher reduction rate (0.0036 day-1) and a shorter half-life (195.29 days). SEM images of the treated LDPE and polystyrene unveiled surface erosion with cracks. The energy dispersive X-ray (EDX) analysis revealed elevated carbon content and the presence of oxygen in the treated LDPE and polystyrene films. The ATR-FTIR spectra exhibited distinctive peaks corresponding to functional groups, with observable peak shifts in the treated films. Notable increases were detected in carbonyl, internal double bond, and vinyl indices across all treated groups. Additionally, both treated LDPE and polystyrene showed reduced crystallinity. This research sheds light on Bacillus cereus (OR268710) biodegradation capabilities, emphasizing its potential for eco-friendly waste management in coastal regions.

Ecological risk assessment of metals in the Arctic environment with emphasis on Kongsfjorden Fjord and freshwater lakes of Ny-Ålesund, Svalbard.

The concentrations of five heavy metals (Cd, Cr, Cu, Pb, and Zn) in the sediments, water, phytoplankton, zooplankton, and macroalgae from Kongsfjorden Fjord and the freshwater lakes of Ny-Ålesund in the Svalbard archipelago were determined in order to describe the anthropogenic impacts related to the Ny-Ålesund town. Water samples from nine stations, sediment samples from 23 stations, plankton samples from five stations, and six species of macroalgae were collected and subjected to heavy metal analysis using atomic absorption spectrophotometry (AAS). Only Cu and Zn were detected in the water samples. The plankton samples had only Zn, Cu, and Cr. The average metal concentrations in macroalgae fell in the decreasing order of Cu > Zn > Cr > Cd > Pb. In sediment samples, the metal order was as follows: Zn > Cu > Cr > Pb > Cd. Multivariate statistical analyses including principal component analysis (PCA) and hierarchical cluster analysis (HCA) were used to identify the source of the metal contamination. The metals were found to originate from a blend of both anthropogenic and geogenic sources. Pollution monitoring indices including geoaccumulation index (Igeo), contamination factor, contamination degree (Cdeg), pollution load index (PLI), and potential ecological risk (PER) were calculated using the metal data. In the study area, Igeo values of the metals showed pollution grades from 0 (uncontaminated) to 6 (extremely contaminated). Cdeg fell in classes from 1 (low contamination) to 4 (very high contamination). PLI values ranged between 0 and 5.68. PER values expressed that except for a few stations located at higher elevations in the glacial outwash plains, all other sites were highly polluted. The high level of pollution indices in the sites can be attributed to the anthropogenic activities persistent in the study area.

Survey to identify the metal accumulation pathway in humans using hair and nail as biomarkers from fisherfolk population.

Human hair and nail samples from Cuddalore fisherfolk populations were used as biomarkers for assessing metal concentrations in humans. Hair samples from 80 participants (47 men and 33 women) and nail samples from 40 participants (21 men and 19 women) were collected, and the concentrations of Cd, Cu, Pb, and Zn were assessed using an atomic absorption spectrophotometer (AAS). Metal data from AAS were compared with the survey questionnaire's personal and dietary parameters. Results indicate that both personal and dietary parameters may influence metal exposure; however, majority of the sources may have originated from metal-contaminated seafood. Higher metal accumulation in communities, especially those which consume seafood on a daily basis, may increase the possibility for them to get affected by metal-related diseases. Based on environmental parameters, people who live ≤500 m from industrial zones accumulate more metals. Further extensive studies with more individuals and more questionnaire parameters are needed to identify the metal accumulation pathway in humans.