Scaling EPS yield and bio-carrier application of Bacillus paralicheniformis UB08 for rapid lead remediation

Integrated nitrate bioremediation and microbial risk mitigation using Bacillus pacificus

Ureolytic Lysinibacillus sp. exhibiting Calcium Carbonate Precipitation with Effective Lead (Pb) Removal

Industrial effluents contaminated with heavy metals are a major environmental issue, prompting the need for sustainable bioremediation methods. Microbially induced calcium carbonate precipitation (MICP) is a remediation method that offers a long-term solution for enhancing soil mechanical properties, as well as reducing pollution from heavy metals. The objectives of the current study include screening and identifying native ureolytic bacteria from soil in Karad, as well as assessing calcite precipitation by ureolytic metallotolerant bacteria. The effectiveness of the isolated bacteria in removing lead as a heavy metal was tested in the medium. This research focuses on the removal of Pb heavy metal by using the MICP method. Samples of wastewater were taken from calcareous soils and effluents contaminated with heavy metals. Ureolytic bacteria were identified using urea agar medium and nine positive isolates were obtained by using Christensen’s media. Ureolytic isolates were then screened for their tolerance to metal Pb²⁺ as well as calcium precipitation. The maximum tolerance ranged from 2 mM to 8 mM, depending on the metal ion. The potential isolate was identified through 16S rRNA gene sequencing. Lysinibacillus fusiformis was recognized as a urease-producing, metallotolerant bacterium with calcium precipitation. By using Lysinibacillus fusiformis, 86.04 % of the lead was removed. This is to evaluate Lysinibacillus-mediated MICP for Pb bioremediation from under environmentally relevant conditions, treated for real wastewater applications.

Kinetic study of glyphosate biodegradation by actinobacterial consortium RH1: implications for bioremediation

Background The excessive use of glyphosate herbicide in agriculture adversely affects the environment and soil health. Bioremediation using microbial consortia offers an efficient approach for transforming pesticides into less harmful products. Objectives The study investigated glyphosate biodegradation by the RH1 consortium and identified suitable kinetic models to support bioremediation. Methods Glyphosate biodegradation was investigated at concentrations of 1–200 mg/L using the RH1 microbial consortium comprising four Streptomyces strains (SPA2, IT, Herb, and SC). These strains had been previously isolated and validated for their individual glyphosate-degrading capacity. Consortium activity was assessed under optimized conditions (30 °C, pH 7.2, and 4% inoculum). Degradation kinetics were modeled using several established approaches, including Haldane–Andrews, Yano and Koga, Tseng and Wayman, and Webb. Comparative functional analysis was further performed at 50 mg/L using total organic carbon (TOC) quantification and ATR-FTIR spectroscopy to distinguish consortium performance relative to single-strain treatments. Results Following 15 days of incubation under optimized conditions, the RH1 consortium achieved high glyphosate removal efficiencies of 92.2%, 87.2%, 91.72%, 92.06%, 54.11%, and 37.085% at initial concentrations of 1, 10, 25, 50, 100, and 200 mg/L, respectively. Notably, at 50 mg/L the consortium demonstrated the highest degradation rate compared with pure-culture treatments. Kinetic evaluation indicated that the Haldane–Andrews model best described the degradation behavior (F = 65.49, P = 0.00074, R 2 = 0.976). At the same concentration (50 mg/L), total organic carbon (TOC) decreased by 91.03%, corroborating substantial mineralization or conversion of organic constituents. ATR-FTIR spectroscopy further confirmed glyphosate transformation by showing alterations in the pesticide’s chemical bonding patterns after biodegradation, consistent with structural modification of the molecule. Conclusion The RH1 actinobacterial consortium efficiently degraded glyphosate, fitting best to the Haldane–Andrews kinetic model. Significant TOC reduction and ATR-FTIR–confirmed structural changes indicate effective glyphosate transformation, highlighting RH1’s potential for bioremediation of glyphosate-contaminated soils.

Valorization of different agricultural wastes for yeast based Reactive Black 5 bioaccumulation.

The textile industry generates large volumes of dye-laden effluents that pose risks to aquatic ecosystems and human health. This study evaluates the bioaccumulation of Reactive Black 5 (RB5) using Candida boidinii and Kluyveromyces marxianus yeast strains. Key operational parameters including initial pH, incubation time, dye concentration, and microbial growth were systematically investigated. In addition, the effects of low-cost agricultural wastes-carrot pomace (CP), industrial tea waste (ITW), and pumpkin pomace (PP)-as supplementary substrates were compared. Results showed that CP was the most effective substrate, with 100 g/L CP significantly enhancing RB5 removal. At pH 5.0 and 50 mg/L RB5, removal efficiencies reached 96.88% for C. boidinii and 81.76% for K. marxianus with CP, compared to 72.90% and 65.07% with PP. Although removal efficiency decreased at higher dye concentrations, the maximum dye uptake capacity (qm) increased with initial RB5 concentration, reaching 52.52 mg/g for C. boidinii and 33.23 mg/g for K. marxianus over the tested range (≈50-600 mg/L). To our knowledge, this is the first report demonstrating RB5 removal by these yeasts using CP as a low-cost substrate. Overall, CP significantly improves yeast-based RB5 bioaccumulation and represents a promising, sustainable option for treating dye-contaminated wastewater.

Characterization of Biosurfactants Produced by a Novel Hydrocarbonoclastic Bacterial Strain Rhodococcus ruber N19 Isolated From River Sediment

Biosurfactants are eco‐friendly, surface‐active compounds produced by microorganisms that have significant industrial and environmental applications due to their biodegradability and low toxicity. This study focuses on the production and characterization of biosurfactants by bacterial strain N19, a novel hydrocarbonoclastic bacterium isolated from Soummam River sediment. The bacterium was cultured in mineral salt medium supplemented with crude oil to stimulate biosurfactant production. Surface tension reduction (23.14 ± 0.12 mN/m), emulsification index (72.13% ± 1.15%), and oil displacement (4.2 ± 0.75 cm) tests confirmed the presence of an effective biosurfactant. Further phenotypic and molecular identification methods, including 16S rRNA sequencing, established the strain's identity as Rhodococcus ruber N19. This strain produced 7.92 ± 0.02 mg/mL biosurfactant. Structural characterization using thin layer chromatography (TLC), Fourier‐transform infrared (FTIR) spectroscopy, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF/MS), and liquid chromatography–tandem mass spectrometry (LC–MS/MS), and nuclear magnetic resonance (NMR) analyses revealed that the biosurfactant produced by this strain is a lipopeptide. The nonhemolytic properties, combined with the ability to lower surface tension and exhibit strong emulsification and oil displacement activities, highlight the potential of this biosurfactant for bioremediation, petroleum industry applications, and biomedical use.

Bioremediation and heavy metal recovery from e-waste through enrichment and identification of effective bacterial isolates