scholarly journals Exploration of an Extracellular Polymeric Substance from Earthworm Gut Bacterium (Bacillus licheniformis) for Bioflocculation and Heavy Metal Removal Potential

2020 ◽  
Vol 10 (1) ◽  
pp. 349 ◽  
Author(s):  
Jayanta Kumar Biswas ◽  
Anurupa Banerjee ◽  
Binoy Sarkar ◽  
Dibyendu Sarkar ◽  
Santosh Kumar Sarkar ◽  
...  

The present study shows the potential of an extracellular polymeric substance (EPS) produced by Bacillus licheniformis strain KX657843 isolated from earthworm (Metaphire posthuma) gut in the sorption of Cu(II) and Zn(II) and in flocculation. After harvesting bacterial cells from sucrose supplemented denitrifying culture medium, the EPS was extracted following ethanolic extraction method. The Fourier Transform Infrared Spectroscopy (FTIR) and 1H and 13C Nuclear Magnetic Resonance (NMR) of EPS revealed its functional groups, electronegative constituents, unsaturated carbon, and carbonyl groups. The negatively charged functional groups of carbohydrates and protein moiety of the EPS endowed it with heavy metal binding capacity through electrostatic interactions. The highest flocculation activity (83%) of EPS was observed at 4 mg L−1 and pH 11. The metal sorption by EPS increased with increasing pH. At pH 8, the EPS was able to remove 86 and 81% Cu(II) and Zn(II), respectively, from a 25 mg L−1 metal solution. 94.8% of both the metals at 25 mg L−1 metal solutions were removed by EPS at EPS concentration of 100 mg L−1. From Langmuir isotherm model, the maximum sorption capacities of EPS were calculated to be 58.82 mg g−1 for Cu(II) and 52.45 mg g−1 for Zn(II). The bacterial EPS showed encouraging flocculating and metal sorption properties. The potential to remove Cu(II) and Zn(II) implies that the EPS obtained from the earthworm gut bacteria can be used as an effective agent for environmental remediation of heavy metals and in bioflocculation.

Author(s):  
Anuradha Mulik ◽  
Rama Bhadekar

Objective: Evaluation of Extracellular Polymeric Substance (EPS) induced heavy metal tolerance in Kocuria sp. BRI 36.Methods: Initially, the effect of different concentrations of glucose (1-10 %) on EPS production by BRI 36 was examined. At optimum glucose concentrations, EPS levels were measured by varying heavy metal concentrations (10-50 ppm) of Pb2+, Cd 2+and Cr3+. Maximum tolerable concentration (MTC) and survival percentage of BRI 36 were determined under conditions that support EPS synthesis. Comparative analysis of extracted crude EPS was performed by Fourier Transform Infrared Spectroscopy (FTIR) to establish functional groups involved in the metal interaction. Results: Kocuriasp. BRI 36 produced maximum EPS (1g/l) at 5% glucose. Increase in EPS production up to 89% (considering 1g/l as 100%) with an increase in concentrations of heavy metals up to 40 ppm. MTC levels of BRI 36 for heavy metals increased up to 700 ppm when it was cultivated in presence of 5% glucose indicating a major role of surface polymer in metal adsorption. The function of EPS as a protective cover was also evident from an increase in survival percentage of BRI 36 up to 39.4 at MTC. Comparative analysis of extracted crude EPS by FTIR revealed the involvement of O-H, C=O, and C-O-C groups in metal adsorptionConclusion: Antarctic oceanic isolate Kocuria sp. BRI 36 has an ability to produced EPS under stress conditions of heavy metals. Simultaneously, its MTC values increased due to increase in EPS levels. These observations suggest the possibility to develop gentle, environmentally safe and cost-effective method for heavy metal removal.


2001 ◽  
Vol 36 (4) ◽  
pp. 793-803 ◽  
Author(s):  
Tadeusz Skowroński ◽  
Jacek Pirszel ◽  
Barbara Pawlik Skowrońska

Abstract Metal sorption capacity of the granulated biosorbent derived from the waste biomass of Penicillium chrysogenum was examined. The potential metal sorption abilities of the biosorbent were estimated as the cation-exchange capacity, using a potentiometric titration. The total binding capacity, calculated for the pH range 3 to 8 was about 511 µeq/g dry weight. The granular biosorbent was capable of Cd, Zn, Cu and Pb binding. The kinetics of the heavy metal sorption were typical of the microbial dead biomass; metals were bound in the first few minutes. Sorption was a saturable process and the maximum sorption capacity, calculated from the Langmuir equation for the particular heavy metals was: 96 mg Pb; 21.5 mg Cd; 13 mg Zn and 11.7 mg Cu (per g dry weight). Optimum pH values for Cd, Zn and Cu sorption were about 7, while for Pb about 6. Heavy metal removal from different solutions was examined using the biosorption columns packed with P. chrysogenum, which efficiently removed Cd from 1 mM Cd solution, or Cd and Zn from the industrial wastewater. The studied biosorbent was capable of accumulating Cd and Zn even at the high Ca concentration.


Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1559
Author(s):  
Ida Sylwan ◽  
Hanna Runtti ◽  
Lena Johansson Westholm ◽  
Henrik Romar ◽  
Eva Thorin

Municipal wastewater management causes metal exposure to humans and the environment. Targeted metal removal is suggested to reduce metal loads during sludge reuse and release of effluent to receiving waters. Biochar is considered a low-cost sorbent with high sorption capacity for heavy metals. In this study, heavy metal sorption to sludge-derived biochar (SDBC) was investigated through batch experiments and modeling and compared to that of wood-derived biochar (WDBC) and activated carbon (AC). The aim was to investigate the sorption efficiency at metal concentrations comparable to those in municipal wastewater (<1 mg/L), for which experimental data are lacking and isotherm models have not been verified in previous works. Pb2+ removal of up to 83% was demonstrated at concentrations comparable to those in municipal wastewater, at pH 2. SDBC showed superior Pb2+ sorption capacity (maximum ~2 mg/g at pH 2) compared to WDBC and AC (<0 and (3.5 ± 0.4) × 10−3 mg/g, respectively); however, at the lowest concentration investigated (0.005 mg/L), SDBC released Pb2+. The potential risk of release of other heavy metals (i.e., Ni, Cd, Cu, and Zn) needs to be further examined. The sorption capacity of SDBC over a metal concentration span of 0.005–150 mg Pb2+/L could be predicted with the Redlich–Peterson model. It was shown that experimental data at concentrations comparable to those in municipal wastewater are necessary to accurately model and predict the sorption capacity of SDBC at these concentrations.


RSC Advances ◽  
2016 ◽  
Vol 6 (108) ◽  
pp. 106600-106607 ◽  
Author(s):  
Na Li ◽  
Yanzhuo Pan ◽  
Na Zhang ◽  
Xueyan Wang ◽  
Weizhi Zhou

A novel isolated bacteriumPseudoalteromonassp. CF10-13 could reduce Cr(vi) to Cr(iii) by periplasic reductase with Cr(iii) bound to functional groups in extracellular polymeric substance (EPS) or leached to media as soulbe organic-Cr(iii).


RSC Advances ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 1274-1280 ◽  
Author(s):  
Liang Wu ◽  
Xingrong Zhang ◽  
Long Chen ◽  
Huan Zhang ◽  
Chengbi Li ◽  
...  

A pH-responsive starch-based flocculants containing both cationic and anionic functional groups has been developed. The saturated flocculant can be facilely regenerated and separated from the solution by applying an external pH stimulus.


Sign in / Sign up

Export Citation Format

Share Document