scholarly journals Characterization of Bacillus nealsonii strain KBH10 capable of reducing aqueous mercury in lab-scale reactor

Author(s):  
Asifa Farooqi ◽  
Ghufranud Din ◽  
Rameesha Hayat ◽  
Malik Badshah ◽  
Samiullah Khan ◽  
...  

Abstract The environmental release of Mercury is continuously increasing with high degree of mobility, transformation and amplified toxicity. Improving remediation strategies is becoming increasingly important to achieve more stringent environmental safety standards. This study develops a lab-scale reactor for bioremediation of aqueous mercury using a biofilm producing bacterial strain, KBH10 isolated from mercury polluted soil. The strain was found resistant to 80 mg/L of HgCl2 and identified as Bacillus nealsonii via 16S rRNA gene sequence analysis. The strain KBH10 was characterized for optimum growth parameters and its mercury biotransformation potential was validated through mercuric reductase assay. A packed-bed column bioreactor was designed for biofilm-mediated mercury removal from artificially contaminated water and residual mercury was estimated. Strain KBH10 could grow at a range of temperature (20–50 °C) and pH (6.0–9.0) with optimum temperature established at 30 °C and pH 7.0. The optimum mercuric reductase activity (77.8 ± 1.7 U/mg) was reported at 30 °C and was stable at a temperature range of 20–50 °C. The residual mercury analysis of artificially contaminated water indicated 60.6 ± 1.5% reduction in mercury content within 5 h of exposure. This regenerative process of biofilm-mediated mercury removal in a packed-bed column bioreactor can provide new insight of its potential use in mercury bioremediation.

1992 ◽  
Vol 14 (6) ◽  
pp. 486-488 ◽  
Author(s):  
Ashok Pandey ◽  
S. Radhakrishnan

2003 ◽  
Vol 34 ◽  
pp. 102-104 ◽  
Author(s):  
Cristiane Vanessa Tagliari ◽  
Raquel K. Sanson ◽  
André Zanette ◽  
Telma Teixeira Franco ◽  
Carlos Ricardo Soccol

1986 ◽  
Vol 51 (6) ◽  
pp. 1222-1239 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk

Expression have been derived in the paper for all four possible transfer functions between the inlet and the outlet gas and liquid steams under the counter-current absorption of a poorly soluble gas in a packed bed column. The transfer functions have been derived for the axially dispersed model with stagnant zone in the liquid phase and the axially dispersed model for the gas phase with interfacial transport of a gaseous component (PDE - AD). calculations with practical values of parameters suggest that only two of these transfer functions are applicable for experimental data evaluation.


1982 ◽  
Vol 47 (10) ◽  
pp. 2639-2653 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk

Expressions have been derived for four possible transfer functions of a model of physical absorption of a poorly soluble gas in a packed bed column. The model has been based on axially dispersed flow of gas, plug flow of liquid through stagnant and dynamic regions and interfacial transport of the absorbed component. The obtained transfer functions have been transformed into the frequency domain and their amplitude ratios and phase lags have been evaluated using the complex arithmetic feature of the EC-1033 computer. Two of the derived transfer functions have been found directly applicable for processing of experimental data. Of the remaining two one is useable with the limitations to absorption on a shallow layer of packing, the other is entirely worthless for the case of poorly soluble gases.


1987 ◽  
Vol 52 (7) ◽  
pp. 1715-1729 ◽  
Author(s):  
Pavel Moravec ◽  
Vladimír Staněk

An experimental method and technique are described in the paper of simultaneous detection of the transfer functions outlet-gas-stream-to-inlet-gas-stream and outlet-liquid-stream-to-inlet-gas-stream for the absorption of oxygen into water in a counter-current packed bed column. Both transfer functions were simultaneously monitored by means of three oxygen electrodes operating on the polarographic principle. The signals of these electrodes were processed in three steps to yield parameters of the model of physical absorption of gas. The first step was on-line evaluation of the Fourier coefficients of the principal harmonic component in all three monitored streams. The second step was the calculation of the frequency characteristics of both transfer functions while the third step yielded parameters of the model by optimization in the frequency domain. The method permits simultaneous evaluation of the parameters of the flow of both phases in the column and the interfacial transfer of oxygen.


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