Metal biouptake by actively growing cells of metal-tolerant bacterial strains

Abstract

Metal uptake potentials of Pseudomonas aeruginosa CA207Ni, Burkholderia cepacia CA96Co, Rhodococcus sp. AL03Ni, and Corynebacterium kutscheri FL108Hg were studied to determine their competence in detoxification of toxic metals during growth. Metabolism-dependent metal biouptake of the bacteria revealed appreciable uptake of the metals (57-61, 10-30, 23-60, and 10-16 mg g dw(-1) of Ni(2+), Cr(6+), Co(2+), and Cd(2+), respectively) from medium, after initial drop in pH, without lag phase. The bacteria exhibited 95-100% removal efficiency for the metals from aqueous medium as 21 (±0.8)-84 (±2.0) concentration factors of the metals were transported into the bacterial systems. Passive adsorption onto the cell surfaces occurred within 2-h contact, and afterwards, there was continuous accumulation for 12 days. Biosorption data of the bacteria were only fitted into Langmuir isotherm model when strains AL96Co, CA207Ni, and AL03Ni interacted with Ni(2+), achieving maximum uptake of 9.87, 2.72, and 2.69 mg g dw(-1), respectively. This study established that the actively growing bacterial strains displayed, at least, 97.0% (±1.5) continuous active removals of metals upon adsorption. The bacteria would be good candidates for designing bioreactor useful in the detoxification campaign of heavy metal-polluted systems.

Mercury removal during growth of mercury tolerant and self-aggregating Yarrowia spp.

“…( Idd1 and Idd2 ), previously isolated and deposited to Japan Collection of Microorganisms under Accession no. JCM 30162 (strain Idd1 ), and JCM 30163 (strain Idd2 ) (stored at −80 °C in 1:1 glycerol:YM broth) (Oyetibo et al 2015a ) were resuscitated by inoculating onto sterile Bacto YM broth (Becton, Dickinson and Co, Sparks, MD, USA). After 72 h incubation (30 °C, 150 rpm), 100 µl culture was spread on dried surface of sterile Bacto YM broth solidified with 1.5 % agar (Wako, Osaka, Japan).…”

“…Notable microbial adaptations to toxic metal perturbation that have been variously harnessed in environmental biotechnology of heavy metal mitigation include exclusion of toxic metals via influx and efflux pumping (Nies 2007 ); partition of toxic metals through adsorption (Oyetibo et al 2015a ), internalization (Strouhal et al 2003 ), or sequestration (Huang et al 1999 ); and demobilization upon binding with organic ligands like exopolymers secreted by organisms (Guibaud et al 2009 ). Microbial techniques currently used in mercury bioremediation include reduction of Hg 2+ to volatile elemental mercury (Hg 0 ) (Huang et al 1999 ), and cellular adsorption of mercuric ions using dead and/or live microbial cells (Francois et al 2012 ; Oyetibo et al 2014 , 2015a , b ). Extracellular polymeric substances (EPS) produced by microbial cells during growth play a crucial role in immobilizing heavy metals (Comte et al 2008 ; Francois et al 2012 ) and consequently protect cells from deleterious effects of toxic metals.…”

Isolation of cadmium-resistance and siderophore-producing endophytic bacteria and their potential use for soil cadmium remediation

“…Also, their cell wall possesses unique major components of lipopolysaccharide and lipoprotein that bind the metal onto the cell envelope [ 43 , 49 , 50 ]. Most strains showed decreasing removal rates within continuously elevated Cd 2+ concentration of 10–100 mg L −1 , which may be due to the fact that continuously elevated Cd toxicity reduced the biomass of the strain, and decreased the binding sites and surface area available for Cd 2+ [ 51 ]. However, the Cd 2+ removal by strain JLS17 did not decrease significantly as most strains did, and interestingly, higher concentration seemed to promote the Cd 2+ removal.…”

Estudo do potencial de biossorção de cobre por <i>Rhodococcus erythropolis</i> e <i>Enterobacter cloacae</i> isoladas de uma área de mineração.

“…As águas residuais são um problema há muitos anos, sendo seus tratamentos limitados a relação custo-eficácia dos processos físico-químicos mais comuns, como oxidação e redução, precipitação química, filtração, tratamento eletroquímico, evaporação, troca iónica e osmose reversa (El Baz et al., 2015;Khan, Husain, & Hejazi, 2004;Oyetibo et al., 2015;Vijayaraghavan, Palanivelu, & Velan, 2006 (Malik, 2004;Wang & Chen, 2009). Outros autores como Gavrilescu, 2004;Lemos, Carlos, & Farias, 2008;B.…”

“…As atividades que o homem exerce atualmente acrescentam ao meio ambiente, através de despejos não controlados, quantidades de metais que se somam às resultantes do intemperismo natural de rochas. Esta crescente contaminação foi ignorada até o trágico evento de Minamata em 1956, no Japão, onde centenas de pessoas morreram envenenadas com metil-mercúrio e dezenas de mulheres tiveram seus fetos não desenvolvidos adequadamente devido ao descarte inadequado do efluente industrial da fabricação de acetaldeído (Fu & Wang, 2011;Harada, 1995;Oyetibo, Ilori, Obayori, & Amund, 2015). O metal se acumulou nos peixes da região e consequentemente chegou à população.…”