Metals-induced functional stress in sulphate-reducing thermophiles

Abstract

All toxic metals have been known to inhibit different activities of sulphate-reducing bacteria (SRB) at different concentrations. The present study delineates functional responses of two thermophilic SRB species (Desulfotomaculum reducens-HA1 and Desulfotomaculum hydrothermale-HA2) to toxic metals. Bacterial activity was assessed in terms of sulphate reduction and metal precipitation employing four concentrations (1, 5, 10 and 15 ppm) of three dissolved toxic metals (Cu, Cr and Ni) independently. Both sulphidogenic bacterial species showed results in a very narrow range of fluctuations. In general, bioprecipitation and sulphate reduction were pronounced at lower concentrations (1 and 5 ppm) and got inhibited at higher concentrations (10 and 15 ppm). The order of precipitation and sulphate reduction for the subject metals was Ni > Cr > Cu. The findings of this study will be helpful in developing economical and environmental friendly bioremediation process(es) tending to operate at extreme conditions around the concentrations in indicated suitable metals-loaded effluents.

Exploited application of sulfate-reducing bacteria for concomitant treatment of metallic and non-metallic wastes: a mini review

“…SRB make morphologically and physiologically a diverse group of obligatory anaerobes which share the ability to dissimilate sulfate to sulfide while oxidizing various growth substrates (Willis et al 1997 ). These prokaryotic microorganisms are much versatile in their metabolism as well as in the environmental conditions in which they thrive and particularly make their importance in specific ecosystems such as acid mine drainages, cyanobacterial microbial mats, deep-sea hydrothermal vents, hypersaline microbial mats, marine and freshwater sediments, methane zone of marine sediments, oil fields’ environments, polluted environments such as anaerobic purification plants, rhizosphere of plants and rice fields (Fauque 1995 ; Dhillon et al 2003 ; Rabus et al 2006 ; Foti et al 2007 ; Leloup et al 2007 ; Ollivier et al 2007 ; Muyzer and Stams 2008 ; Hussain and Qazi 2016 ; Wissuwa et al 2016 ). In the above mentioned ecosystems, SRB have to cope with drastic physicochemical conditions including high temperature and high pressure, etc.…”

“…A number of studies, based on the applications of SRB have been carried out for the treatment of simulated and real wastewaters contaminated with a range of pollutants. The latest advancement in the applications of SRB have shown that SRB are used to treat various environmental contaminants including metals (Hussain and Qazi 2016 ; Mothe et al 2016 ; Zhang et al 2016b ), metalloids (Battaglia-Brunet et al 2012 ; Altun et al 2014 ; Sahinkaya et al 2015 ) sulfates (Hussain and Qazi 2014 , 2016 ; Hussain et al 2014a ), methane (Krukenberg et al 2016 ), various non-methane hydrocarbons e.g. alkanes (Callaghan et al 2012 ; Khelifi et al 2014 ; Kleindienst et al 2014 ; Herath et al 2016 ) and alkenes (Fullerton et al 2013 ), alicyclic hydrocarbons e.g.…”

“…The escaped H 2 S my pose severe environmental impacts as well. This information necessitates optimization of sulfidogenesis and the wastes to be treated within tangibly designed bioreactors allowing maximum contact area and time for the H 2 S and waste(s) to react (Hussain and Qazi 2016 ). The H 2 S exhaust can also be controlled by making the entire remedial setup closed.…”

“…Keeping in view the above mentioned facts, metal-tolerant sulfidogenic bacteria have been perceived an appealing condition for precipitating metals from effluents in the form of their sulfides (Gadd 2000 ; Hussain and Qazi 2016 ). SRB play an important role in metal sulfide immobilization in anaerobic environments that contain high concentrations of metals (Kaksonen et al 2004 ; Van Roy et al 2006 ).…”

Dual action of chromium-reducing and nitrogen-fixing Bacillus megaterium-ASNF3 for improved agro-rehabilitation of chromium-stressed soils

“…Given that this method is expensive and can possibly create generation of secondary pollutants, its application can be problematic (Ihsanullah et al 2016 ). Owing to high efficacy and low operational cost, the bioremedial strategies have been advocated, including studies based on the utilization of genetic potential of microorganisms, originally isolated from the contaminated environment (Thacker et al 2006 ; Cetin et al 2008 ; Martins et al 2010 ; Hussain and Qazi 2016 ). The line of action has high likelihood of isolating microbial cultures which can successfully be augmented for remediating the contamination.…”