The Role of Enriched Microbial Consortium on Iron-Reducing Bioaugmentation in Sediments

Abstract

Microbial iron reduction is an important biogeochemical process and involved in various engineered processes, including the traditional clay dyeing processes. Bioaugmentation with iron reducing bacteria (IRB) is generally considered as an effective method to enhance the activity of iron reduction. However, limited information is available about the role of IRB on bioaugmentation. To reveal the roles of introduced IRB on bioaugmentation, an IRB consortium enriched with ferric citrate was inoculated into three Fe(II)-poor sediments which served as the pigments for Gambiered Guangdong silk dyeing. After bioaugmentation, the dyeabilities of all sediments met the demands of Gambiered Guangdong silk through increasing the concentration of key agent [precipitated Fe(II)] by 35, 27, and 61%, respectively. The microbial community analysis revealed that it was the minor species but not the dominant ones in the IRB consortium that promoted the activity of iron reduction. Meanwhile, some indigenous bacteria with the potential of iron reduction, such as Clostridium, Anaeromyxobacter, Bacillus, Pseudomonas, Geothrix, and Acinetobacter, were also stimulated to form mutualistic interaction with introduced consortium. Interestingly, the same initial IRB consortium led to the different community successions among the three sediments and there was even no common genus increasing or decreasing synchronously among the potential IRB of all bioaugmented sediments. The Mantel and canonical correspondence analysis showed that different physiochemical properties of sediments influenced the microbial community structures. This study not only provides a novel bioremediation method for obtaining usable sediments for dyeing Gambiered Guangdong silk, but also contributes to understanding the microbial response to IRB bioaugmentation.

Low-Abundance Members of the Firmicutes Facilitate Bioremediation of Soil Impacted by Highly Acidic Mine Drainage From the Malanjkhand Copper Project, India

“…Nearly complete reduction of SO 4 2− (15 mM) and Fe 3+ (5 mM) were noticed following 10–14 days of incubation, confirming their abilities for reduction of these terminal electron acceptors. The formation of black precipitates of iron sulfide in SRM and change in color of the IRM from yellow to light green or colorless with precipitation of Fe (Ferric citrate as redox indicator) (Pan et al, 2017) was also noted (Supplementary Figure S2). In order to confirm the presence of these SRB and IRB after 4 months of incubation where a decline in soluble iron concentration (Fe 2+ ) was observed due to precipitation with sulfide produced by sulfate reducing activity in the treatments, DGGE based microbial community analysis was performed with 5 months incubated microcosms (H_5M, C_5M, and C+L_5M).…”

“…Microbial taxa enriched during this study were reported to be of facultative- or strict-anaerobic nature, involved in anaerobic hydrolytic fermentation, cysteine utilization, acetate- and H 2 S-production and metal reduction (Petrie et al, 2003; Church et al, 2007; Finke and Jørgensen, 2008; Kosaka et al, 2008; Li et al, 2011; Bertel et al, 2012; AlAbbas et al, 2013; Hausmann et al, 2016; Peng et al, 2016; Pan et al, 2017). The major genera identified in this study such as Clostridium , Clostridium sensu stricto members, Lutispora , Sporobacter , Acetanaerobacterium , Caldicoprobacter , Gracilibacter , Oxobacter, Fonticella, Papillibacter , as well as unclassified members of Ruminococcaceae , Lachnospiraceae , and Christensenellaceae were all reported as anaerobic, fermentative, cellulose- and cysteine-metabolizing, acetogenic, and iron reducing members (Grech-Mora et al, 1996; Defnoun et al, 2000; Chen and Dong, 2004; Lee et al, 2006; Shiratori et al, 2008; Bouanane-Darenfed et al, 2011; Chen M. et al, 2013; Fraj et al, 2013; Peng et al, 2016).…”

“…All these members of the phylum Firmicutes were well known for their facultative to strict anaerobic metabolism , but not so much for sulfate- and iron-reduction except few taxa such as Clostridium , Desulfosporosinus , Desulfotomaculum etc. (Chockalingam and Subramanian, 2006; Church et al, 2007; Sánchez-Andrea et al, 2012b; Pan et al, 2017). The increased abundance of gene encoding dissimilatory sulfite reductase ( dsr B) and Firmicutes specific 16S rRNA gene detected in qPCR, reduction of -sulfate/-iron and rise in pH were all in strong agreement.…”

A Novel “Microbial Bait” Technique for Capturing Fe(III)-Reducing Bacteria

“…); and Chloroflexi; Nitrospirae (such as Nitrospira); Bacteriodetes; Spirochaetes; Verrucomicrobia; Sphingobacteria (Lovley et al, 1998;Coates et al, 1999;Wilkins et al, 2007;Esther et al, 2015;Hori et al, 2015;Pan et al, 2017) while Fe(III)-reducing archaea include Euryarchaeota (e.g., Methanobacterium sp.) and Crenarchaeota (Pan et al, 2017). The concentration and type of organic matter available was found to control the communities of Fe(III)reducers (Lentini et al, 2012).…”

Corrosion of Q235 Carbon Steel in Seawater Containing Mariprofundus ferrooxydans and Thalassospira sp.

“…Among the corrosive microbes, iron reducing bacteria (IRB) and oxidizing bacteria (IOB) are two kinds of special microorganisms using iron as an electron acceptor and donor, respectively, (Byrne et al, 2015). IRB combine reduction of Fe(III) with oxidation of organic matter or H 2 for energy conservation, i.e., IRB readily use dissolved Fe(III) complexes or short-range-ordered minerals (e.g., ferrihydrite) and even magnetite as terminal electron acceptors (Pan et al, 2017; Fortney et al, 2018). IOB grow with Fe(II) or H 2 as the electron donor coupled to the reduction of oxygen in environments at acidic and circumneutral pH values (Weber et al, 2006; McBeth and Emerson, 2016).…”