Combination of zero-valent iron and anaerobic microorganisms immobilized in luffa sponge for degrading 1,1,1-trichloroethane and the relevant microbial community analysis

Abstract

1,1,1-Trichloroethane (1,1,1-TCA), a dense non-aqueous phase liquid (DNAPL), is relatively slow to remediate naturally; combination of zero-valent iron and immobilized microorganism is a potential means to accelerate DNAPL biodegradation. We first adopted high density luffa sponge (HDLS) as immobilized microorganism carrier. The experimental results demonstrated that (1) the supernatant liquid microorganisms were the optimal immobilized microorganisms for HDLS and (2) the combination of zero-valent iron and immobilized microorganisms accelerated 1,1,1-TCA transformation. Furthermore, in the long-term remediation process, anaerobic microorganisms produced reductant HS which was beneficial to zero-valent iron PRBs. Through further study of the microbial community, we found that majority of the sulfate-reducing bacteria (SRB) perfectly adapted to the process of 1,1,1-TCA co-metabolism dechlorination. Desulfobulbus and Desulfococcus potentially were the special SRB that contributed significantly to TCA co-metabolism. Additionally, 1,1,1-TCA induced the generation of new SRB and stimulated the growth of majority of dominating methanogens. The results indicated that they played a constructive role in accelerating the dechlorination of 1,1,1-TCA, reduction of sulfate, and improving the production of CH. Consequently, combination of zero-valent iron and immobilized microorganisms for remediating groundwater by contaminated 1,1,1-TCA is a sustainable and green remediation technology. Especially for groundwater of SO type contaminated by 1,1,1-TCA, in the long-term course of combination degradation, cyclic utilization of HS to prolong the service life of zero-valent iron PRBs. H and CH generated to capture as potential energy resource. Based on this, a tentative reaction mechanism for Fe biodegradation of 1,1,1-TCA was proposed.

Comparison of bacterial communities associated withXestospongia testudinaria, sediment and seawater in a Singaporean coral reef ecosystem

“…Members of this family are strictly anaerobic sulphate-reducing bacteria, mainly found in freshwater, sewage sludge and marine habitats (Kuever, 2014). However, they have also previously been detected in sponges (Fiore et al , 2013; Cleary et al , 2015; Wang & Wu, 2017).…”

Adsorption-Degradation of Polycyclic Aromatic Hydrocarbons in Soil by Immobilized Mixed Bacteria and Its Effect on Microbial Communities

“…The ability of immobilized microorganisms to degrade PAHs was superior to that of free bacteria. , Loofah is a cell-immobilized carrier with high potential due to its cross-sectional lattice framework and high porosity. , Meanwhile, as a carrier, loofah has a strong adsorption capacity for microorganisms and PAH-degrading enzymes. High porosity can ensure the adsorption and fixation of a large number of microorganisms, and thus provides a good living environment for the bacteria and avoids direct contact between the bacteria and the harsh soil environment. − …”

Soil Microorganisms and Their Potential in Pesticide Biodegradation; A Review Article

“…Immobilized cells are unaffected by distresses in the environment and are less disposed to poisonous materials, which makes immobilized cell attractive for remediation of organic compounds such as pesticides (Engler and Wild, 2009). The biological approaches for the treatments of pollutants have attracted increase attention to be a promising alternative for the removal of pesticides and other pollutants present in the environment (Es et al, 2016;Wang and Wu, 2017). Recently, the entrapment of the cells in gellan gum, calcium alginate, polyacrylonitrilehas agarose, polyamide, polyvinyl alcohol, polyurethane as well as polypropylene were recommended as promising method for microbial degradation of contaminants (Paisio et al, 2016;Talwar and Ninnekar, 2015).…”