Isolation and Bioaugmentation of an Estradiol-Degrading Bacterium and Its Integration into a Mature Biofilm

Abstract

Bioaugmentation can alter the potential activity as well as the composition of the naturally occurring microbial biota during bioremediation of a contaminated site. The focus of the current study is the pollutant 17␤-estradiol (E2), which can cause endocrine effects and is potentially harmful to aquatic biota and to public health. The community composition and function of biofilms, originating from a wetland system, as affected by augmentation of an estradiol-degrading bacterium (EDB-LI1) under different conditions, were investigated. EDB-LI1 inoculation into biofilm from two wetland ponds representing early and advanced water treatment stages, respectively, yielded three significant observations, as follows: (i) EDB-LI1, enriched from a biofilm of a constructed wetland wastewater treatment system, was detected (by quantitative PCR [qPCR] analysis) in this environment in the augmented biofilm only; (ii) the augmented biofilm acquired the ability to remove estradiol; and (iii) the bacterial community composition (analyzed by PCR-denaturing gradient gel electrophoresis [DGGE]) of the augmented biofilm differed from that of the control biofilm. Furthermore, EDB-LI1 bioaugmentation showed a higher level of removal of estradiol with biofilms that originated from the advancedtreatment-stage wetland pond than those from the early-treatment-stage pond. Hence, the bioaugmentation efficiency of EDB-LI1 depends on both the quality of the feed water and the microbial community composition in the pond.

Enhancement in copper extraction from chalcopyrite by re-inoculation of different acidophilic, moderately thermophilic microorganisms

“…In all re-inoculation tests, the most significant enhancements in copper extractions were observed for 'Lf-1/1', 'Lf-1/3' and in a less extent 'Ac-1/1' systems. Advantages by microbial re-inoculation at the early stage could be summarized by the following principles (El Fantroussi and Agathos, 2005;Iasur-Kruh et al, 2011): (1) In contrast to re-inoculation at the middle stage (Fig. 7), a higher level of the re-inoculated strain survived and/or grew in the bioleaching environment after re-inoculation at the early stage (Fig.…”

“…The operation of re-inoculation is to re-add pre-grown specific indigenous or allochthonous wild type cultures into a bio-treatment system to improve the catabolism of specific compounds, e.g. diesel oil in the contaminated soil, 17β-estradiol in wastewater, or some pharmaceuticals from sewage sludge (Bento et al, 2005;Iasur-Kruh et al, 2011;Rodríguez-Rodríguez et al, 2014). Some previous studies have indicated that the re-inoculation of biomass enhanced the removal of toxic or recalcitrant compounds as well as changed the composition of the naturally occurring microbial biota in a system (Iasur-Kruh et al, 2011;Wen et al, 2013).…”

Invasibility of resident biofilms by allochthonous communities in bioreactors

“…The cooperative interaction between the residents of the mixed biofilm provided a protection against the invasion by P. tunicata, as well as the diffusion of antimicrobial agents (Burmølle et al, 2006). In wetland ponds, the amount of nutrients supplied determined the effectiveness of invasion by promoting coexistence of species, including an introduced allochthonous estradiol-degrading bacterium which increased the removal of estradiol from the systems (Iasur-Kruh et al, 2011). Yet, perturbations (i.e.…”

“…The ability of an invader to adhere and clolonise the native communities has a pivotal role (Russo et al, 2015), but the true drivers of the success of invasion seem to be related to the characteristics of the resident community, such as diversity and evenness, competition for resources, as well as changes in environmental conditions (van Elsas et al, 2012;Iasur-Kruh et al, 2011;Burmølle et al, 2006;Guillier et al, 2008;Mejlholm and Dalgaard, 2007;Zhao et al, 2006). A negative correlation between soil microbial diversity and the survival of Escherichia coli O157:H7 was reported by van Elsas et al (2012).…”

“…Several studies attempted to understand the mechanisms driving the invasion of biofilms by allochthonous organisms (Burmølle et al, 2006;Iasur-Kruh et al, 2011;Jackson et al, 2001;Zhao et al, 2006), but the conclusions are inconsistent. The ability of an invader to adhere and clolonise the native communities has a pivotal role (Russo et al, 2015), but the true drivers of the success of invasion seem to be related to the characteristics of the resident community, such as diversity and evenness, competition for resources, as well as changes in environmental conditions (van Elsas et al, 2012;Iasur-Kruh et al, 2011;Burmølle et al, 2006;Guillier et al, 2008;Mejlholm and Dalgaard, 2007;Zhao et al, 2006).…”