Acetate limitation selects Geobacter from mixed inoculum and reduces polysaccharide in electroactive biofilm

Li, Tian; Zhou, Qixing; Zhou, Lean; Yan, Yuqing; Liao, Chengmei; Wan, Lili; An, Jingkun; Li, Nan; Wang, Xin

doi:10.1016/j.watres.2020.115776

Cited by 77 publications

(37 citation statements)

References 51 publications

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“…In order to provide carbon-limiting conditions, an excess of electron acceptor (30 mM nitrate) was applied and other microorganisms were allowed to colonize columns. G. metallireducens is known to be a good competitor in microbial communities under acetate limitation (Li et al, 2020) and we expected similar scenario for benzoate limitation. The results were compared to our previously conducted studies where G. metallireducens was cultivated in batch and retentostats in the presence of excessive electron acceptor [50 mM Fe(III)citrate] (Marozava et al, 2014a,b).…”

Section: Introductionsupporting

confidence: 66%

Adaptation of Carbon Source Utilization Patterns of Geobacter metallireducens During Sessile Growth

2020

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Section: Introductionsupporting

confidence: 66%

Adaptation of Carbon Source Utilization Patterns of Geobacter metallireducens During Sessile Growth

2020

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“…Here, the identification of a single redox system was not possible due to the increased peak width and shift to higher potentials, maybe caused by the increased presence of redox active molecules that are not necessarily involved in extracellular electron transfer. This likely increase in redox active molecules can be the result of a higher amount of extracellular polymeric substances that are more abundant in old biofilms compared to young biofilms …”

Section: Resultsmentioning

confidence: 99%

“…A reason for the observed behavior could be that complex microbial communities can be formed. − In this complex microbial community, for instance, fermentative bacteria and non-planktonic methanogens dominate the outer layers of the biofilm electrode, which means that in older biofilms they are more prominent, thus possibly protecting the electroactive bacteria located in the inner layers to a certain extent from potential inhibitors or alternative electron acceptors present in the AD effluent . Another reason could be the higher abundance of extracellular polymeric substances in old biofilms that protect the bacteria from unfavorable environmental conditions …”

Section: Resultsmentioning

confidence: 99%

Benefits of Age–Improved Resistance of Mature Electroactive Biofilm Anodes in Anaerobic Digestion

Ngoumelah

Kretzschmar

2021

Environ. Sci. Technol.

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Anaerobic digestion (AD) and microbial electrochemical technologies (MET) can be combined in manifold ways. Recent studies show negative influences of AD effluents on the performance of pre-grown Geobacter spp.-dominated biofilm anodes. In this study, it was investigated how such biofilm anodes are affected by AD effluents. Therefore, experiments using AD effluents in different concentrations (0−100%) in combination with biofilms of different ages were performed. Furthermore, the activity of methanogens was inhibited and minimized by application of 2-bromoethanesulfonate (2-BES) and microfiltration, respectively. Biofilms pre-grown for 5 weeks show higher resistance against AD effluents compared to biofilms pre-grown for only 3 weeks. Nevertheless, adaptation of biofilms to AD effluents was not successful. Biofilm activity in terms of coulombic efficiency and maximum current density (j max ) dropped by factor 32.2 ± 3.2 and 38.9 ± 8.4, respectively. The application of 2-BES and microfiltration had positive effects on the biofilm activity. The results support the assumption that methanogens or further compounds not studied here, for example, protozoans, which may have been inhibited or removed by 2-BES application or microfiltration, have an immediate influence on the stability of Geobacter spp.-dominated biofilms and may limit their practical application in AD environments.

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“…Further, low acetate concentrations are shown to impose a selective pressure to enrich for Geobacter sp. 6 , 19 . The above features provide a selective advantage for the growth of G. sulfurreducens on the anode over more flexible and metabolically versatile EAB such as Shewanella oneidensis (another model EAB), and it also gives them a competitive advantage over non-EAB such as acetoclastic methanogens.…”

Section: Introductionmentioning

confidence: 99%

Competition of two highly specialized and efficient acetoclastic electroactive bacteria for acetate in biofilm anode of microbial electrolysis cell

Sapireddy

Katuri

Ali

et al. 2021

npj Biofilms Microbiomes

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Maintaining functional stability of microbial electrolysis cell (MEC) treating wastewater depends on maintaining functional redundancy of efficient electroactive bacteria (EAB) on the anode biofilm. Therefore, investigating whether efficient EAB competing for the same resources (electron donor and acceptor) co-exist at the anode biofilm is key for the successful application of MEC for wastewater treatment. Here, we compare the electrochemical and kinetic properties of two efficient acetoclastic EAB, Geobacter sulfurreducens (GS) and Desulfuromonas acetexigens (DA), grown as monoculture in MECs fed with acetate. Additionally, we monitor the evolution of DA and GS in co-culture MECs fed with acetate or domestic wastewater using fluorescent in situ hybridization. The apparent Monod kinetic parameters reveal that DA possesses higher jmax (10.7 ± 0.4 A/m2) and lower KS, app (2 ± 0.15 mM) compared to GS biofilms (jmax: 9.6 ± 0.2 A/m2 and KS, app: 2.9 ± 0.2 mM). Further, more donor electrons are diverted to the anode for respiration in DA compared to GS. In acetate-fed co-culture MECs, DA (98% abundance) outcompete GS for anode-dependent growth. In contrast, both EAB co-exist (DA: 55 ± 2%; GS: 24 ± 1.1%) in wastewater-fed co-culture MECs despite the advantage of DA over GS based on kinetic parameters alone. The co-existence of efficient acetoclastic EAB with high current density in MECs fed with wastewater is significant in the context of functional redundancy to maintain stable performance. Our findings also provide insight to future studies on bioaugmentation of wastewater-fed MECs with efficient EAB to enhance performance.

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Acetate limitation selects Geobacter from mixed inoculum and reduces polysaccharide in electroactive biofilm

Cited by 77 publications

References 51 publications

Adaptation of Carbon Source Utilization Patterns of Geobacter metallireducens During Sessile Growth

Adaptation of Carbon Source Utilization Patterns of Geobacter metallireducens During Sessile Growth

Benefits of Age–Improved Resistance of Mature Electroactive Biofilm Anodes in Anaerobic Digestion

Competition of two highly specialized and efficient acetoclastic electroactive bacteria for acetate in biofilm anode of microbial electrolysis cell

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