Behavior of sulfate reducing bacteria under oligotrophic conditions and oxygen stress in particle-free systems related to drinking water

Abstract

The response of sulfate reducing bacteria (SRB) to oxygen stress under oligotrophic conditions in particle-free systems was studied in (i) sterile Berlin drinking water; (ii) mineral medium; and (iii) in coculture experiments with aerobic bacteria. Using a polyphasic approach including anaerobic cultivation, fluorescent in situ hybridization (FISH) and digital image analysis, the behavior of the strains zt3l and zt10e, isolated from Berlin groundwater and affiliated to the family Desulfovibrionaceae, was compared to the type strains Desulfomicrobium baculatum and Desulfovibrio desulfuricans. Anaerobic deep agar dilution series were performed for the determination of cell culturability. FISH and subsequent digital image analysis of probe-conferred fluorescence intensities were used for the assessment of metabolic activity. For the in situ identification of both isolates in coculture tests, two strain-specific oligonucleotides were developed and evaluated. The total cell counts of stressed SRB in drinking water decreased during the course of the assay dependent on the strain. Both environmental isolates could be cultured for a longer period than cells of D. baculatum and D. desulfuricans, respectively. The FISH intensities showed a strain-specific behavior. When exposed to simultaneous oxygen stress and carbon limitation in mineral medium, total cell counts of all four strains remained constant throughout a period of 72 days. The rate of culturability differed between the investigated strains. The decrease of metabolic activity as assessed by FISH was a strain-specific property. Exposure of SRB to oxygen stress and carbon starvation in coculture experiments with Aquabacterium commune resulted in strain dependent prolonged culturability and a delayed decrease of the metabolic activity compared to pure culture tests for all strains tested. Total cell counts of SRB were constant throughout the whole experiment.

Bacterial community analysis of shallow groundwater undergoing sequential anaerobic and aerobic chloroethene biotransformation

“…Well B3 contained sequences similar to a manganese oxidizing bacterium, Leptothrix discophora strain SP‐6 (115‐18, E=1e‐133, 93%), a denitrifying pivalic acid degrading bacterium (115‐39, E=0, 97%), hydrogen oxidizing bacteria (112‐53, E=0, 99%) and a type II methane oxidizing bacterium (115‐14, E=0, 98%) (Siering & Ghiorse, 1996; Wen et al , 1999; Heyer et al , 2002; Probian et al , 2003). Both wells T2 and T5 contained many sequences related to uncultured and/or uncharacterized bacteria or cloned sequences; however, well T2 contained 16S rRNA gene sequences similar to that of the filamentous bacterium Haliscomenobacter hydrosis (110‐14, E=0, 98%), normally associated with wastewater treatment systems, as well as 16S rRNA gene sequences related to a hydrogen oxidizing bacterium (115‐72, E=0, 99%) and a sulfate reducing bacterium (115‐76, E=0, 99%) (Wen et al , 1999; Bade et al , 2000; Schauer & Hahn, 2005).…”

The ‘strict’ anaerobe Desulfovibrio gigas contains a membrane‐bound oxygen‐reducing respiratory chain

“…In particular, sulfate‐reducers were isolated from oxic environments close to anoxic or periodically anoxic zones (e.g. [4–6]). Also, these bacteria were shown to produce ATP in the presence of oxygen (e.g.…”

Anaerobic microorganisms in astrobiological analogue environments: from field site to culture collection

“…Khelaifia et al 2013), iron-reducers (e. g. Hori et al 2015) and sulphate-reducers (e.g. Bade et al 2000) in addition to the ones we used. As the culturable population of any community is generally small (Stewart 2012), there exists a trade-off between the restrictions imposed by the experimental requirements and the maximization of the isolated microbial diversity.…”