Journal
ENVIRONMENTAL MICROBIOLOGY REPORTS
Volume 15, Issue 4, Pages 324-334Publisher
WILEY
DOI: 10.1111/1758-2229.13149
Keywords
-
Categories
Ask authors/readers for more resources
In this study, a chemostat was used to investigate the autotrophic nitrate-reducing Fe(II)-oxidizing culture KS over 24 days. The results showed that the Fe(II) oxidation rate was highest in the chemostat, but the extent of oxidation was similar to the other experimental setups. Short-range ordered Fe(III) phases and goethite were detected in the chemostat. The study revealed the importance of reactive nitrogen intermediates on Fe(II) oxidation, mineral formation, and cell-mineral interactions under continuous conditions.
Laboratory-based studies on microbial Fe(II) oxidation are commonly performed for 5-10 days in small volumes with high substrate concentrations, resulting in geochemical gradients and volumetric effects caused by sampling. We used a chemostat to enable uninterrupted supply of medium and investigated autotrophic nitrate-reducing Fe(II)-oxidizing culture KS for 24 days. We analysed Fe- and N-speciation, cell-mineral associations, and the identity of minerals. Results were compared to batch systems (50 and 700 mL-static/shaken). The Fe(II) oxidation rate was highest in the chemostat with 7.57 mM Fe(II) d(-1), while the extent of oxidation was similar to the other experimental setups (average oxidation of 92% of all Fe(II)). Short-range ordered Fe(III) phases, presumably ferrihydrite, precipitated and later goethite was detected in the chemostat. The 1 mM solid phase Fe(II) remained in the chemostat, up to 15 mu M of reactive nitrite was measured, and 42% of visualized cells were partially or completely mineral-encrusted, likely caused by abiotic oxidation of Fe(II) by nitrite. Despite (partial) encrustation, cells were still viable. Our results show that even with similar oxidation rates as in batch cultures, cultivating Fe(II)-oxidizing microorganisms under continuous conditions reveals the importance of reactive nitrogen intermediates on Fe(II) oxidation, mineral formation and cell-mineral interactions.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available