Australian Centre for Water
and Environmental Biotechnology

AWMC Seminar Program: Investigating microbial sulfur and nitrogen and carbon metabolism and extracellular electron transfer in extremophiles

By Dr Gaofeng Ni

In an acidophilic MFCs study for tetrathionate (S4O62-) degradation, a combined metagenomic & metatranscriptomic approach revealed the presence of Ferroplasma, Acidithiobacillus, Sulfobacillus, and Cuniculiplasma. This microbial community was suggested to metabolize inorganic sulfur compounds via multiple pathways, and transfer the electrons released from oxidation to the electrode via soluble electron shuttles. The Ferroplasma-like population in this study was the most active1. Furthermore, this microbiome could adapt to the acidic environment utilizing strategies such as accumulation of intracellular K+; consumption and extrusion of H+; as well as reducing cell permeability1. Metatranscriptomic investigation of a psychrophilic MFC study for thiocyanate (SCN-) degradation suggested that Thiobacillus was the predominant and most active population. mRNA analysis revealed that thiocyanate was metabolized primarily via the ‘cyanate’ degradation pathway; and the resultant sulfide was oxidized with electrons being transferred via the secretion of electron shuttles2. Transcripts for ammonium oxidation are absent, ammonium was suggested to be assimilated. Finally, it was identified that these microorganisms utilized cold-shock proteins, molecular chaperones, compatible solutes and so on to combat low temperatures (8 °C)2.

The newly discovered “Feammox” process that integrates anaerobic ammonium oxidation and iron reduction is significant for nitrogen and iron cycle, and also relevant for nitrogen removal from wastewaters3. We plan to sample from ammonium and iron rich environments and carry out enrichment culturing. This will be followed by molecular microbiological analysis. Meanwhile, I will also be collaborating at AWMC using these techniques to investigate microbial nitrogen, carbon, and iron metabolism and so on.

1 Ni et al., A Novel Inorganic Sulfur Compound Metabolizing Ferroplasma-like Population is Suggested to Mediate Extracellular Electron Transfer. Frontiers in Microbiology (2018).

2 Ni, et al., Microbial Community and Metabolic Activity in Thiocyanate Degrading Low Temperature Microbial Fuel Cells. Frontiers in Microbiology (2018).

3 Yang et al., Nitrogen loss from soil through anaerobic ammonium oxidation coupled to iron reduction. Nature Geoscience (2012).




AWMC hosts a free seminar every Friday from 9am.

Event Details
Date & Time: 
Friday, 03 May 2019
9am - 10am
Venue: AIBN Building 75, Level 1 Seminar Room

Event Contact: