Akademik Veri Yönetim Sistemi
EUROCORR2022, Berlin, Almanya, 28 Ağustos - 01 Eylül 2022, ss.1
Microorganisms contaminating aircraft fuels may attach to the metallic surfaces of the
aircraft skeleton and form a biofilm layer that damages fuel tanks causing high
maintenance/repair costs and serious safety problems. Many aircraft accidents that
result in fire or explosions due to fuel leaking from damaged tanks are reported to be
microbiologically induced corrosion (MIC)-related.
In recent years, manganese oxidizing bacteria (MOB) have attracted attention due to
their responsibility for MIC. MOB in the biofilm cause the biomineralization of Mn+2, free
in water, with the help of oxygen to MnO2. The presence of Mn-oxides increases the
cathodic reactions in the metal causing corrosion and may also form differential
aeration cells, promoting the proliferation of anaerobes responsible for MIC. In this
context, the presence of MOB and Mn oxides may be important reasons for the MIC in
aircraft fuel tanks that have not been sufficiently investigated yet.
The first aim of this study was to isolate MOB in the aircraft fuel samples. The second
aim was to investigate growth curves and Mn-oxide production abilities of the selected
ones using a modified-Mn broth. The third aim was to determine growth curve and
Mn-oxide production ability of the most active MOB isolate using the modified Mn broth
with different Mn concentrations (0.5, 1, 2 and 3 g/L).
In this respect, aerobic heterotrophic bacteria were isolated from the fuel samples
taken from different passenger aircrafts and then MOB were determined by LBB test.
Among MOB, three were selected, molecularly identified, and growth curves and Mn
oxidation abilities were evaluated using the modified-Mn Broth. Then a second set up
was prepared by the modified-Mn Broth prepared with different Mn concentrations (0.5,
1, 2 and 3 g/L) to evaluate growth curve and Mn oxidation abilitiy of the most active
MOB isolate among the three selected.
According to the 16S rDNA sequence analysis, MOB isolates were identified as
Burkholderia sp. (98.80%), Sphingomonas sp. (98.75%) and Micromonospora sp.
(97.94%). All isolates were able to grow in the modified-Mn Broth showing different
growth characteristics. Burkholderia sp. and Micromonospora sp. did not oxidize Mn.
Sphingomonas sp. was determined as the most active MOB, showing better growth
both at 1 g/L and 2 g/L Mn concentrations. Considering the Mn oxidation ability, 1 g/L
Mn concentration of modified-Mn Broth was the best for Sphingomonas sp.. The
obtained results suggest that the medium to be used for the corrosion experiments
carried by MOB should be selected specifically according to the bacterial species.