Identifying mystery Bacteria / Micro-organism - (Feb/05/2014 )
Hello,
I'm trying to identify a mystery bug which is growing in a process tank, creating a black "gunge". The conditions that it is growing in contain weak sulphuric acid (about 8 gram per litre) phosphoric acid plus low concentrations of hydrochloric acid, acetic acid and caustic soda.
An energy dispersive X-Ray analysis has identified Carbon, Oxygen, Sulphur, Calcium and Potassium in the material and the SEM's attached suggest it is biological material. We are still working on this and hope to put it through a bio-typer, but I was wondering if anyone recognises the micro-organism from the scan pictures?
It seems to be filamentous with nodules, which may or may not have "collapsed" during the analysis. If anyone has any ideas, let me know.
Kind regards, Alex
perhaps Thiobacillus and related species
Which part of the tank? Top, bottom? Is it an aerated or stirred tank? If you say is black... is it an steel or metal tank? If so, probably is a sulfate-reducing bacteria (SRB) can cause corrosion problems. It would be generating H2S that would react with iron derived from steel and making a black precipitate of iron sulfide. But it could easily be a fungus, base on simple calculations 8 g/L sulfuric is nearly pH=1, SRB are not that easily found in acidic conditions and even less in so extreme ones. However, I'm working with fungi isolated from mine waters and under extreme conditions most fungi tend to produce melanins (thus, black colour). So, it is likely that a fungus wuld be the base of the biofilm. The most rounded cells could easily be vesicular structures or the formation of conidia, hard to say.
Based on pictures, description and if the liquid didn't start to show orangish colour, I would discard any iron oxidising bacteria suc Acidithiobacillus or Leptospirillum as main organisms. Even more knowing how they dislike organic carbon sources and chloride ions.
By the way, the cells are all collapsed. I had similar problems with some fungi and looked nearly the same. The collapse makes difficult to make any proper guess and images are quite blurry
Hi Guys,
thanks for the help! I'll get some photo's of the sample and upload them later today. We suspect it may be an SRB , it's fermenting vigourously inside the sample bottle at the moment. The bottle is enroute from another lab, but when it arrives I'll get back with some extra information. Many thanks, Alex
I have some further information on the conditions this micro-organism is thriving in. The growth occurs mainly in the circulation pipework but forms a tide mark in the storage tank. The tank and circulation pipework is made out of polypropylene. Most of the liquor is held in a storage tank containing about 200 litres from which it is pumped up to the main process tank via PVC spray bars with polypropylene nozzles. After contacting the aluminium web, the liquor drains down back to the storage tank.
The system is not deliberately aerated, but this will occur during a spraying part of the process. I agree with you that the pH should be theoretically below 1, however this has been measured at 1.5. There are some stainless steel spray bars, but no evidence of any corrosion. I've since learnt that previously investigations into SRB causing the issue have come back negative, however we are awaiting results of our tests to confirm this.
I've attached an image and the solution does display a darker brown appearance rather than black (sorry for the poor image).
Well, if pH is 1.5 SRB are unlikely, it is known that are some in sediments of acidic environments but the microhabitat they thrive have much higher pH than the free flowing waters. The PP construction will avoid any formation of black sulfides too, so I'll discard any SRB plus considering that you would smell H2S.
By now I'll keep in mind the fungi, they are know to give problems in mining hydrometallurgical exploitations using low pH leachants and there are even reports of they growing in other industrial acid conductions with just 0.1 N HCl. And the brownish colour can still be indicative of melanins.
If you can get an optical microscope images would be easy to determine the origin of the bulk biomass present.
Could you explain how you calculated the pH ? How come 8g/L sulfuric acid is pH 1 ? How did you calculate this?
El Crazy Xabi on Thu Feb 6 03:22:53 2014 said:
Which part of the tank? Top, bottom? Is it an aerated or stirred tank? If you say is black... is it an steel or metal tank? If so, probably is a sulfate-reducing bacteria (SRB) can cause corrosion problems. It would be generating H2S that would react with iron derived from steel and making a black precipitate of iron sulfide. But it could easily be a fungus, base on simple calculations 8 g/L sulfuric is nearly pH=1, SRB are not that easily found in acidic conditions and even less in so extreme ones. However, I'm working with fungi isolated from mine waters and under extreme conditions most fungi tend to produce melanins (thus, black colour). So, it is likely that a fungus wuld be the base of the biofilm. The most rounded cells could easily be vesicular structures or the formation of conidia, hard to say.
Based on pictures, description and if the liquid didn't start to show orangish colour, I would discard any iron oxidising bacteria suc Acidithiobacillus or Leptospirillum as main organisms. Even more knowing how they dislike organic carbon sources and chloride ions.
By the way, the cells are all collapsed. I had similar problems with some fungi and looked nearly the same. The collapse makes difficult to make any proper guess and images are quite blurry
I just used a pH calculator, though you can do it manually
http://www.endmemo.com/chem/phcal.php
Hello,
We have some results from our initial plate streaks. We have filtered 1ml onto various agars to see if we can get some growth for ID. Results so far:
MLGA & VRBGA - no growth.
RBA & Glucose peptone agar & Biggy agar - mould overgrowth on all three.
TSA (aerobic, microaerobic & anaerobic) - >100cfu/ml on all three.
I'll see if I can get you any images from the light microscope. We have a cmaera on the rig, but it's quite old so I'm not sure what the qulaity will be like but hopefully it will be be able to see something interesting.
Many thanks, Alex