I have heard of commercial available gel for surface decontamination of cadmium. 

Hi Milica,

The Cadmium chloride is soluble in water so you can follow following protocol for cleaning of glass fermenter  vessel.

1) Add water in fermenter glass vessel and keep stirringr on for 30 minutes and followed by decontamination by sterilization at 121 deg. for not less than 45 minutes.

2) After sterilization fill the glass vessel with 0.5N NaOH solution and keep stirring for 2 to 3 hours.

3) Clean with any neutral detergent  following throw cleaning with water and check the conductivity of rinsing water. If the conductivity of water is less than 25 μS ( microsiemens ) than the glass reactor can be used for other fermenter.

Hope this will useful for you.

Mustafa and Atul, thank you so much for useful suggestions!

Dear Atul, if I understand well, this protocol is for SIP fermentor. I am work with Brunswick BioFlo 110, which is auutoclaved in autoclave. So, regarding the first step should be feasible with this fermentor, just to autoclave with water,  without stirring? 

I also found for glassware that can be decontamintaed by keeping in 5% extran for 24hrs, and after rising with water, keeping in 5% nitric acid for the next 24 hrs, so I was wondering if this can be used for fermentor as well.

Dear Milica,

The cleaning  protocol first step , I had requested you to keep stirring to solubilization  of  cadmium chloride and then you can send the fermentor vessel for sterilization by autoclaving ( without stirring) . 

If the fermentor is having in situ sterilization facility that case the stirring is recommended during SIP.

Now the second point I also found 5% (v/v) extran  is good cleaning agent for glass vessel, but I don't having validation data that extran or nitric acid will decontaminated it fully.  

One more point , as per your protocol I think you are consuming approximately  48 hr. While using 0.5N NaOH solution with stirring for 2 to 3 hours and followed by cleaning you can complete the decontamination activity on same day and the fermentor vessel  can be used for next batch.

Dear Atul, 

I am in favour of your protocol for couple of reasons. Thank you for your help. I only had doubts if it can have same succeed rate for both types of sterilization. Once more, thank you for your kind help.