Dear Ciara, could you be more pricise?

I worked with a similar sytem in fed batch mode at the wien universitat so maybe I can help you a bit.

I suggest you to give a look to the publications by Seifert and Rittmann 

kind regards 

Annalisa

Dear Ciara,

To my knowledge, without any experience in culturing pure hydrogenotrophic methanogen, formate can be cleaved into hydrogen, therefore, you can use formate if you worry about the low soluble of hydrogen. CO2 is easier to become bicarbonate or carbonate, that's not thing need to be worried. I have some experience in running reactor to stimulate the growth of hydorgenotrophic methanogens with applied voltage that produce hydrogen/electron. If you get interested in this, you can check my publication. I think use electrochemical method to feed bacteria can be a novel idea.

Good luck with you and your experiment. 

Dear Annalisa and Weiwei, 

Apologies I was not getting research gate notifications as it turns out it was linked to my old University account - I had assumed I had no responses! We specifically want to study hydrogenotrophic methanogenesis and need to feed with hydrogen unfortunately. We currently are working with batch cultures but we think for our next experiments a continuous culture would be preferable. We have three Applikon chemostats in our lab but we do not have anyone who knows how to operate them anaerobically. Annalisa thank you - I am about to read papers from the authors you recommended. But perhaps if you have time we could discuss in more detail? Thank you both.