Bio-fuels and commercial aviation

[Sriajuda]

So, SLF here. Did a bit of flying, ok. But I have some expertise in other areas. So I have an urgent question to the people who truly know the answer (please no speculations - that's my part):

Is jet fuel (Kerosene) also mixed with "bio-fuel" as in Diesel here in the EU?

If so, that could be extremely dangerous with planes sitting on the tarmac for months, in the baking heat, presumably with not-emptied tanks.
I am an avid sailor, very well connected in the sailing community, and since they started mixing the bio-fuel into the Diesel, we have had a virtual explosion of problemes from this. What happens? Sailboats use their engines quite sparingly. Mostly only for harbor maneuvers. In winter storage, the fuel has ample time to develop bacterial growth. This growth produces large, slimy clots of stuff that can easily block a 1/2 inch fuel line, not to mention filters and injectors. And that is during the *cold* season.

Has anyone looked into that possibility? Because, if my suspicion is right, there are tens of thounands of aircraft sitting on tarmacs that might be ticking time bombs, as flight restrictions are lifted!

Thanks to anybody in the field who can contribute to this question, and possibly raise the alarm.

George, from Germany
This post has been moved from the recent Karachi crash thread to the Tech Log as it really isn't talking about the crash itself, but rather a question regarding the specifics of modern jet fuel. If it is too far out in left field it can certainly be closed.