There are some very limited test flights with bio fuels. But in normal operation biofuels are not added to jet fuel.
That said, even in normal Jet-A1 you can get bacterial or algae growth. Which is one of many many reasons why airplanes either have to be carefully stored, or parked with continuous maintenance requirements including engine runs and maintenance continuation flights. In the airline i work for they have to fly latest every 30 days, which currently is done empty as either maintenance reposition flight to an airport with cheaper parking fees or just a departure, vectors back for an approach and landing at the same airport.