DiscoFungi from the CURB Media company uses bio-florescent bacteria for making visual images. (photo snagged from their website)
CURB (the natural media company) is an interesting organization. My friend Denisa sent me an article about the recent florescent bacteria media campaign and in looking at the company website, they have been responsible for some really amazing works of biological media. They have sculpted sand, snow, dust, grass, you name it -- making eye catching and ecologically safe advertising campaigns and beautiful works of art.
glowfungi - http://www.curbmedia.com/what-we-do-glowfungi.asp
Browse their website for burned grass and even Obama art -- http://www.curbmedia.com