Useful microbes.

https://www.google.es/url?sa=t&rct=j&q=ppt%20microbes&source=web&cd=4&ved=0CCsQFjAD&url=http%3A%2F%2Fwww.e-bug.eu%2Flang_eng%2Fsecondary_pack%2Fdownloads%2Fgm%2Fgmmm1%2FUseful%2520microbes%2520presentation.ppt&ei=TUrSVJyuFoT0UqWNgIgB&usg=AFQjCNGKhmicTTw3mx9apXZWM_YXugLdKg&sig2=IBm_zaa7HkcQGluo6mGlxg&bvm=bv.85076809,d.d24