Who discovered Biofilm?

Anton Van Leeuwehoek discovered Biofilm.
A biofilm is an assemblage of surface-associated microbial cells that is enclosed in an extracellular polymeric substance matrix. Van Leeuwenhoek, using his simple microscopes, first observed microorganisms on tooth surfaces and can be credited with the discovery of microbial biofilms.
Back in the 17^th century, when Anton Von Leeuwenhoek, the inventor of the Microscope, saw microbial aggregates (now known to be Biofilms) on scrapings of plaque from his teeth. The term 'Biofilm' was coined by Bill Costerton in 1978.