from David Beighton, Sadaf Rasheed Mughal and Thuy Do writing in Oral Microbial Ecology: Current Research and New Perspectives:
The oral biofilm proliferates in the mouth by primarily utilizing components of saliva as dietary foods are rapidly cleared. The complex microbial community functions in a concerted manner to obtain nutrients, sugars and amino acids, from salivary components including mucins, by the production of a range of glycosidic enzymes including sialidase, β-galactosidase, N-acetylglucosaminidases, α-fucosidase and mannosidases and exo- and endo-proteolytic activities. Degradation of glycans occurs sequentially and in vitro studies indicate that liberated sugars are rapidly transported though evidence of cross-feeding between species, utilizing liberated sugars, is evident. Streptococcus oralis is a species with the greatest ability to deglycosylate both N- and O-linked glycans and has been used extensively in model systems. New research should take advantage of modern high throughput sequencing techniques to determine the biofilm transcriptome of humans receiving defined diet, including fasting, to ascertain the response of the biofilm to in vivo conditions.
Further reading: Oral Microbial Ecology: Current Research and New Perspectives