Fermentation of L-sorbose by microorganisms of the human dental plaque.

Abstract

Microorganisms with the ability to ferment L-sorbose were recovered from human dental plaque. According to their characterization these bacteria could be identified as Lactobacillus casei. Their fermentation capacity was tested in vitro with L-sorbose as sole carbohydrate source. Sorbose consumption and acid production were both analyzed by high pressure liquid chromatography. The amount of fermentation end product – lactic acid – thus detected is slightly higher than that produced under comparable conditions by Streptococcus mutans with sucrose as carbohydrate source. The cariogenic potential of the combination L. casei – L-sorbose was investigated by gnotobiotic animal experiments. The monoassociation of L. casei with rats fed an L-sorbose diet led to higher caries scores than S. mutans in gnotobiotic rats with a sucrose test diet. However, in conventional animal experiments the cariogenicity of L-sorbose was significantly lower than that of sucrose, but still higher than, e. g., that of xylitol.