Anti-bacterial component dipicolic acid measured in Natto and Natto bacilli

Abstract

In commercially obtained natto and experimentally-prepared natto preparations, relatively high concentrations of dipicolic acid, 20.55 ± 13.67 mg/100 g natto (0.006-0.048%, wet weight) were detected, using a simple method combined with ion-exchange column and colorimetric assay procedures. These values were less than that of the previous data (0.06-0.20%, wet weight) reported 60 years ago. Dipicolic acid was thought to be an intracellular component of natto bacilli and could be extracted in the water-soluble fraction by heat-treatment of the sample for 30 min at 120°C. Furthermore, the partially purified material from natto bacilli caused very strong inhibition of the growth of sake yeasts (Kyokai 7 and Kyokai 9 mutant).