Antifungal metabolites of lactobacilli

In recent years, public concern about indoor mold growth has increased dramatically in the United States. In this study, lactic acid bacteria, which are known to produce antimicrobial compounds important in the biopreservation of food, were evaluated to determine if the same antimicrobial properties can be used to protect wood from mold establishment. Based on biomass measurement, cell-free supernatants from Lactobacillus casei subsp. rhamnosus and Lactobacillus acidophilus grown in deMan Rofosa Sharpe (MRS) broth inhibited 95 to 100 percent growth of three mold - and one stain fungus associated with wood-based building materials. Lactic acid and four unknown compounds £ 1 kDa molecular weight were fractionated from the culture supernatant by thin layer chromatography and high-performance liquid chromatography. Antifungal activity, which was attributed to one or more unknown metabolites, was retained during heating and neutralization. A 1:2 dilution of L. casei supernatant inhibited 100 percent growth of all test fungi.