pH Tolerance of antifungal producing lactic acid bacteria

Abstract

Four isolates of lactic acid bacteria (LABs), i.e. L14, L25, L26 and L31, were identified as Pediococcus pentosaceus 1, Pediococcus acidilactici, Lactococcus lactis ssp. lactis 1 and Pediococcus acidilactici, respectively, using the biochemical commercial test kit, API50CHL. All isolates were screened for the presence to study on effect of antifungal activity against indicator fungi (Rhizopus spp., Aspergillus spp. and Candida albicans) by means of double layer (over lay) and agar well diffusion. The results revealed that all of them inhibited the growth of all fungi by the overlay method, but no growth inhibition was observed when using culture broth. This may be because of the instability of metabolites and molecular weight of metabolites, etc. However, these isolates may be used as probiotics because they can resist to acidic or basidic conditions ranging from pH 4 to pH 11, similar to environmental conditions in human stomach and intestine.