Non-traditional sources for isolation of lactic acid bacteria

Abstract

In recent years there has been increasing interest in lactic acid bacteria isolated from non-dairy products, due to their diverse metabolic profile, unique flavor-forming activities, and potential for use as starters or starter adjuncts for the dairy industry. Screening of 400 microbial isolates obtained from the herbs Geranium sanguineum L., Hypericum perforatum L., and Panax ginseng C.A. Meyer was performed, and 64 isolates were selected based on milk coagulation and gas formation ability and non-specific odour. Using tests involving multiple transfer and growth in selective and differential media, 258 single colonies were isolated, of which 98 were affiliated with the lactic acid bacteria group. These bacteria are homofermentative cocci and rods with a wide pH (5.0–9.6) and temperature range (15–45 °C), high salt tolerance (3.0–10.0 % NaCl), and high acid-producing activity (3.50–12.00 g/L). With the use of genotype-based methods, the plant isolates were identified at the species level as Enterococcus faecium, Streptococcus thermophilus and Lactobacillus rhamnosus.