Isolation and Identification of Lactic Acid Bacteria with Probiotic Activities from Kimchi and Their Fermentation Properties in Milk

Abstract

Lactic acid bacteria obtained from traditional Kimchi were selected on the basis of their caseinolytic activity and lactose usability and examined for availability as a starter in probiotic activity. Thirty-two strains were selected as lactic acid producing bacteria in BCP agar, and two strains (KC23 and KF26) with more than 90% resistance for both acid and bile salts were selected. The two strains were identified as L. plantarum (KC23) and L. paracasei (KF26) by API 50 CHL system and 16S rRNA sequence analysis. L. plantarum (KC23) was finally selected based on its biochemical characteristics for lactose and raffinose usability. Free tyrosine content increased rapidly in 10% skimmed milk medium, from 24.1 μg/mL after 8 h to 43.9 μg/mL after 16 h. Additionally, the caseinolytic clear zone of 12 mm of L. plantarum (KC23) was greater than the 9 mm zone of commercial L. acidophilus CSLA. The bacterium exhibited mesophilic growth and yielded 8.9×10 CFU/mL when incubated at 37°C for 12 h at pH 4.25. Moreover, L. plantarum KC23 exhibited antibacterial activity as it formed a clear zone of 8–13 mm for the 5 pathogens. Adherent activity was 2.23 fold higher than that of LGG. The acidity of 10% skimmed milk fermented for 12 h was 0.74%.