Isolation and functional study of potentially probiotic Lactobacilli from Taiwan traditional paocai

The objective of this study was to isolate, characterize and identify lactic acid bacteria (LAB) from Taiwan traditional pickled paocai. A total of 207 acid-producing strains were isolated and identified as catalase negative, Gram positive, with rod or bead shape and immobility by microbial and biochemical tests. None of the assayed strains showed haemolytic and gelatinase activity. Among the isolated LAB, eleven strains were able to survive at pH 2.0 and 0.3% bile salts for 3 h, utilize non-digestible oligosaccharides, show antimicrobial activity against potentially pathogenic bacteria (Bacillus cereus, Micrococcus luteus, Salmonella typhimurium and Staphylococcus aureus), and modulate cytokine production (IL-12 and IL-10) by RAW264.7 macrophage cell. Through 16S rRNA PCR product analysis and API CHL 50 kits analysis, five Lactobacillus plantarum (E1, E38, E40, E51 and E55), five Lactobacillus casei (E7, E15, E30, E33 and E40), and oneLactobacillus rhamnosus (E8) were identified. L. plantarum E51 showed the highest adherence ability and L. casei E33 showed an immunomodulatory effect triggering a proinflammatory type response. The results show their potential probiotic applications in health food industry.   Key words: Screening, fermented vegetables, paocai, probiotic, adhesion, cytokine.