Isolation and characterization of lactic acid bacteria from traditional fermented bamboo shoot

Abstract:

Nearly 62% of households in the northern highland regions of Thailand rely on naturally fermented bamboo shoot as a daily condiment, yet the microbial communities responsible for this fermentation remain poorly catalogued. This research isolated and characterized Lactic Acid Bacteria (LAB) from traditionally prepared fermented bamboo shoot (locally called naw mai dong) collected from four villages in Chiang Mai province, northern Thailand, during July-November 2023. A total of 87 LAB isolates were recovered on de Man-Rogosa-Sharpe agar, and 23 morphologically distinct colonies were selected for further testing. Biochemical profiling and 16S rRNA gene sequencing identified six dominant species: Lactobacillus plantarum (34.7%), Lactobacillus brevis (22.1%), Lactobacillus fermentum (17.8%), Pediococcus pentosaceus (14.3%), Lactobacillus casei (6.9%), and minor taxa (4.2%). Isolates were screened for acid tolerance (pH 2.5 and 3.0), bile salt resistance (0.3% oxgall), autoaggregation capacity, and antimicrobial activity against five food-borne pathogens. Two strains L. plantarum LP-1 and L. brevis LB-1 survived pH 2.5 for 3 h at rates above 78%, tolerated 0.3% bile for 4 h, and showed inhibition zones exceeding 14 mm against Escherichia coli and Staphylococcus aureus. These traits suggest potential probiotic application in functional food development.