Potensi Probiotik Bakteri Asam Laktat dari Sayur Selada (Lactuca sativa) Busuk

Abstract

Lactic acid bacteria (LAB) are bacteria that play a role as probiotics for human and animal health. One of benefit of LAB is that they inhibit pathogenic microorganisms. The purpose of this study was to determine the probiotics potential of LAB isolated from rotten lettuce and their ability to inhibit the growth of human pathogenic bacteria such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans. The potential as probiotics were examined through tolerance in bile salt, effect of pH, and their antimicrobial activity. Simple characterization of colony shape cell shape, and Gram staining were also examined. To isolate LAB, MRS agar with 1% CaCO3 were used in pour plate method. LAB were examined to know it tolerance in bile salt of concentration of 0,1%, 0,3%, 0,5% in pH 2,4, and 6. Antimicrobial activity were examined qualitatively to the selected microbes. Eight isolates were found from the three market places. Five out of eight isolates colony were circular in shape, with entire-edge and white in colony color. Three isolates were irregular in shape, undulate-edge, raised and flat in colony elevation, and yellow in color. One isolate had convex in elevation. Gram staining showed that all isolates were coccus gram positive. The isolates demonstrated a relatively wide tolerance in bile salt. Three isolates MTC6, MTCT8 and PH8 were still viable in pH4-6. Although isolates MTC6, MTC8, and PH8 showed antimicrobe activity to selected microbes, but PH8 showed the most. PS7 inhibited E. coli, P. aeruginosa, S. aureus, and C. albicans growth with inhibition zone of 21,05, 23,7, 6,4 and 42,1 mm, respectively. The result of assay showed that isolates MTC6, MTC8 and PH4 could be developed further as probiotics.