Api zym method

Physiological tests such as salinity, pH, and temperature tolerance were performed in liquid medium M2mod. To test the NaCl tolerance, medium M2mod was prepared employing ASW devoid of NaCl. The required NaCl concentrations were adjusted prior inoculation, using a 30% NaCl (w/v) solution. The ASW tolerance was tested using M2mod without ASW. Again, the required concentration of ASW was adjusted prior inoculation. Growth was detected by monitoring the optical density at 600 nm using a Photometer Ultrospec II (LKB Biochrom). Carbon source utilization was tested using the GN2 MicroPlate™ system (Biolog), while enzymatic activities were tested using the API® ZYM method (bioMérieux). The physical features of the cell wall were analyzed by Gram staining, KOH test and Bactident® Aminopeptidase test strips. Growth under anoxic conditions was investigated using the api® 20 NE system (bioMérieux) according to the manufacturer's instructions.

The enzymatic activity profiles of the Ent+ or m-Ent+ Enterococcus and the control LAB strains (Table 1) were determined by the API ZYM method (BioMerieux, Marcy l’ Etoile, Lyon, France) at 37 °C for 4 h, according to the manufacturer’s instructions.