2.4. Enzyme activity of strains
Enzyme activity was assessed using the API ZYM kit (BioMerieux, Marcy l'Etoile, France) (Sharifuzzaman, Al-Harbi, & Austin, 2014). The isolated strains were suspended in sterile saline containing 0.85% sodium chloride at 105 CFU/mL and added to each of 20 cupules. After inoculation, the cultures were incubated at 37 °C for 4 h, and then 1 drop each of the ZYM A and ZYM B reagents were consecutively added to each cupule. Color was allowed to develop for at least 5 min, and values were assigned as the colors developed. The approximate amount of substrate hydrolysis was determined.