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Figure 4: Screening and characterization of halophilic bacterial isolates for glutaminase production. (a) Equal number of cells of all halophilic bacterial isolates was inoculated in LB medium supplemented with 1% L-glutamine, phenol red, and 1 M NaCl the medium. The tubes were incubated at 30°C for 24 hours to visualize glutaminase activity. The change in colour of medium from yellow to pink indicates glutaminase activity. Effect of NaCl, pH, and temperature on glutaminase activity of halophilic isolates: the specific glutaminase activity (U/mg) of the bacterial isolates Shewanella algae SS2, Halobacillus trueperi SS3, Halomonas venusta SS5, and Marinomonas sp. SS8 was plotted against the different concentration of sodium chloride (NaCl) (b), varying pH (c), and temperature (d) as indicated. In each panel, the data represent an average of three independent experiments with standard deviation.