Fig. 2

Effect of Sr²⁺ on cellulase production in RUT-C30 strain. pNPCase activity (a), CMCase activity (b), FPase activity (c), xylanase activity (d), and total protein concentrations (e) of the RUT-C30 strain were examined after culture in MM for 2, 3, or 4 days containing different concentrations of Sr²⁺ (0–120 mM). The final values are presented as the mean ± standard deviation (SD) of three independent experimental results. Asterisks indicate significant differences compared to the control (p < 0.05, according to Student’s t-test). MM, minimal medium