733 Figure 47- A. niger (A) and P. oxalicum (B) tolerance under different alkalinity conditions. The red dashed line indicates a tolerance index of 0.5. Asterisks (*) represent statistically significant changes. Figure 48- A. niger (A) and P. oxalicum (B) tolerance under different salinity conditions. The red dashed line indicates a tolerance index of 0.5. Asterisks (*) represent statistically significant changes. Figure 49- pH variation of the culture medium after 11 days of incubation with (A) A. niger and (B) P. oxalicum in different alkalinity and salinity conditions. Values are expressed as ΔpH (1õ3)$5H - 1õ)$)>)5H ). Negative ΔpH values represent a reduction in pH (acidification) relative to the initial medium. Means and confidence intervals (95%) are presented. 3.2 Effect Of BR On The Growth Of The Selected Fungal Strains The tolerance of filamentous fungi to BR is a critical determinant of their suitability for both bioleaching and bioremediation applications, and our results demonstrate strong residue-specific and strain-specific responses. A. niger tolerated BR concentrations up to 20% (w/v) in BR-A, 2% (w/v) in BR-B, and 25% (w/v) in BR-C, with growth inhibition increasing with the concentration ( Figure 50). These tolerance limits align with previous reports indicating a maximum BR tolerance of approximately 10% (w/v) for this strain (Kiskira et al., 2023; Qu et al., 2015; Reddy, 2025). Although the initial pH values at limiting concentrations for BR-A, BR-B, and BR-C were below previously established pH tolerance thresholds ( Figure 47.A), inhibition persisted, demonstrating that pH alone does not govern fungal survival. Moreover, despite BR A and BR C showing similar pH after seawater neutralisation ( A) B) A) B)
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