Title : Novel pH-inducible transcription factors for regulating the expression of cellulase in filamentous fungus Talaromyces pinophilus
Abstract:
Talaromyces pinophilus NCIM 1228 is a potent source of cellulolytic enzymes, though its production efficiency is tightly regulated by complex intrinsic and extrinsic factors. This strain offers substantial possibilities for molecular-level optimisation because of its extensive enzyme consortium that can completely degrade cellulose. Since ambient pH is a crucial environmental factor that affects fungal survival, secretion, and regulatory signalling, pH also has a major impact on the underlying molecular networks that control the expression and activity of enzymes. Therefore, we looked at how ambient pH affected T. pinophilus enzyme profile in this work. In this study, we investigated the influence of ambient pH, a critical environmental factor for fungal survival and secretion, on the enzymatic profile of T. pinophilus. Upon cultivating the strain across a controlled gradient (pH 4.0 to 7.0), we observed a distinct metabolic pivot: while endoglucanase and exoglucanase reached their peak at pH 5.0, the production of beta-glucosidase and xylanase transitioned to a peak at pH 5.5. To elucidate the molecular mechanisms driving these pH-specific variations, transcriptomic analysis was performed. Results highlighted the significant up-regulation of key regulatory elements at pH 5.0 and 5.5, including the activating transcription factor atf21, the positive cellulase regulator Clr2, and the spore-forming transcription factor NosA. These findings suggest a coordinated regulatory network, likely involving the pH-responsive factor PacC, which synchronizes metabolic signaling with enzyme expression. This study provides a molecular foundation for optimizing cellulase yields in T. pinophilus through ambient pH control.
