Characterization of inulinase promoter from Kluyveromyces marxianus for intensive protein expression in industrial biotechnology

Inulinase from Kluyveromyces marxianus (KmINU1) has wide application in industrial biotechnology, and it is supposed that its expression is regulated at the transcriptional level via the promoter. Therefore, in this study, the KmINU1 promoter, fused to the reporter EGFP gene, was analyzed to determine its fundamental regulatory mechanisms in Saccharomyces cerevisiae S288C (ATCC 204508). Induction by inulin and repression by high glucose concentrations of KmINU1 promoters are reported, and the promoter with a length of 353 bp was shown to have the highest strength with the weakest responses to high glucose concentration. Responses of the KmINU1 promoter to carbon source were shown to be related to the Mig1 binding site extending from -496 to -485 bp. Hence, we propose clear regulation mechanisms of the inulinase promoter, which may provide a powerful theoretical reference for its application in protein production.