A mutant Pichia pastoris alcohol oxidase 1 (AOX1) promoter of the wild type Pichia pastoris AOX1 promoter (SEQ ID No. 1) comprising at least one mutation selected from the group consisting of: a) a transcription factor binding site (TFBS), b) nucleotides 170 to 235 (−784 to −719), nucleotides 170 to 191 (−784 to −763), nucleotides 192 to 213 (−762 to −741), nucleotides 192 to 210 (−762 to −744), nucleotides 207 to 209 (−747 to −745), nucleotides 214 to 235 (−740 to −719), nucleotides 304 to 350 (−650 to −604), nucleotides 364 to 393 (−590 to −561), nucleotides 434 to 508 (−520 to −446), nucleotides 509 to 551 (−445 to −403), nucleotides 552 to 560 (−402 to −394), nucleotides 585 to 617 (−369 to −337), nucleotides 621 to 660 (−333 to −294), nucleotides 625 to 683 (−329 to −271), nucleotides 736 to 741 (−218 to −213), nucleotides 737 to 738 (−217 to −216), nucleotides 726 to 755 (−228 to −199), nucleotides 784 to 800 (−170 to −154) or nucleotides 823 to 861 (−131 to −93) of Seq ID No. 1, and combinations thereof.