Project description:The present work aimed at discovering xylose-inducible and glucose-insensitive promoters from Geobacillus thermoglucosidasius DSM 2542. This strategy enabled the pathway from xylose metabolism to riboflavin production activated by xylose but not glucose, so that glucose was mainly used for cell growth while xylose was used for riboflavin production. By performing whole genome transcriptional analysis of G. thermoglucosidasius DSM 2542 with or without 1% xylose, 71 xylose-activated genes were identified which were controlled by 39 putative promoters. 3 experimentally validated xylose-inducible and glucose-insensitive promoters covering a broad range of transcriptional levels were used to activate the extra pathway from xylose metabolism to riboflavin production. Fermentation results showed the good performance of these promoters for riboflavin production improvement comparing to constitutive promoters. Therefore, our strategy could be applicable to the construction of cell factories that can efficiently use natural carbon sources with glucose and xylose components for the production of high-value chemicals.
