Development of a xylose-inducible and glucose-insensitive expression system for Parageobacillus thermoglucosidasius

• Published in: Applied microbiology and biotechnology 2024-12, Vol.108 (1), p.493-493, Article 493
• Main Authors: Wang, Junyang, Wang, Weishan, Chen, Yihua, Liu, Zihe, Ji, Xu, Pan, Guohui, Li, Zilong, Fan, Keqiang
• Format: Article
• Language: English
• Subjects: Applied Genetics and Molecular Biotechnology; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Biology; Biomedical and Life Sciences; Biosynthesis; Biotechnology; Catabolite Repression; Gene expression; Gene Expression Regulation, Bacterial; Glucose; Glucose - metabolism; Life Sciences; Metabolic engineering; Metabolic Engineering - methods; Metabolic flux; Metabolism; Microbial Genetics and Genomics; Microbiology; Parageobacillus thermoglucosidasius; Promoter Regions, Genetic; Riboflavin; Synthetic biology; transcription factors; Vitamin B; Xylose; Xylose - metabolism
• ISSN: 0175-7598; 1432-0614; 1432-0614
• DOI: 10.1007/s00253-024-13333-w

Inducible expression systems are pivotal for governing gene expression in strain engineering and synthetic biotechnological applications. Therefore, a critical need persists for the development of versatile and efficient inducible expression mechanisms. In this study, the xylose-responsive promoter xylA5 p and its transcriptional regulator XylR were identified in Parageobacillus thermoglucosidasius DSM 2542. By combining promoter xylA5 p with its regulator XylR, fine-tuning the expression strength of XylR, and reducing the glucose catabolite repression on xylose uptake, we successfully devised a xylose-inducible and glucose-insensitive expression system, denoted as IExyl*. This system exhibited diverse promoter strengths upon induction with xylose at varying concentrations and remained unhindered in the presence of glucose. Moreover, we showed the applicability of IExyl* in P. thermoglucosidasius by redirecting metabolic flux towards riboflavin biosynthesis, culminating in a 2.8-fold increase in riboflavin production compared to that of the starting strain. This glucose-insensitive and xylose-responsive expression system provides valuable tools for designing optimized biosynthetic pathways for high-value products and facilitates future synthetic biology investigations in Parageobacillus . Key points • A xylose-inducible and glucose-insensitive expression system IExyl* was developed. • IExyl* was applied to enhance the riboflavin production in P. thermoglucosidasius • A tool for metabolic engineering and synthetic biology research in Parageobacillus strains.