title: [Auto-inducible expression system based on the SigB-dependent ohrB promoter in Bacillus subtilis].
abstract: The reliable production of heterologous proteins is important in the field of industrial biotechnology. This can be achieved by applying auto-inducible gene expression systems. The development of a Bacillus subtilis expression plasmid harboring SigB-dependent ohrB promoter was reported. The expression system was subjected to high cell density cultivation to produce xylanase as a stable model protein. The recombinant strain was cultured in a synthetic medium containing glucose as the carbon source. The exponential fed-batch feeding strategy was applied to prevent substrate inhibition. A sharp increase of xylanase activity (about 6-fold) at the end of the fermentation was observed as a result of sigma factor B (SigB) protein activation, supporting auto-inducibility of the expression system. For the control strain a specific induction of the xylanase activity was not observed. The recombinant strain was capable to offer a 5-fold increase in xylanase activity in comparison with the control strain. In addition, the constructed system displayed catabolite repression resistance ability. This SigB-dependent expression system can be considered as a biotechnology tool and an alternative to eliminate the cost of conventional inducers, e.g. isopropyl-β-galactopyranoside.
authors.forename: R
authors.initials: R
authors.lastname: Panahi
authors.forename: E
authors.initials: E
authors.lastname: Vasheghani-Farahani
authors.forename: S A
authors.initials: SA
authors.lastname: Shojaosadati
authors.forename: B
authors.initials: B
authors.lastname: Bambai
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D061249:Batch Cell Culture Techniques; D003470:Culture Media / Q000737:chemistry; D043364:Endo-1,4-beta Xylanases / Q000235:genetics* / Q000378:metabolism; D025461:Feedback, Physiological; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D007544:Isopropyl Thiogalactoside / Q000031:analogs & derivatives / Q000494:pharmacology; D008969:Molecular Sequence Data; D010957:Plasmids / Q000737:chemistry* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; C079011:SigB protein, Bacteria; D012808:Sigma Factor; D007544:Isopropyl Thiogalactoside; C070641:isopropyl-beta-galactopyranoside; D043364:Endo-1,4-beta Xylanases