The pheB gene from Geobacillus stearothermophilus DSM6285 has been exploited as a reporter gene for Geobacillus spp. The gene product, catechol 2,3dioxygenase (C23O), catalyses the formation of 2-hydroxymuconic semialdehyde which can be readily assayed. The reporter was used to examine expression from the ldh promoter associated with fermentative metabolism.
Bartosiak-Jentys, J., Eley, K., & Leak, D. J. (2012). Application of pheB as a reporter gene for Geobacillus spp, enabling qualitative colony screening and quantitative analysis of promoter strength. Applied and Environmental Microbiology, 78(16), 5945-5947. https://doi.org/10.1128/AEM.07944-11