Substrate	Reference(s)	Comment(s)
4-hydroxybenzoic acid	Crawford, R. L., Bromley, J. W., & Perkins-Olson, P. E. (1979). Catabolism of protocatechuate by Bacillus macerans. Applied and Environmental Microbiology, 37(3), 614–618. https://doi.org/10.1128/aem.37.3.614-618.1979	-
protocatechuic acid	Kasai, D., Fujinami, T., Abe, T., Mase, K., Katayama, Y., Fukuda, M., & Masai, E. (2009). Uncovering the Protocatechuate 2,3-Cleavage Pathway Genes. Journal of Bacteriology, 191(21), 6758–6768. https://doi.org/10.1128/jb.00840-09	-