beta-D-fructose 1,6-bisphosphate + H2O = beta-D-fructose 6-phosphate + phosphate Binds 2 magnesium ions per subunit. Carbohydrate biosynthesis; gluconeogenesis. Homotetramer. There are two genes for FBPase in R.capsulatus. Belongs to the FBPase class 1 family.