Catalyzes the hydrolysis of fructose 1,6-bisphosphate to fructose 6-phosphate. Is essential for growth on gluconeogenic carbon sources. Also displays a low activity toward glucose 6-phosphate, and fructose 6-phosphate, glycerol 3-phosphate, ribulose 1,5-bisphosphate and myo-inositol-monophosphate are not significant substrates. beta-D-fructose 1,6-bisphosphate + H2O = beta-D-fructose 6-phosphate + phosphate Manganese. Mn(2+) can be replaced by Mg(2+). Inhibited by the monovalent cation Li(+) with an inhibition constant of 140 uM. Also inhibited by AMP and phosphoenolpyruvate and to a lesser extent by phosphate, fructose 6-phosphate, fructose 2,6-bisphosphate, and UDP. ATP and ADP have no significant effects on FBPase activity. Optimum pH is 7.7. Carbohydrate biosynthesis; gluconeogenesis. Homotetramer. The FBPase protein levels during growth on glucose, gluconate, ribose, pyruvate, lacatate, or citrate do not vary much (inferior or equal to two-fold) with respect to the carbon source. Strains lacking this gene are unable to grow on the carbon sources acetate, citrate, glutamate, and lactate and display no detectable fructose-1,6-bisphosphatase activity. Belongs to the FBPase class 2 family. Truncated N-terminus.