the present invention refers to a biological formulation for complementing an animal feed , which comprises : dry cells of cupriavidus necator or alcaligenes latus bacteria , containing at minimum 40 % of phb and b vitamins , tyrosine , glutamic acid , phosphates and iron , which formulation may further contain the endogenous phb depolymerase enzyme . the process for obtaining the formulation comprises the steps of : producing , by aerobic fermentation , from 32 to 34 ° c ., in a mineral and aqueous fermentative medium containing sucrose , glucose or other sugary streams derived from sugar production , cells of cupriavidus necator or alcaligenes latus bacteria containing at minimum 40 % of phb and b vitamins , tyrosine , glutamic acid , phosphates and iron ; inactivating the cells , thermally , at a temperature from 65 to 90 ° c . for 15 minutes ; and drying the bacteria cells obtained in the previous step .