Use of bacterial AppA as a phytase, in which said AppA retains at least 60% of its activity after heating the AppA for 15 minutes at 60 ° C, where the AppA is expressed in a yeast host cell.Uso de AppA bacteriana como una fitasa, en el que dicha AppA retiene al menos el 60 % de su actividad después de calentar la AppA durante 15 minutos a 60 ºC, en donde la AppA se expresa en una célula hospedadora de levadura.