The SUC 2 gene from Saccharomyces cerevisiae coding for the enzyme Invertase was cloned in Hansenula polymorpha under the control of the alcohol-oxidase (AOX) promoter of Pichia pastoris. The culture conditions for the Invertase production using a fed-batch culture were studied. More than 1,5 x 10(3) U/ml of Invertase (1 g/L) were found to be secreted to cellular periplasmic space. The scale up to 50 L of the fermentative process was done.