EFFICIENT EXPRESSION AND SECRETION OF RECOMBINANT ALPHA-AMYLASE IN PICHIA-PASTORIS USING 2 DIFFERENT SIGNAL SEQUENCES

We have cloned and expressed a bacterial thermostable alpha amylase ge ne in Pichia pastoris using the methanol-controlled alcohol oxidase (A OX1) promoter. Two integrative vectors were constructed with two diffe rent secretion signal sequences in order to obtain efficient secretion of the protein. One vector contains the structural gene encoding the mature alpha amylase fused to the SUC2 gene signal sequence from Sacch aromyces cerevisiae. In the other vector, the alpha amylase is express ed with its own signal sequence. In both cases, the alpha amylase were secreted into the culture medium with high efficiency, around 2.5 and 0.9 g/l respectively.