Abstract

                                Pichia pastoris remains an amicable host for the expression of heterologous protein from eukaryotes. Achieving a high level of expression of yeast in the recombinant host has remained a challenge. Apart from the codon preference of genes and proper protein folding for efficient expression of the heterologous gene, the main bottleneck is to efficiently integrate the heterologous gene into the host DNA. The present study evaluated the choice of available transformation methods such as lithium chloride, electroporation, and spheroplast for efficient integration of xylose reductase (Xr) gene of Candida tropicalis in P. pastoris. The results revealed that electro transformation was found to be an efficient method for the transformation for xr in P. pastoris, yielding 1 x 106 transformants, followed by the lithium chloride method registering 2 x 103 transformants.

Key words : Pichia pastoris; xylose reductase; Transformation