Modification of a gene encoding hybrid xylanase and its expression in Pichia pastoris

To obtain the protein expression of a hybrid xylanase in yeast, the gene encoding it was modified according to the codon bias of Pichia pastoris and expressed extracellularly in this yeast as an active xylanase, MBtx, exhibited a molecular mass of approximately 35 kDa on SDS–PAGE. The pH behavior of MBtx in terms of both activity and stability was similar to that of Btx, original gene product in Escherichia coli, while a certain difference was observed in optimal temperature for activity and in thermal stability. HPLC analysis revealed the xylan in wheat could be hydrolyzed by MBtx and the major hydrolysis product was xylotriose. These results showed codon usage played a key role in regulating the expression of the hybrid xylanase in P. pastoris and the recombinant hybrid xylanase, MBtx, produced by P. pastoris could be potentially useful in feed industry.