Expression of a pectin lyase A gene from Aspergillus niger in Pichia pastoris GS115

: In this study, the mature peptide sequence of a pectin lyase gene A was amplified from Aspergillus niger strain EIM-6 by using RT-PCR reverse transcription technique. The cloned gene was then inserted into a Pichia pastoris expression vector pPIC9k to produce the recombinant expression plasmid pPIC9K-pelA. By using electric shocks, we successfully transformed the recombinant pPIC9K-pelA into Pichia pastoris GS115. The activity of the engineered strain reached to 2.3 U/mL after induction with the final concentration of 1.5% methanol. SDS-PAGE analysis revealed that the pPIC9K-pelA transformant had an additional protein band of approximately 38 kD, which was not present in the control. There were no significant differences between the recombinant and native pectin lyase with regard to their hydrolysis activities.