The microbes Escherichia coli and Pichia pastoris are convenient prokaryotic and eukaryotic hosts， respectively， for the recombinant production of proteins at laboratory scales. A comparative study was performed to evaluate a range of constructs and process parameters for the heterologous intra- and extracellular expression of genes encoding the industrially relevant enzyme galactose 6-oxidase (EC 1.1.3.9) from the fungus Fusarium graminearum. In particular， the wild-type galox gene from F. graminearum， an optimized variant for E. coli and a codon-optimized gene for P. pastoris were expressed without the native pro-sequence， but with a His-tag either at the N- or the C-terminus of the enzyme.
The microbes Escherichia coli and Pichia pastoris are convenient prokaryotic and eukaryotic hosts， respectively， for the recombinant production of proteins at laboratory scales. A comparative study was performed to evaluate a range of constructs and process parameters for the heterologous intra- and extracellular expression of genes encoding the industrially relevant enzyme galactose 6-oxidase (EC 1.1.3.9) from the fungus Fusarium graminearum. In particular， the wild-type galox gene from F. graminearum， an optimized variant for E. coli and a codon-optimized gene for P. pastoris were expressed without the native pro-sequence， but with a His-tag either at the N- or the C-terminus of the enzyme.
