Phylogeny of fungal hemoglobins and expression analysis of the Aspergillus oryzae flavohemoglobin gene fhbA during hyphal growth.

The fhbA genes encoding putative flavohemoglobins (FHb) from Aspergillus niger and Aspergillus oryzae were isolated. Comparison of the deduced amino acid sequence of the A. niger fhbA gene and other putative filamentous fungal FHb-encoding genes to that of Ralstonia eutropha shows an overall conserved gene structure and completely conserved catalytic amino acids.

Expression of Aspergillus hemoglobin domain activities in Aspergillus oryzae grown on solid substrates improves growth rate and enzyme production.

DNA fragments coding for hemoglobin domains (HBD) were isolated from Aspergillus oryzae and Aspergillus niger. The HBD activities were expressed in A. oryzae by introduction of HBD gene fragments under the control of the promoter of the constitutively expressed gpdA gene.