A sandwiched-culture technique for evaluation of heterologous protein production in a filamentous fungus

Aspergillus niger is known for its efficient excretion machinery. However, problems have often arisen in obtaining high amounts of heterologous protei ns in the culture medium. Here we present a quick method using sandwiched c olonies to evaluate transgenic strains for secretion of heterologous protei ns. Expressing the ABH1 hydrophobin of Agaricas bisporus in A. niger; we sh owed that low production levels of the heterologous protein are probably du e to extracellular proteolytic degradation of the protein.