A New Black Aspergillus Species, A. vadensis , Is a Promising Host for Homologous and Heterologous Protein Production

Abstract

A new species of the group of black aspergilli, Aspergillus vadensis , was analyzed for its potential as a host for homologous and heterologous protein production. Unlike the other black aspergilli, this strain does not acidify the culture medium when nitrate is the nitrogen source and only produces very low levels of extracellular proteases, mainly serine metalloproteases. The stability of A. tubingensis feruloyl esterase A (FaeA) was compared upon production in wild-type A. vadensis , A. tubingensis , and an A. niger strain in which the three main protease-encoding genes were disrupted. The production of FaeA in A. vadensis resulted in larger amounts of intact protein than production in A. tubingensis and was similar to production in an A. niger protease disruptant, confirming in vivo the low proteolytic activity of A. vadensis . The protoplast formation and transformation efficiencies of A. vadensis were much higher than those of A. niger . These characteristics make A. vadensis a very promising candidate for homologous, and possibly heterologous, protein production.