Isolates with multiple PGP-activities in pure culture like Microbacterium natoriense
strain E38 and Pseudomonas brassicacearum strain E8 did not promote plant growth. The most effective
isolate was strain E108 identified as Curtobacterium flaccumfaciens, which increased barley growth up
to 300%. In pure culture strain E108 showed only two out of six plant growth promoting activities and
would have been neglected.