Before try any biochemical test you could check if the 16S rRNA gene is amplified by actinomycete specific primers...

In this way I suggest the primers S-C-Act-0235-a-S-20 and S-C-Act-0878-a-A-19 (Stach, J. E., Maldonado, L. A., Ward, A. C., Goodfellow, M., & Bull, A. T. (2003). New primers for the class Actinobacteria: application to marine and terrestrial environments. Environmental Microbiology, 5(10), 828-841)

After that, and if your intention is seek for a better taxonomic position of your isolates, you could follow the directions found in Stackebrandt, E., Frederiksen, W., Garrity, G. M., Grimont, P. A., Kämpfer, P., Maiden, M. C., ... & Whitman, W. B. (2002). Report of the ad hoc committee for the re-evaluation of the species definition in bacteriology. International journal of systematic and evolutionary microbiology, 52(3), 1043-1047.

Good lucky

you should make the 16s analysis, is better for actinobacteria