So far, studies have found that Oscillatoria, Chlorella pyrenoidosa, Chlorella vulgaris and Shewanella algae are able to break down azo bonds. Because textile waters can have fairly high salt concentrations, the fact that some of these microalgae are adapted to living in saline conditions is a huge advantage to using them.
To try and see whether or not a specific kind of microalgae can degrade dyes or not, to a degree, one only has to add dyes to your microalgae mixture and see what happens. In the case of an experiment with Phaeodactylum tricornutum, which hadn’t been found to degrade dyes yet, this meant creating a microalgae culture, adding the dye in different concentrations, giving the mixture light and continuous mixing, and comparing the colour at the start and end. Unfortunately, this microalgae wasn’t found to be useful in degrading dyes, but there are plenty more which are known to be able to break down dyes!