We then cultured the isolates on medium with Congo red and carboxymethylcellulose (CMC) to assess whether they could degrade cellulose. The two isolates were cultured on CMC plates for 4 days and CMC Congo red plates for 6 days. After flooding the plates with Gram’s iodine for 5 minutes, both isolate colonies showed clear and distinct zones, indicating that they were both capable of cellulose degradation (Fig. 4c–d).