Screening for Cellulolytic Bacterial Strains

To determine the cellulolytic activities of the tested bacteria, cultures were grown overnight (OD₆₀₀ ∼0.5) and spot-inoculated in triplicates of 5 µL on plates with solid Mandels and Reese medium (Mandels and Reese, 1957 (link)) containing carboxymethyl cellulose (CMC) sodium salt (Sigma-Aldrich) (Liang et al., 2014 (link)). Bacteria were then incubated at 20°C for 7 days. After the incubation time, plates were flooded with an aqueous solution of Congo red (1 mg/ml) for 15 min. The Congo red solution was then poured off and visualised zones of hydrolysis were stabilised by flooding the agar with 1 M HCl (Teather and Wood, 1982 (link)).