A new protocol to detect cellulase enzyme activity using picric acid in biological samples was considered. •. The protocol is exceptional in its reliance on a few chemicals at low concentrations. •. The new protocol eliminates interference. Cellulose is a heterogeneous polysaccharide and its enzymatic hydrolysis requires endoglucanase, exoglucanase cellobiohydrolase and β-glucosidase to function. Commonly used tests for individual enzymes and cellulase mixture. Key words: b-Glucosidase, Cellobiase. Here, a new cellulase detection protocol is described that circumvents the problems observed with popular agar-based methods by exploiting the ability to, The isolate produced a maximum amount of cellulase and showed a maximum enzyme activity of 0, 98. 97 mol ml − −1, h incubation period, This PCA - cellulase method uses sodium hydroxide instead of sodium carbonate to provide alkalinity to the reaction solution, thereby increasing the stability of the picramic. Mainly, microorganisms secrete three types of enzymes such as endoglucanases and exoglucanases. , and beta-glucosidase for cellulose hydrolysis, cellulases are composed of at least three major groups of enzymes, namely endoglucanases, exoglucanases and β-glucosidases. On the other hand, a new protocol for detecting cellulase enzymatic activity using picric acid in biological samples was considered. Néron et al. 35 developed an assay to quantify cellulase activity in commercial preparations based on the amperometric measurement of β-d-glucose, the end product of cellulose hydrolysis. This method has a. The cellulase activity profile of the enzyme was determined using the crude enzyme source obtained according to the previous protocol Malik et al. 2021. Cellulase activity was measured by the amount of reducing sugars released per ml of sample per minute under analytical conditions.