Introduction and aims: Cellulases have attracted much interest because of the diversity of their applications in industry. However, the major bottleneck of comprehensive application of cellulase in industry is the high cost of the enzyme production. It is therefore imperative to look for microorganisms that have a high rate of cellulase production. It has been suggested that termite gut microbiota has a significant impact on cellulose degradation. Therefore isolation of cellulase enzyme from the bacteria of the termite gut, which has high ability to produce cellulase enzymes, is economical and can be used in the industry as well. In order to better utilize the enzymes in the industry, enzymes are monitored for activity and thermal stability. This study investigates the effect of temperature on activity and stability of cellulase enzymes isolated from the gut bacteria of termite. Material and methods: First, the cellulase enzyme was extracted from the gut bacteria of the termite and then purified by column chromatography. The optimum temperature for cellulase activity was examined by incubation of the purified enzymes with 0.75% (w/v) CMC at temperatures ranging from 20 to 80°C under standard assay conditions. Thermal stability was evaluated by pre-incubation of the enzymes without substrates for 60 min at temperatures of 20–70°C. The enzyme activity was measured under standard conditions. Results and Discussion: Based on research results, the cellulose enzyme showed the highest activity at 50°C. The enzyme maintained more than 60% of its activity in a broad range of temperature from 20 to 70 °C and demonstrated its highest thermal stability at 40°C. Due to the wide thermal stability, this enzyme is suitable for use in various industries.

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