Studies on the Production of Bacterial Cellulases

Abstract

Forty-three soil samples were collected from different Egyptian governorates from which one hundred and sixty-seven isolates, with the characteristic morphology of Genus Streptomyces, were recovered. One hundred and sixty-five isolates of them were mesophilic (28°C), while the other two isolates were thermophilic (49°C). Congo red method was used to confirm the isolates’ ability to produce cellulase. According to the clear zones diameter formed around the isolates, they were classified into five groups; very strong (17 isolates), strong (99 isolates), moderate (39 isolates), weak (6 isolates), and very weak (6 isolates) producers. The 17 isolates that showed very high cellulase production were submitted to a further quantitative test utilizing dinitrosalicylic acid assay. The highest two producers (S11-6 and TS4-2) were identified by 16S rRNA gene sequencing as Streptomyces coelicoflavus and Streptomyces thermodiastaticus, respectively. Because of the high demand for thermotolerant cellulase and its advantages especially on the industrial scale, the thermophilic strain, Streptomyces thermodiastaticus, was selected to complete the current study.