Abstract:

Strain YT9 with high-yield cellulase was screened from coastal soil samples, and the morphological,
physiological and biochemical characteristics as well as 16S rDNA sequence homology of the selected strain were
studied. Finally, the strain was identified as Exiguobacterium sp. Meanwhile, medium composition and culture
conditions for cellulase production were optimized. The optimal medium for higher production of cellulase consisted
of 20 g/L glucose, 0.5 g/L CMC, 8 g/L tryptone, 2 g/L ferrous alum, 2 g/L K2HPO4, 2 g/L NaH2PO4, and 1 g/L MnSO4.
The maximum activity of CMCase was 226.27 U/mL at pH 6.5, 30 ℃ and 4% inoculum. At the same time, the activities of
cellobiohydrolase and β-glucosidase were lower than the endoglucanase activity.

Key words: Exiguobacterium sp., cellulase, optimization, isolation, identification