Cloning of the Thermostable Cellulase Gene from Newly Isolated Bacillus subtilis and its Expression
June 27th, 2008 | by admin |Cloning of the Thermostable Cellulase Gene from Newly Isolated Bacillus subtilis and its Expression in Escherichia coli.
A bacterial strain with high cellulase activity (0.26 U/ml culture medium) was isolated from hot spring, and classified and named as B. subtilis DR by morphological and 16SrDNA gene sequence analysis. A thermostable endocellulase, CelDR, was purified from the isolated strain. The optimum temperature of the enzyme reaction was 50 degrees C, and CelDR retained 70% of its maximum activity at 75 degrees C after incubation for 30 min. The putative gene celDR, consisting an open reading frame (ORF) of 1,524 nucleotides and encoding a protein of 508 amino acids with a molecular weight of 55 kDa, was purified from B. subtilis DR and cloned into pET-28a for expression. The cellulase production in E. coli BL21 (DE3) was enhanced to approximately three times that of the wild-type strain.
Li W, Zhang WW, Yang MM, Chen YL.
College of Animal Sciences, Northwest A&F University, Yangling, 712100, People’s Republic of China.