Abstract:

A -mannanase producing bacterial strain HDYM-04 was isolated from laboratory-prepared flax retting liquor. HDYM-04 was identified as Bacillus licheniformis according to physiological and biochemical tests and phylogenetic analysis based on16S rDNA sequence. Single factor and orthogonal array design experiments were performed to obtain the optimum fermentation conditions for -mannanase production: culture with an inoculation size of 2% for 48 h at 37 in a 250 ml shaking flask filled with 100 ml liquid medium consisting of 60 g/L konjac powder utilized as carbon source, 30 g/L peptone utilized as nitrogen source, 0.2 g/L MgSO4 7H2O, 5 g/L K2HPO4 at initial pH 8.0. Under these optimum conditions, a -mannanase activity of 4890 U/ml fermentation broth was achieved, which was 3.2 times higher than before the optimization.

Key words: β--mannanase , 16S rDNA , optimization , orthogonal array design