Purification and characterization of four key enzymes from a feather-degrading Bacillus subtilis from the gut of tarantula Chilobrachys guangxiensis

摘要

A feather-degrading bacterium was isolated from the gut of the tarantula Chilobrachys guangxiensis, and was classified as Bacillus subtilis (named Bacillus subtilis CH-1) according to both the phenotypic characteristics and 16S rRNA profile. The improved culture conditions for feather-degrading were 10.0 g l(-1) mannitol, 10.0 g l(-1) tryptone, 0.1 g l(-1) MgCl2, 0.4 g l(-1) KH2PO4, 0.3 g l(-1) K2HPO4, 0.5 g l(-1) NaCl, and 2.0 g l(-1) intact feather, with pH 8.5 and 37 degrees C. In the optimized medium, the intact black feather was completely degraded by Bacillus subtilis CH-1 in 24 h. Furthermore, four kinds of enzymes which include extracellular protease Vpr, peptidase T, gamma-glutamyl transpeptidase and glyoxalmethylglyoxal reductase were identified as having principal roles. Simultaneously, the relationship between the disulfide bond reducing activity (DRT) and the keratinase activity (KT) in B. subtilis CH-1 fermentation system was discussed. This is the first report for a feather-degrading enteric bacterium from tarantula. The identification of the enzymes shines a light on further understanding the molecular mechanism of feather-degrading by microbes. (C) 2014 Elsevier Ltd. All rights reserved.