Production, Biochemical Characterization and Detergents Application of Keratinase from the Marine Actinobacterium Actinoalloteichus sp. MA-32

摘要

The present study is the first report on poultry feathers as a novel, inexpensive substrate for the production of a thermo- and detergent stable keratinase from a marine actinobacterium belonging to the genus Actinoalloteichus. Medium composition and culture conditions for the keratinase production by Actinoalloteichus sp. MA-32 were optimized using two statistical methods: Plackett-Burman design was applied to find the key ingredients and conditions for the best yield of enzyme production and central composite design used to optimize the concentration of the five significant variables: whole chicken feather, soy flour, MgSO4·7H2O, KH2PO4 and NaCl. The medium optimization resulted in a 19.30-fold increase with a 31.99 % yield with a specific activity of 3842.57 U mg~(-1) and the molecular weight was estimated as 66 kDa. The enzyme was optimally active at pH 8-10 and temperature 50-60 °C and it was most stable up to pH 12 and 10-14 % of NaCl concentration. The enzyme activity was reduced when treated with Hg~(2+), Pb~(2+), Tween-80, 1,10-phenan-throline and EDTA and stimulated by Fe~(2+), Mg~(2+), Cu~(2+), Ca~(2+), Ni~(2+), Mn~(2+), SDS, ethoxylated (9.5EO) octylphenol, DMSO, sodium sulfite and β-mercaptoethanol. The keratinase exhibited a significant stability and compatibility with most of the tested commercial laundry detergents, demonstrating its feasibility for inclusion in laundry detergent formulation. These results suggest that this extracellular keratinase may be a useful alternative and eco-friendly route for handling the abundant amount of waste feathers or for applications in detergent formulation and other industrial processes.