The purpose of the present investigations was to improve the yield of alkaline protease for leather dehairing by
subjecting the indigenous proteolytic strain Bacillus licheniformis N-2 to various mutagenic treatments viz. UV
irradiations, NTG (N-methyl-N-nitro-N-nitrosoguinidine) and MMS (methyl methane sulfonate). After screening on
skim milk agar plates, a total of nine positive mutants were selected for shake flask experiments. Among these, the
best proteolytic mutant designated as UV-9 showed 1.4 fold higher alkaline protease activity in preoptimized growth
medium than the parent strain. The fermentation profile and kinetic parameters such u(h-1), Yp/s, Yp/x, Yx/s, qs, Qs, qp
and Qp also indicated the superiority of the selected mutant UV-9 for alkaline protease production over the parent
strain and rest of the mutants. The dehairing capability of mutant UV-9 alkaline protease was analyzed by soaking
goat skin pieces for different time intervals (3-15 h) at 40 oC. A complete dehairing without degradation of collagen
was achieved after 12 h, indicating its commercial exploitation in leather industry.
