Production optimization characterization of bacterial protease and its application in hide dehairing

Abstract

The proteases are well known for their industrial importance, microorganisms are the best newlinesource of protease. The purpose of present work was to produce the extracellular protease newlinefrom an isolated preferably a bacterial species and its application in hide dehairing. The newlinesoil samples were collected from various places in environment and initial isolation based newlineon zone of hydrolysis on skimmed milk agar media and gelatin agar media, the isolated newlineculture was further screened on casein agar media. The selected isolates after successive newlinescreening further confirmed the protease production on the basis of chicken feather newlinedegradation and shake flask fermentation. The selected bacterial isolates were newlinecharacterized on biochemical and molecular basis and the isolates were found as protease newlineproducers belongs to Bacillus lichenformis SK7 and submitted in NCBI having accession newlineNo. KM206770. Protease production by Bacillus licheniformis SK7 was significantly newlineenhanced by optimizing the media components and culture conditions. Plackett Burman newlineDesign, Central Composite Design and Response Surface Methodology were employed to newlineobtain the optimal medium having the composition of skimmed milk (11.6 g/L), glycerol newline(1.16 g/L) and fish meal 7.6 g/L, FeCl3 (0.1 g/L) and pH (10.0); the corresponding newlineprotease production 472 U/ml at 37°C with 48 h incubation. The strain improvement of newlinedeveloped Bacillus licheniformis SK7 was achieved with the combination of physical and newlinechemical mutagen agents i.e., UV + NTG + EMS by gradual mutation and positive newlinemutants selection. The mutant Bacillus licheniformis SK7 (SN43) was successfully newlinedeveloped and found stable having higher production of protease (662 U/ml) under newlineoptimized medium and physical conditions. Scale-up of protease productionfrom shake newlineflask level to a 5 L fermenter to 30 L fermenter to 100 L fermenter was successfully newlinecompleted. The maximum protease production at 100 L fermenter i.e., 795.7 U/ml was newlineachieved with 7% inoculums size, at pH 10, 37ºC incubation temperature, air 1.5 vvm, newlinemaint