LAUSR

Abstract The utilization of waste has gained momentum in the field of waste management and industrial bioprocess. In this study, waste chicken feet were used as the source for extraction of a natural inducer, i.e. gelatin for the synthesis of proteolytic enzyme gelatinase. Microorganisms with gelatinolytic activity were screened from mixed culture isolates obtained from a local poultry waste dumping site. The strain which had shown maximum activity was identified as Brevundimonas vesicularis MF276770 using 16S rRNA gene sequencing. The composition of chicken feet gelatin was analysed and further characterized by Fourier transform infrared analysis and SDS-PAGE. The maximum gelatinase activity of 18.8 U/mL was achieved for the isolated Brevundimonas vesicularis MF276770 at 12 h under optimized conditions of pH 7, substrate concentration (2%), inoculums age (12 h), inoculum volume (2%, v/v), temperature (50 °C) and RPM (140). The enzyme kinetics parameters Vmax and Km were observed as 7.4 U/mL and 0.422 µmol, respectively. The molecular weight of the produced gelatinase was determined as 67 kDa. The produced gelatinase was employed to strip the gelatin silver layer from X-ray polyester film with 1.93 U/mL of gelatinase activity.