Genome Annotation and Validation of Keratin-Hydrolyzing Proteolytic Enzymes from Serratia marcescens EGD-HP20

Stabilization and utilization of poultry waste demand efficient biodegradation either by mixture of enzymes or by microbial system that can produce different types of protein-hydrolyzing enzymes. For utilization of this keratinous biomass, in the present study, genome was sequenced and annotated for a bacterium having multiple enzymatic options for hydrolysis of different soluble and insoluble protein fractions of poultry waste. Among the soluble protein substrates, optimum production of enzyme and soluble protein was observed in case of casein, whereas among the insoluble protein substrates, maximum production of enzyme was achieved when broken nails were used. Conditions for enhanced enzyme activity with concurrent degradation of keratin-rich poultry feather waste to protein-rich hydrolysate were optimized for different growth parameters. The bacterium grew well and highest protease production occurred in 144 h at mesophilic temperature (30 °C) and alkaline condition (pH 8-10) with enzyme activities of 134 and 168 U/mL, respectively.