Screening of protease-producing Serratia marcescens FS-3 and its application to deproteinization of crab shell waste for chitin extraction

Serratia marcescens FS-3, isolated from a soil sample in the southwestern area of Korea, exhibited a strong protease activity of 60.7 U/ml after 3 days of incubation. The protein removal from natural crab shell wastes with 10% S. marcescens FS-3 inoculum was 84% after 7 days of fermentation. At the same time, 47% demineralization occurred. When the shell waste was treated with 1% Delvolase® as a reference, deproteinization rate was 90%. In combination of 10% S. marcescens FS-3 culture supernatant and 1% Delvolase®, deproteinization rate of the shell waste was 85%, while the rate was 81% in 10% FS-3 culture supernatant only. These results suggest that bio-deproteinization of the crab shell wastes using S. marcescens FS-3 could be applicable to the chitin production process.