However, B. cereus BG1, which produced the lowest level (231 U/ml) of protease activity, showed a higher DP (80.9%) rate. The DP and DM rates obtained in this work were higher than those obtained by Jo et al. [26] who reported a DM and DP rates of 84% and 47%, respectively, after 7 days of fermentation of crab shells with Serratia marcescens FS-3. This proves the efficiency of the Bacillus strains used in our study.