Characterization of haloalkalophilic organic solvent tolerant protease for chitin extraction from shrimp shell waste

•Paracoccus saliphilus APCMSTCS5 was isolated & identified from marine environment.•This strain produced Halophilic Organic Solvent tolerant Protease (HOSP).•Purified HOSP displayed better stain removal and antibiofilm activity.•Biofermentation of shrimp shell waste by HOSP strain yielded chitin.•Chitin purity was confirmed through FTIR and 13C CP/MAS NMR analysis.

Halophilic organic solvent tolerant protease (HOSP) producing Paracoccus saliphilus APCMST-CS5 was isolated from the marine sediment samples and identified through 16S rRNA sequence analysis. P. saliphilus APCMST-CS5 registered maximum HOSP production of 1,321.70 U/ml in the medium contained the most significant parameters such as shrimp shell powder (SSP), CaCl2, NaCl, and sardinella powder (SP), obtained through Placket-Burman and Response Surface Methods. HOSP was further purified to 22.68 fold purity with 29.71 U/mg specific activity and its molecular weight was 39 kDa. The HOSP was stable at 60 °C, 9.0 pH, 3.0 M NaCl concentration and it also showed maximum activity at other tested parameters. Interestingly the purified HOSP showed better antibiofilm ability against tested pathogens. Also, the HOSP effectively deproteinized (85.64%) shrimp shell chitin which in turn maximum and exhibited higher antioxidant activity. The commercial and experimental shrimp shell chitin showed similar peak pattern in FTIR and 13C CP/MAS NMR spectral analysis.