Extraction of chitin from Litopenaeus vannamei shell and its subsequent characterization: an approach of waste valorization through microbial bioprocessing

Chemical extraction of chitin is very hazardous and costly which can be overwhelmed by microbial bioprocessing. In this study, potent protease and lactic acid-producing bacteria were screened and identified as Alcaligens faecalis S3 and Bacillus coagulans L2, respectively. Productions of protease and lactic acid by the respective bacterial strains were optimized. The shell of Litopenaeus vannamei was sequentially treated with the partially purified protease and lactic acid and the treatment conditions were optimized for betterment of chitin yield. Spectral characterization by SEM-EDS, IR, XRD, NMR, XPS and thermal characterization by TG and DTG analysis of the extracted chitin was made and compared with commercial one. It was revealed that both the chitin have similar characteristics. Therefore, it can be articulated that chitin can be extracted from crustacean shells in pure form by microbial bioprocessing which will be a good catch for biorefinary industries for chitin extraction through greener route. Graphic abstract