Isolation and screening of proteolytic bacteria from sidoarjo shrimp paste as protease source to extract the collagen from milkfish scales (Chanos chanos)

Abstract

This research aimed to isolate protease-producing bacteria from Sidoarjo shrimp paste for extracting collagen from milkfish scales. This study began with isolation, followed by screening and purification of protease-producing bacterial isolates. Further confirmation of the isolates’ proteolytic indices and the crude protease production, the enzymes’ efficacy in extracting collagen from milkfish scales were tested, followed by pathogenicity and identification using 16S rRNA molecular technique. The study has successfully isolated 15 proteolytic bacterial isolates using skimmed milk agar, but only isolates of TR-10, TR-4.1.1, and TR-15.1 exhibited prospective proteolytic activity based on their corresponding proteolytic indices of 2.96 ± 0.06, 3.10 ± 0.10, and 3.71 ± 0.48. Although the proteolytic activity of isolates TR-10 (0.22 ± 0.05 U/mL) and TR-15.1 (1.07 ± 0.14 U/mL) was high in a salt medium using peptone as the nitrogen source, only the former showed satisfactory activity to extract soluble collagen from milkfish scales. Based on the 16SrRNA, the TR-10 isolate was identified as Bacillus megaterium. The non-pathogenicity of the TR-10 bacterium signified its promising role as a protease source for the halal collagen extraction from milkfish scales.