Novel biological and chemical methods of chitin extraction from crustacean waste using saline water

Abstract

Abstract BACKGROUND Several techniques have been proposed to recover chitin from shrimp waste using large amounts of freshwater and chemicals. The standard chemical recovery of chitin was first compared by replacing fresh water with seawater. In addition, a biotechnological process with Bacillus subtilis ( B1 ) and Bacillus licheniformis ( B2 ) using seawater during all steps of chitin extraction was studied. RESULTS The demineralization rate ( DM ) was statistically significant when using seawater ( P= 0.000020) and chemical recovery in comparison with deproteinization ( DP ). Increasing HCl concentration (from 1 to 1.28 mol L −1 ) and reaction time (from 60 to 90 min) resulted in DM similar to fresh water ( P >0.05). Highest DP rates were obtained with crude protease ( B1 ; DP ≈74%) and ( B2 : DP ≈84%), when fermentation was carried out for 24 h at an enzyme/substrate ratio of 2. Maximum DP was reached (≈79% for B1 and ≈ 82% for B2 ) after 15 days, while DM ranged between 55 and 60%. CONCLUSION Combined enzymatic DP (with B2 ) followed by a chemical DM process was used to produce chitin ( DP ≈84%, DM ≈94%) which, on transformation to chitosan, showed a degree of deacetylation equivalent to ≈ 71%. This combined approach using seawater could transform crustacean waste into chitin products of commercial value. © 2015 Society of Chemical Industry