Production of chitin from red crab shell waste by successive fermentation with Lactobacillus paracasei KCTC-3074 and Serratia marcescens FS-3

Successive two-step fermentation was carried out from red crab shell wastes for biological extraction of chitin in combination of the 1st step with a lactic acid bacterium Lactobacillus paracasei subsp. tolerans KCTC-3074 and the 2nd step with a protease producing bacterium Serratia marcescens FS-3, and vice versa. In the 1st step fermentation with KCTC-3074, the pH decreased rapidly from pH 6.90 to 3.31 and TTA increased rapidly to 10.99 for 5 days. At day 7 in the 2nd step fermentation with FS-3, pH further dropped to 2.82 and TTA also dropped to 1.71. In the 1st step fermentation using FS-3, the pH decreased slightly from pH 6.90 to 5.89, and TTA was low as indicated by 1.50 at 5 days. At day 7 in the 2nd step fermentation with KCTC-3074, the pH value was 3.62, and TTA increased to 8.95. The successive fermentation in the combination of FS-3 and KCTC-3074 gave the best result in co-removal of CaCO₃ and proteins from crab shells. In this combination, the rates of demineralization and deproteinization were 94.3% and 68.9%, respectively, at the end of fermentation. To date, this is the 1st report on successive fermentation for biological extraction of chitin from crustacean shells.