Chitin extraction from crab shells by two-step fermentation with Lacticanttacllus pantarum and Pseudomonas aeruginosa

Abstract

Abstract There are few reports on the extraction of chitin from crab shells using microbiological methods. In this work, the strain Lacticanttacllus pantarum (LA01) for demineralization (DM) and the strain Pseudomonas aeruginosa (PS01) for deproteinization (DP) were screened from soil, seawater, mud of aquaculture farm, seamount, marine cold spring, probiotic powders, etc. After optimizing the fermentation conditions, LA01 showed the highest activity under the conditions of 2% glucose, 1g crab shells of 18 mesh in 100mL system for 48h, while PS01 performed best with 0.5g crab shells of 60 mesh in 100mL system for 48h. chitin was extracted from crab shells using two-step fermentation method with two scheme: (i) LA01 followed by PS01; (ii) PS01 followed by LA01, and the products were analyzed by FTIR, XRD and SEM. Results showed that 97.55 ± 0.15% of DM and 73.49 ± 0.25% of DP were eliminated by inoculating PS01 followed by LA01. The strong connection between protein and chitin in the crab shells was speculated as the reason of protein residues. Similar structure was observed in the fermented product by the results of FTIR and XRD compared with commercial chitin, indicating the structure of α-chitin. The presence of porous and fibrous structures was observed in crab chitin by two-step fermentation using SEM. The fermentation broth acquired from LA01 contained with various organic acids, lactic acid mostly, with contents of 4238.65mg/L, along with 356.91mg/L acetic acid, which has potential application in inhibiting other bacteria pollution during fermentation.