Efficient extraction of chitin from shrimp waste by mutagenized strain fermentation using atmospheric and room-temperature plasma

Chitin extraction from shrimp waste by protease-producingmicroorganisms was a positive and simple method. To improve the protease activity of microorganismused for the extraction of chitin, atmospheric and room temperature plasma technology was adopted to induce mutations in Exiguobacterium profundum, a proteaseproducing bacterium, which was isolated from traditional fermented shrimp paste. After several rounds of screening, the mutant numbered 10017 was screened. The hereditary properties of the mutant were found to be stable after a series of passages. This strain was subsequently used in the deproteinization process, which could remove 91.48% +/- 2.60% protein, and the chitin recovery was 70.18 +/- 2.68%. Fourier transform infrared spectrometry, X-ray diffraction, and scanning electron microscopy was adopted to compare the characteristics of the chitin extracted from mutagenized and wild-type strain fermentation. The crystallinity indices were 80.72% and 82.46%, and the degrees of deacetylation were 15.78% and 27.84%. These results indicated that the deproteinization bymutagenized strain fermentationmight be applied to the production of chitin. Thus, the present study provides an appropriate strategy to develop an efficientmethod to improve protease activity in microbial fermentation. (C) 2019 Published by Elsevier B.V.