Extraction of Chitin From Shrimp Shell by Successive Two-Step Fermentation of Exiguobacterium profundum and Lactobacillus acidophilus

Jingwen Xie; Wancui Xie; Jing Yu; Rongyu Xin; Zhenping Shi; Lin Song; Xihong Yang

doi:10.3389/fmicb.2021.677126

Extraction of Chitin From Shrimp Shell by Successive Two-Step Fermentation of Exiguobacterium profundum and Lactobacillus acidophilus

Front Microbiol. 2021 Sep 14:12:677126. doi: 10.3389/fmicb.2021.677126. eCollection 2021.

Authors

Jingwen Xie¹, Wancui Xie^{1

2}, Jing Yu¹, Rongyu Xin¹, Zhenping Shi^{1

2}, Lin Song^{1

2}, Xihong Yang^{1

2

3}

Affiliations

¹ College of Marine Science and Biological Engineering, Qingdao University of Science and Technology, Qingdao, China.
² Shandong Provincial Key Laboratory of Biochemical Engineering, Qingdao, China.
³ Qingdao Keda Future Biotechnology Co., Ltd, Qingdao, China.

Abstract

As an environmentally friendly and efficient method, successive two-step fermentation has been applied for extracting chitin from shrimp shells. To screen out the microorganisms for fermentation, a protease-producing strain, Exiguobacterium profundum, and a lactic acid-producing strain, Lactobacillus acidophilus, were isolated from the traditional fermented shrimp paste. Chitin was extracted by successive two-step fermentation with these two strains, and 85.9 ± 1.2% of protein and 95 ± 3% of minerals were removed. The recovery and yield of chitin were 47.82 and 16.32%, respectively. Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy (SEM) were used to characterize the chitin. The crystallinity index was 54.37%, and the degree of deacetylation was 3.67%, which was lower than that of chitin extracted by the chemical method. These results indicated that successive two-step fermentation using these two bacterial strains could be applied to extract chitin. This work provides a suitable strategy for developing an effective method to extract chitin by microbial fermentation.

Keywords: Exiguobacterium profundum; Lactobacillus acidophilus; chitin; demineralization; deproteinization; shrimp shell; successive two-step fermentation.