Chaolei Zhang1, Chao Wang2, Shan Zhao3, Zhilong Xiu4. 1. School of Life Science and Biotechnology, Dalian University of Technology, Linggong Road 2, Dalian, 116024, China. 2. Laboratory of Environmental Technology, INET, Tsinghua University, Beijing, 100084, China. 3. Dalian Institute of Chemical Physics, Chinese Academy of Science, 116023, Dalian, China. 4. School of Life Science and Biotechnology, Dalian University of Technology, Linggong Road 2, Dalian, 116024, China. zhlxiu@dlut.edu.cn.
Abstract
OBJECTIVES: Probiotics (Bacillus subtilis 04178) were entrapped in alginate-chitosan microcapsules by high-voltage electrostatic process. The encapsulation pattern was established as entrapped low density cells with culture (ELDCwc). The performance of ELDCwc cells was investigated against stress environments of simulated digestive fluids. RESULTS: After incubation in simulated gastric (pH 2.5) and intestinal fluids (4% bile salt) for 2 h, the survival rate of ELDCwc cells (18.19% and 27.54%) was significantly higher than that of the free cells (0.0000009% and 0.0005%). The reason why B. subtilis embedded in microcapsules can resist the stress environments was that the mass production of extracellular proteins and polysaccharides prompted B. subtilis to form cell aggregates. The production of extracellular proteins and polysaccharides were regulated by the concentration of c-di-GMP and the expression of ydaJKLMN operon, abbA, sinI, slrA, slrB, abrR and sinR. CONCLUSIONS: c-di-GMP is important for the production of extracellular polymer substance to enhance probiotic viability in stress environments.
OBJECTIVES: Probiotics (Bacillus subtilis 04178) were entrapped in alginate-chitosan microcapsules by high-voltage electrostatic process. The encapsulation pattern was established as entrapped low density cells with culture (ELDCwc). The performance of ELDCwc cells was investigated against stress environments of simulated digestive fluids. RESULTS: After incubation in simulated gastric (pH 2.5) and intestinal fluids (4% bile salt) for 2 h, the survival rate of ELDCwc cells (18.19% and 27.54%) was significantly higher than that of the free cells (0.0000009% and 0.0005%). The reason why B. subtilis embedded in microcapsules can resist the stress environments was that the mass production of extracellular proteins and polysaccharides prompted B. subtilis to form cell aggregates. The production of extracellular proteins and polysaccharides were regulated by the concentration of c-di-GMP and the expression of ydaJKLMN operon, abbA, sinI, slrA, slrB, abrR and sinR. CONCLUSIONS:c-di-GMP is important for the production of extracellular polymer substance to enhance probiotic viability in stress environments.
Authors: Xiaohui Gao; Sampriti Mukherjee; Paige M Matthews; Loubna A Hammad; Daniel B Kearns; Charles E Dann Journal: J Bacteriol Date: 2013-07-26 Impact factor: 3.490
Authors: Nina D Coelho-Rocha; Camila P de Castro; Luis C L de Jesus; Sophie Y Leclercq; Savio H de Cicco Sandes; Alvaro C Nunes; Vasco Azevedo; Mariana M Drumond; Pamela Mancha-Agresti Journal: Front Microbiol Date: 2018-10-05 Impact factor: 5.640