| Autor: |
Kim T; Department of Food and Nutrition, Dongduk Women's University, Seoul 02748, Republic of Korea.; Pulmuone Institute of Technology, Cheongju 28220, Republic of Korea., Heo S; Department of Food and Nutrition, Dongduk Women's University, Seoul 02748, Republic of Korea., Lee JH; Department of Food Science and Biotechnology, Kyonggi University, Suwon 16227, Republic of Korea., Jeong DW; Department of Food and Nutrition, Dongduk Women's University, Seoul 02748, Republic of Korea. |
| Abstrakt: |
Weizmannia coagulans can be used as a starter strain in fermented foods or as a probiotic. However, it is salt-sensitive. Here, W. coagulans genomes were compared with the genomes of strains of Bacillus species ( B. licheniformis , B. siamensis , B. subtilis , and B. velezensis ) that were isolated from fermented foods and show salt tolerance, to identify the basis for the salt-sensitivity of W. coagulans . Osmoprotectant uptake (Opu) systems transport compatible solutes into cells to help them tolerate osmotic stress. B. siamensis , B. subtilis , and B. velezensis each possess five Opu systems (OpuA, OpuB, OpuC, OpuD, and OpuE); B. licheniformis has all except OpuB. However, W. coagulans only has the OpuC system. Based on these findings, the opuA and opuB operons, and the opuD and opuE genes, were amplified from B. velezensis . Expression of each of these systems, respectively, in W. coagulans increased salt-tolerance. W. coagulans expressing B. velezensis opuA , opuD , or opuE grew in 10.5% NaCl (w/v), whereas wild-type W. coagulans could not grow in 3.5% NaCl. The salt resistance of B. subtilis was also increased by overexpression of B. velezensis opuA , opuB , opuD , or opuE . These results indicate that the salt-susceptibility of W. coagulans arises because it is deficient in Opu systems. |
