Recombinant Lactobacillus spp. expressing sweet-tasting protein, Brazzein

초록

Sucrose overuse is involved with several health-related problems such as obesity, caries, and diabetes mellitus, while artificial sweeteners have other problems including cancer. Because of these problems interest in alternative natural sweeteners increased steadily. Brazzein is one of the intensely sweet-tasting plant proteins which consists of 54 amino acids. In this study, we expressed brazzein in Lactobacillus spp. that are primary member of probiotics and widely used in food industry. First, we conducted electroporating pMSP3545 vector which contains brazzein gene along with nisin-controlled expression system (NICE) into three Lactobacillus spp. (L. paracasei KLB58, L. plantarum KLB213 and L. reuteri KCTC3594). We successfully confirmed brazzein expression in Lactobacillus spp. using Western blot analysis. Overall, higher expression rate was obtained with induction time of 3~4hr, and nisin concentration of 25~40ng/ml. Also, expression rate of brazzein in Lactobacillus spp. was over two times greater than that in Lactococcus lactis. To our knowledge, this study represents the first report on the construction of recombinant Lactobacillus spp. expressing brazzein and further studies are necessary to remove antibiotic resistance marker gene before the recombinant Lactobacillus spp. are applied in food industry.