Associate Professor
Hoang D. Nguyen
Director, Center for Bioscience and Biotechnology, University of Science - VNUHCM, Vietnam
Title of the talk: Bacillus subtilis expression systems and potential applications as vaccine delivery vectors
Abstract
Bacillus species are essential hosts for the production of proteins at industrial levels; 60% of industrial enzymes are produced from these species. Bacillus subtilis, a model Gram-positive bacterium, is considered GRAS, endotoxin-free, allowing high protein secretion. This bacterium can be used as probiotics for humans and animals. The recent development of molecular biology has potentially opened a new approach to exploiting this bacterium. In this study, we want to introduce the expression systems for these bacteria and the study to apply them as vaccine delivery vectors. The B. subtilis expression systems to produce proteins in the cytoplasm, in the culture medium, and on the surface of vegetative cells and spores have been developed and applied as vaccine delivery vectors. We have focused on characterizing promoter elements to range the robustness of promoters in producing mRNA and the seeking mRNA stabilizing elements to enhance the stability of the mRNA leading to high production levels of recombinant proteins in B. subtilis. This study also introduced expression vectors for overexpression of recombinant proteins in the cytoplasm, in the culture medium and on the cell surface of B. subtilis cells using episomal plasmids or integration vectors. The target proteins could be expressed in inducible and inducer-free manners. As an example of the application of the B. subtilis expression system, the authors introduce some data about the generation of B. subtilis strains expressing antigens in the cytoplasm, in the culture medium, and on the cell surface of the vegetative cells and spores. The antigen-expressing B. subtilis strains were introduced mucosally into appropriate animals, and the immune responses and antibody levels were measured. The animal immune response study showed that the antigen-expressing B. subtilis strains could deliver the antigen and induce the immune response.
Biography
Dr. Nguyen Duc Hoang obtained his Ph.D at the Department of Genetics, University of Bayreuth, Germany (9/2003-7/2006) for the work on B. subtilis “Construction of plasmid-based expression and secretion vectors and study of the immobilization of proteins on the surface of B. subtilis cells”. Consequently, the first commercial expression plasmids, pHT series, for B. subtilis, was generated, and the expression vectors using controllable stabilizing elements combined with promoters to enhance protein expression level have been developed. In 2006, he moved to the Max Planck Institute for Molecular Physiology. He has been working for the University of Science-VNUHCM since 6/2011. He was Head of the Department of Microbiology from 2012 – to 2021 and was appointed as an associate professor in 2015. He is currently the director of the Center for Bioscience and Biotechnology. He has started working on the Bacillus subtilis expression system since 2003, and his research group currently focuses on gene expression in B. subtilis in different locations, in the cytoplasm, on the surface of vegetative cells and spores, and as secretion into the culture medium. His research group also focuses on vaccine development for cattle and fish using B. subtilis as a vaccine delivery vector.
Publications: ORCID, Researchgate, ResearchID.