Method to Target and Isolate Mutants of Gram-Positive Bacteria




This technology is a method to modify the genetics of probiotic bacteria. The invention facilitates isolation of mutants of gram-positive bacteria without the use of antibiotics. It can be used as part of the process to generate targeted mutations in probiotic bacteria, which may in turn benefit human health. Current methods used to engineer probiotic bacteria employ the use of antibiotics as selectable markers. Such methods raise concerns related to increased antibiotic resistance, particularly when probiotics produced via antibiotics are used in food or medical products. This method does not add exogenous genes during the selection process and, therefore, no novel genes are added to the organism. The process also does not add selection pressure favoring bacteria, which possess antibiotic resistance genes.


Description of Technology


The global probiotic market will approach $30 billion in 2015. Countries such as India are experiencing rapid growth, where the market is expected to grow 22.6 percent annually until 2015. The dairy industry has been actively promoting research for improved and robust strains of probiotic bacteria, where the use of this technology from Michigan State University can be beneficial. Other industries that may benefit from this technology are medicine manufacturing and biotechnology companies, which can use this process to address the safety issue of antibiotic resistance for commercial production.


Key Benefits

  • Improved food-grade modifications: Achieved through addition or removal of targeted genes via recombination to increase beneficial properties of bacteria, adding to the food’s nutritional value.
  • Safer: The method generates mutants without the use of antibiotic selection and reduces pressure of selection on the bacteria. Therefore, it is less likely that bacteria with antibiotic selection markers will increase in numbers.




This invention will primarily facilitate the dairy industry and dietary supplements industry, which have been keen in their use of probiotic organisms. Other possibilities include research and development to isolate mutant strains in commercial laboratories, where there is a concern of antibiotic resistance developing.


Patent Status


Patent pending




Robert Britton, Jan-Peter van Pijkeren


Tech ID




Patent Information:


For Information, Contact:

Randy Ramharack
Technology Manager
Michigan State University