Hereditary Fructose intolerance is a rare genetic disorder, caused by a deficiency in Aldolase B, leading to liver or kidney failure after fructose uptake. We will genetically modify the probiotic Lactobacillus johnsonii to metabolize fructose and sucrose instead of glucose in order to effectively remove these metabolites. Therefore, we will knock out enzymes involved in glucose metabolism and increase the uptake and metabolism of fructose and sucrose. In order to avoid a significant impact on growth rates we will select suitable knockout targets based on an analysis of in silico models of closely related species. Since cloning is the main work in both our and most other iGEM projects, we want to make cloning faster, easier, and cheaper. We will achieve this by creating backbone inserts for a new plasmid series, that will allow the use of negative selection and a novel plasmid purification technique with the iGEM 3A assembly.