The synthesis of complex glycans such as human milk oligosaccharides, which ameliorate infant nutrition, and glycoproteins, important for carbohydrate-vaccines development, requires a new biotechnological production platform. In this project a platform technology will be created that eliminates unwanted glycosylations stemming from the production host’s inherent glycosylation metabolism and modifies the host’s lipopolysaccharide structure to eliminate its endotoxin activity.