A Biosensor for Human Milk Oligosaccharide Detection

Human milk oligosaccharides (HMOs) are prebiotic compounds found in breast milk that favor the growth of beneficial bacteria in the infant gut. Often these compounds are derivatives of lactose or n-acetyllactosamine that contain either a fucose or sialic acid moiety. While there are many efforts underway to synthesize these beneficial complex carbohydrates, the current standard for their detection is low-throughput HPLC-MS. We present a high-throughput, fluorescence-based detection system for fucosylated and sialylated human milk oligosaccharides in vivo in E. coli. Such high-throughput systems facilitate directed evolution for increased in vivo HMO production. Additionally, the reporter enables the use of HMOs as orthogonal inducers of cellular circuits in synthetic biological applications.