Optimizing oral delivery of next generation probiotics

Probiotic microbes may confer a variety of positive health effects on the host. Until now, development of probiotic products has mainly focused on Lactobacillus and Bifidobacterium species, which generally tolerate the stresses encountered during processing, storage and delivery well. In recent years, newly-discovered gut microbes have gained attention due to their association with healthy host conditions. However, these microbes, designated next generation probiotics, are often oxygen-sensitive, do not tolerate the established product processing techniques, and need protection during delivery and gastric transit. Here, we review the challenges related to development of next generation probiotic products. The applications of current microbial processing and delivery techniques for the oxygen-sensitive next generation probiotics are assessed, and putative process optimizations are discussed. Current microbial product processing techniques are not suited for next generation probiotics, thus optimizations or entirely novel processing approaches are needed. Freeze-drying is currently the only method that keeps cells viable during processing and storage, but optimization of the process for individual strains is required, e.g. by adding antioxidants to the drying solution.Oral delivery of live next generation probiotics is poorly investigated. The strains in question are often known to colonize primarily in the colon, and carriers, such as microparticles and microdevices, which have been verified for colon-targeted delivery of drugs, may represent a novel choice as delivery vehicle for next generation probiotics. •Antioxidants increases viability of oxygen-sensitive microbes during freeze-drying.•Desiccation of oxygen-sensitive microbes is required for prolonged storage.•Freeze-drying is the best method for processing of oxygen-sensitive microbes.