The present invention relates to an in-vitro model of thehuman gut microbiome, the model comprising a culture of the gut microbiome, wherein the model has a cumulative enzymatic coverage of more than 85% of the gut microbiome of a healthy human. The model facilitates metabolic modeling and enables a better understanding of the structure and function of the human gut microbiome as well as of modifications of xenobiotics by intrinsic gut microbiota, such as biotransformation and bioaccumulation. It can further be used to study the effects of variations in nutritional conditions. Importantly, the invention can also be used for diagnosing a disease, such as a gastrointestinal disorder,a proliferative disease, a metabolic disorder, a cardiovascular disease, an immunological disease, and an infectious disease.