Designing an in-vitro gas profiling system for human faecal samples

There is an increasing recognition that the gas constituents of the colon, which are mainly the metabolic by-products of the colonic microbiota, are associated with the pathogenesis of colonic diseases and can be modulated by drugs or diet. Therefore, a real-time faecal gas profiler can generate invaluable information in the study of colonic disorders and their modulation. Unfortunately, most of the currently available intestinal gas profiling methods are either unreliable, cost-ineffective, rely on off-line measurement equipment which are bulky and expensive. Here, we developed a portable and low-cost in-vitro fecal fermentation system with array of gas and pressure sensors. The system is kept at a constant pressure using a commercial release valve unit. We are able to measure the in-vitro fecal gas production levels in real time and assess the kinetics in the presence of a highly-fermentable fiber as the feeding substrate while the headspace gas mixture was altered to mimic the colon environment. Through the representative measurements, intestinal gas production and bacterial metabolic activities can be assessed in a simulated colon gas environment with/without added substrates. This suggests that the system has potential as a practical research and diagnostic instrument for colonic disorders.