Establishment of a Low-Cost and Efficient In Vitro Model for Cultivating Intestinal Microbiota

The Simulator of Human Intestinal Microbial Ecosystem (SHIME) has hindered widespread adoption due to its high cost. This study founded biomimetic multilink fermentation equipment (BMLFE), priced at half or even lower than SHIME. It was improved based on multilink fermentation equipment (MLFE) by modifying materials, peristaltic pumps, fermentation time, and dietary habits while calculating transfer time and volumes and conducted anaerobic fermentation for 15 days followed by monitoring changes in intestinal microbial composition and short-chain fatty acids (SCFAs). We observed that the intestinal microbiota achieved a stable state after the ninth day and retained the predominant bacterial species in the fecal inoculum. The Bacillota/Bacteroidota values of the descending colon (DC) were similar to those in the fecal samples. However, the stability of SCFAs was relatively delayed and reached stability only after the 11th day. Meanwhile, the concentration ratio of acetic acid, propionate, and butyric acid metabolized by transverse colon (TC) and DC on the 11-15th days was close to that in fecal inoculations. Therefore, BMLFE can be used to simulate the human gastrointestinal environment in vitro studies. It is expected to be employed in clinical FMT and may even contribute to establishing stable enterotypes through dietary intervention.