The human alimentary tract is the natural habitat for trillions of live microorganisms, which regulate health and disease states. A healthy gut microbiota (GM) is dispensable for enhancing immunity, prevention of microbial growth, body growth, obesity, cancer, diabetes and many other diseases. The equilibrium in GM's composition and the absence/presence of major species enable specific responses to be pivotal for the body’s function. There have been some limited studies on the effectiveness of chemical engineering in shaping the GM to get beneficial health effects. Nevertheless, these studies have considerable drawbacks because of variations in ethnicity, gender, or diet between participants/cohorts, limited sample numbers, and various sequencing techniques, which lead to significant variations in the findings among research. Furthermore, diet-host-microbiota interactions can modulate intestinal homeostasis per se. Also, the high sensitivity of microbiota to external stimuli, such as sampling procedure, and the physicochemical complexity of the gut environment make its in vitro culture is another challenging issue. New engineered devices have been shown to have the potential to model some important features of the intestinal structure, but they are usually unable to sustain culture of microbiota over an extended period of time.

As can be seen, microbiota investigation is a hot topic of research and its in vitro culture has gained high interest in different fields, yet there is a long way for meritorious application of chemical engineering in improving the body health through modulation of GM.

This Special Issue therefore welcomes original research articles, systematic and critical reviews, short communications, and scientific reports in the areas of chemical engineering and gut microbiota investigation.

Topics covered will include but are not restricted to:

· Basic and experimental studies on bacterial therapies for intestinal diseases based on chemical engineering.

· Application of machine learning techniques.

· Mechanistic papers.

· Application chemical engineering in of food sciences and fermentation technology.

· Microbiota transplantation.

· Targeting the neurotransmitters, metabolites, neurotoxins and contaminants of the gut microbiota.

· Nanoencapsulation and chemical engineering for probiotic/drug delivery.

· Methodological/mechanistic and commentary papers.

· Novel proposals to utilize/develop chemical engineering techniques to modulate gut microbiota.