The so-called bioengineering is generally believed to be based on the theory and technology of biology (especially molecular biology, microbiology, genetics, biochemistry and cytology), combined with modern engineering technologies such as chemical engineering, machinery, and electronic computer, fully utilize the latest achievements of molecular biology, consciously manipulate genetic material, directionally transform biology or its functions, and create new species with ultra distant properties in a short period of time, This kind of "engineering bacteria" or "engineering cell lines" can be cultured on a large scale through appropriate bioreactors to produce a large number of useful metabolites or play their unique physiological functions.