E. coli

Since 1961, scientists proposed the idea of genetic circuits used for computational tasks. Collaboration between biologists and computing scientists has allowed designing digital logic gates on the metabolism of E. coli. As Lac operon is a two-stage process, genetic regulation in the bacteria is used to realize computing functions. The process is controlled at the transcription stage of DNA into messenger RNA. Studies are being performed attempting to program E. coli to solve complicated mathematics problems, such as the Hamiltonian path problem. A computer to control protein production of E. coli within yeast cells has been developed. A method has also been developed to use bacteria to behave as an LCD screen. In July 2017, separate experiments with E. coli published on Nature showed the potential of using living cells for computing tasks and storing information. A team formed with collaborators of the Biodesign Institute at Arizona State University and Harvard's Wyss Institute for Biologically Inspired Engineering developed a biological computer inside E. coli that responded to a dozen inputs. The team called the computer "ribocomputer", as it was composed of ribonucleic acid. Meanwhile, Harvard researchers probed that is possible to store information in bacteria after successfully archiving images and movies in the DNA of living E. coli cells. …

Due to the low cost and speed with which it can be grown and modified in laboratory settings, E. coli is a popular expression platform for the production of recombinant proteins used in therapeutics. One advantage to using E. coli over another expression platform is that E. coli naturally does not export many proteins into the periplasm, making it easier to recover a protein of interest without cross-contamination. The E. coli K-12 strains and their derivatives (DH1, DH5α, MG1655, RV308 and W3110) are the strains most widely used by the biotechnology industry. Nonpathogenic E. coli strain Nissle 1917 (EcN), (Mutaflor) and E. coli O83:K24:H31 (Colinfant)) are used as probiotic agents in medicine, mainly for the treatment of various gastrointestinal diseases, including inflammatory bowel disease. It is thought that the EcN strain might impede the growth of opportunistic pathogens, including Salmonella and other coliform enteropathogens, through the production of microcin proteins the production of siderophores.

Optimum growth of E. coli occurs at 37 °C (99 °F), but some laboratory strains can multiply at temperatures up to 49 °C (120 °F). E. coli grows in a variety of defined laboratory media, such as lysogeny broth, or any medium that contains glucose, ammonium phosphate monobasic, sodium chloride, magnesium sulfate, potassium phosphate dibasic, and water. Growth can be driven by aerobic or anaerobic respiration, using a large variety of redox pairs, including the oxidation of pyruvic acid, formic acid, hydrogen, and amino acids, and the reduction of substrates such as oxygen, nitrate, fumarate, dimethyl sulfoxide, and trimethylamine N-oxide. E. coli is classified as a facultative anaerobe. It uses oxygen when it is present and available. It can, however, continue to grow in the absence of oxygen using fermentation or anaerobic respiration. Respiration type is managed in part by the arc system. The ability to continue growing in the absence of oxygen is an advantage to bacteria because their survival is increased in environments where water predominates.