Editing Metabolic engineering (section)

===Setting up a metabolic pathway for analysis===
The first step in the process is to identify a desired goal to achieve through the improvement or modification of an organism's metabolism.  Reference books and online databases are used to research reactions and metabolic pathways that are able to produce this product or result. These databases contain copious genomic and chemical information including pathways for metabolism and other cellular processes.  Using this research, an organism is chosen that will be used to create the desired product or result. Considerations that are taken into account when making this decision are how close the organism's metabolic pathway is to the desired pathway, the maintenance costs associated with the organism, and how easy it is to modify the pathway of the organism.  ''Escherichia coli'' (''E. coli'') is widely used in metabolic engineering to synthesize a wide variety of products such as amino acids because it is relatively easy to maintain and modify.<ref>University of California - Los Angeles (2008, December 18). "Genetic Modification Turns E. Coli Bacteria Into High Density Biofuel". ''ScienceDaily.'' Retrieved December 7, 2011, from https://www.sciencedaily.com/releases/2008/12/081218151652.htm</ref>  If the organism does not contain the complete pathway for the desired product or result, then genes that produce the missing enzymes must be incorporated into the organism.