Microbial strain improvement is used in areas such as pharmaceutical and chemical production, whole-cell biocatalysis and bioremediation. Strain improvement can be achieved using metabolic engineering and synthetic biology approaches.
Metabolic engineering is the application of engineering principles to the metabolic pathways to achieve a particular goal. Metabolic engineering is an approach used to improve the productivity of microbial strains to generate products such as antibiotics, biosynthetic precursors and polymers.
In bioprocessing of chemicals and fuels, chemical stress often occurs. Metabolites, substrates and substrate impurities may be toxic to cells by damaging biological molecules, organelles, membranes or disrupting biological processes. In order to maximize the use of microbes for production of chemicals, whole-cell biocatalysis and bioremediation there is a need to develop strains that are tolerant to these stresses.
Microorganisms can be used to produce biofuels but these biofuels can be toxic to the cells. Many biofuels have been found to damage the cell membrane and interfere with physiological processes. This results in a trade off for the cells between biofuel production and survival which reduces potential yields. Strategies in engineering strains for biofuel tolerance include engineering biofuel export systems, heat shock proteins, membrane modifications and general stress responses.