Yields can be improved in bacterial product synthesis using several strategies.
Mutating the genome of the bacteria is one method, producing a library of mutants that can then be assayed (using a high-throughput technique) to determine which mutants have elevated synthesis levels. Genome sequencing could then be used to determine what mutations have occurred, if irradiation is used. Specific approaches, such as Crispr-Cas9 or synthetic genomes are both options as well, allowing targeted mutations to be inserted into the bacterial genome.
Metabolic engineering involves modifying the entire metabolic pathway to increase the flux through it. This approach, heavily relying on synthetic biology, requires a good understanding of the genome of the bacteria being used.
The relative expression levels of the necessary biosynthetic enzymes can be increased, while other enzymes at branchpoints in the pathway can be suppressed – this increases the flux down the desired pathway.
Co-factors and energy may also be the limiting factor in product synthesis. Metabolic engineering could be used to increase the synthesis of these.
The concentration of the product in the bacteria may become toxic. Efflux pumps could be added, transporting the product to the growth media. Continuous fermentation could be used to maintain a specific concentration of product in the growth media.
Optimising the fermentation conditions can also increase the synthesis of a product by bacteria. Ensuring the correct temperature and growth media is used will help ensure the maximal growth rate is obtained. However, some bacteria are complicated to grow (fastidious) – it may be necessary to make compromises here to have obtainable conditions for the fermentation.