Figure 2

![Figure 2: Summary of metabolic engineering strategies applied to improve microbial 5-HTP production, including directed enzyme evolution, cofactor supply enhancement, and precursor pathway optimization. Progressive improvements in titer and yield across different approaches are compared.](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901931/bin/fbioe-09-624503-g0002.jpg)

> Source: Xin-Xin Liu et al. "Advances in the Microbial Synthesis of 5-Hydroxytryptophan.." *Frontiers in bioengineering and biotechnology*, 2021. PMID: [33634088](https://pubmed.ncbi.nlm.nih.gov/33634088/)

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  <img src="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7901931/bin/fbioe-09-624503-g0002.jpg" alt="Summary of metabolic engineering strategies applied to improve microbial 5-HTP production, including directed enzyme evolution, cofactor supply enhancement, and precursor pathway optimization. Progressive improvements in titer and yield across different approaches are compared." />
  <figcaption>Figure 2. Summary of metabolic engineering strategies applied to improve microbial 5-HTP production, including directed enzyme evolution, cofactor supply enhancement, and precursor pathway optimization. Progressive improvements in titer and yield across different approaches are compared.<br>  Source: Xin-Xin Liu et al. "Advances in the Microbial Synthesis of 5-Hydroxytryptophan.." <em>Frontiers in bioengineering and biotechnology</em>, 2021. PMID: <a href="https://pubmed.ncbi.nlm.nih.gov/33634088/">33634088</a></figcaption>
</figure>