Consistent biosynthesis of D-glycerate from variable mixed substrates
Name
Consistent biosynthesis v2 (1).pdf
Description
Accepted version
Size
1.18 MB
Format
Adobe PDF
Checksum (MD5)
129f652d7f39910b400ae8b3851f68b3
Author(s)
Ni, Cynthia
Prather, Kristala LJ
Date Issued
January 5, 2024
Journal
Metabolic Engineering
Publisher
Elsevier BV
Version
Author's final manuscript
Abstract
The use of waste streams and other renewable feedstocks in microbial biosynthesis has long been a goal for metabolic engineers. Microbes can utilize the substrate mixtures found in waste streams, though they are more technically challenging to convert to useful products compared to the single substrates of standard practice. It is difficult to achieve consistent biosynthesis in the face of the temporally changing nature of waste streams. Furthermore, the expression of all the enzymes necessary to convert mixed substrates into a product likely presents significant metabolic burden, which already plagues processes that utilize a single substrate. We developed an approach to utilize mixed feedstocks for production by activating expression of each biosynthetic pathway in the presence of its substrate. This expression control was used for two novel pathways that converted two substrates, galacturonate and gluconate, into a single product, D-glycerate. A production strain harboring both pathway plasmids produced 1.8 ± 0.3 and 1.64 ± 0.09 g L−1 of D-glycerate from galacturonate and gluconate alone, respectively. Fermentations that were fed a mixture of the two substrates, at different ratios, resulted in product titers between 1.48 ± 0.03 and 1.8 ± 0.1 g L−1. All fermentations were fed a total of 10 g L−1 substrate and there was no statistically significant difference in D-glycerate titer from the single or mixed substrate fermentations. We thus demonstrated consistent D-glycerate biosynthesis from single and mixed substrates as an example of robust conversion of complex feedstocks.
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Creative Commons Attribution-NonCommercial-NoDerivatives
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DOI of Published Version
https://doi.org/10.1016/j.ymben.2024.01.001
