Strain evolution and novel downstream processing with integrated catalysis enable highly efficient coproduction of 1,3-propanediol and organic acid esters from crude glycerol

Bioconversion of natural microorganisms generally results in a mixture of various compounds. Downstream processing (DSP) which only targets a single product often lacks economic competitiveness due to incomplete use of raw material and high cost of waste treatment for by-products. Here, we show with the efficient microbial conversion of crude glycerol by an artificially evolved strain and how a catalytic conversion strategy can improve the total products yield and process economy of the DSP. Specifically, Clostridium pasteurianum was first adapted to increased concentration of crude glycerol in a novel automatic laboratory evolution system. At m3 scale bioreactor the strain achieved a simultaneous production of 1,3-propanediol (PDO), acetic and butyric acids at 81.21, 18.72, and 11.09 g/L within only 19 h, respectively, representing the most efficient fermentation of crude glycerol to targeted products. A heterogeneous catalytic step was developed and integrated into the DSP process to obtain high-value methyl esters from acetic and butyric acids at high yields. The coproduction of the esters also greatly simplified the recovery of PDO. For example, a cosmetic grade PDO (96% PDO) was easily obtained by a simple single-stage distillation process (with an overall yield more than 77%). This integrated approach provides an industrially attractive route for the simultaneous production of three appealing products from the crude glycerol fermentation broth, which greatly improve the process economy and ecology.

Subjects

1,3-propanediol

automatic adaptive evolution

Clostridium pasteurianum

coproduction

organic acid esters

DDC Class

600: Technik

Funding(s)

Projekt DEAL

Publication version

publishedVersion

Lizenz

https://creativecommons.org/licenses/by-nc/4.0/

Name

Biotech Bioengineering - 2022 - Zhang - Strain evolution and novel downstream processing with integrated catalysis enable.pdf

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2.39 MB

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Adobe PDF

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Strain evolution and novel downstream processing with integrated catalysis enable highly efficient coproduction of 1,3-propanediol and organic acid esters from crude glycerol