Isoprene Production from Municipal Wastewater Biosolids by Engineered Archaeon <i>Methanosarcina acetivorans</i>

Wastewater biosolids are a promising feedstock for production of value-added renewable chemicals. Methane-producing archaea (methanogens) are already used to produce renewable biogas via the anaerobic treatment of wastewater. The ability of methanogens to efficiently convert dissolved organic carbon...

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Bibliographic Details
Main Authors: Sean Carr, Jared Aldridge, Nicole R. Buan
Format: Article
Language:English
Published: MDPI AG 2021-04-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/11/8/3342
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Summary:Wastewater biosolids are a promising feedstock for production of value-added renewable chemicals. Methane-producing archaea (methanogens) are already used to produce renewable biogas via the anaerobic treatment of wastewater. The ability of methanogens to efficiently convert dissolved organic carbon into methane makes them an appealing potential platform for biorefining using metabolic engineering. We have engineered a strain of the methanogen <i>Methanosarcina acetivorans</i> to produce the volatile hemiterpene isoprene in addition to methane. The engineered strain was adapted to grow in municipal wastewater through cultivation in a synthetic wastewater medium. When introduced to municipal wastewater the engineered methanogens were able to compete with the indigenous microorganisms and produce 0.97 mM of isoprene (65.9 ± 21.3 g per m<sup>3</sup> of effluent). The production of isoprene in wastewater appears to be dependent on the quantity of available methanogenic substrate produced during upstream digestion by heterotrophic fermenters. This shows that with minimal adaptation it is possible to drop-in engineered methanogens to existing wastewater environments and attain value-added products in addition to the processing of wastewater. This shows the potential for utilizing methanogens as a platform for low-cost production of renewable materials without expensive feedstocks or the need to build or adapt existing facilities.
ISSN:2076-3417