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Agarose-Based Model Ecosystem for Cultivating Methanotrophs in a Methane-Oxygen Counter Gradient
Published on: September 6, 2024
An engineered methanogenic pathway derived from the domains Bacteria and Archaea
Daniel J Lessner1, Lexan Lhu, Christopher S Wahal
1Department of Biochemistry and Molecular Biology, the Pennsylvania State University, University Park, Pennsylvania, USA. dlessner@uark.edu
Mbio
|November 10, 2010
Summary
Engineered Methanosarcina acetivorans efficiently metabolizes methyl acetate and methyl propionate using a novel esterase, demonstrating robust growth and methane production. This advancement offers a new pathway for utilizing ester compounds in biotechnological applications.
Area of Science:
- Microbial Biotechnology
- Synthetic Biology
- Biochemistry
Background:
- Methanosarcina acetivorans is a model archaeon for studying methanogenesis.
- Esterase enzymes are crucial for breaking down ester compounds.
- Limited understanding exists regarding the metabolic capabilities of M. acetivorans with specific ester substrates.
Purpose of the Study:
- To engineer a strain of Methanosarcina acetivorans for enhanced esterase activity.
- To investigate the utilization of methyl acetate and methyl propionate as sole carbon and energy sources by the engineered strain.
- To characterize the metabolic fate of these ester substrates and their byproducts.
Main Methods:
- Construction of a plasmid-based expression system in M. acetivorans.
- Fusion of the mekB gene encoding a broad-specificity esterase from Pseudomonas veronii to a constitutive M. acetivorans promoter.
- Cultivation of the engineered strain using methyl acetate and methyl propionate as substrates.
- Measurement of esterase activity, substrate consumption, methane formation, and byproduct accumulation.
Main Results:
- The engineered M. acetivorans strain exhibited an 80-fold increase in esterase activity compared to the wild-type.
- Robust growth and significant methane production were observed with >97% consumption of methyl acetate and methyl propionate.
- Methanol was undetectable when using methyl acetate, with acetate accumulation, indicating methanol as the preferred substrate.
- Acetate was subsequently consumed, supporting continued growth after adaptation, while propionate remained unmetabolized.
Conclusions:
- Expression of Pseudomonas veronii esterase (MekB) in M. acetivorans significantly enhances its ability to metabolize ester compounds.
- Engineered M. acetivorans can efficiently utilize methyl acetate and methyl propionate for growth and methane production.
- The study provides insights into substrate preference and metabolic pathways within engineered methanogens for potential biotechnological applications.
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