Engineering the Autotroph Methanococcus maripaludis for Geraniol Production

Area of Science:

• Microbial biotechnology
• Synthetic biology
• Metabolic engineering

Background:

• Methanococcus maripaludis is a methanogenic archaeon known for rapid autotrophic growth on H2 and CO2.
• This organism presents potential as a microbial chassis for cost-effective biochemical production.
• Geraniol is a monoterpene with applications in fragrances and flavors.

Purpose of the Study:

• To engineer Methanococcus maripaludis for geraniol production.
• To evaluate geraniol yields under different growth conditions (autotrophic vs. heterotrophic).
• To identify strategies for enhancing geraniol biosynthesis via metabolic engineering.

Main Methods:

• Cloning a synthetic geraniol synthase (GES) gene from Ocimum basilicum into a M. maripaludis expression vector.
• Culturing recombinant M. maripaludis under autotrophic (H2/CO2 or formate) and heterotrophic conditions.
• Measuring geraniol production using puromycin selection and in its absence.

Main Results:

• Recombinant M. maripaludis produced geraniol at 2.8 mg/g dry weight (autotrophic H2/CO2) and 4.0 mg/g dry weight (autotrophic formate).
• Geraniol yield decreased 2-3 fold under heterotrophic growth conditions.
• Geraniol production increased to 4.6 mg/g dry weight in the absence of puromycin during autotrophic formate growth.

Conclusions:

• Methanococcus maripaludis can be engineered to produce geraniol via autotrophic biosynthesis.
• Optimizing growth conditions and metabolic pathways can enhance geraniol yields.
• This work supports the use of M. maripaludis as a sustainable platform for producing valuable chemicals.