Membrane Permeability of Terpenoids Explored with Molecular Simulation

Area of Science:

• Biotechnology
• Chemical Engineering
• Molecular Biology

Background:

• Terpenoids have broad industrial applications but are scarce in plants.
• Microbial hosts offer a sustainable alternative for terpenoid production.
• Nondestructive product recovery using hydrophobic overlays is crucial for cost-effectiveness.

Purpose of the Study:

• To investigate if oxidizing terpenoids enhances their membrane permeability and extraction from microbial hosts.
• To compare the extraction efficiency of oxidized versus conventional terpenoids.
• To assess the impact of terpenoid oxidation on microbial host tolerance and growth.

Main Methods:

• Molecular dynamics simulations were used to compute membrane permeabilities of terpenoids and their oxidized forms.
• Extraction efficiency was evaluated under conditions simulating industrial bioreactors (close contact) and aqueous extraction.
• Experimental toxicity assays were conducted on microbial hosts exposed to various terpenoids.

Main Results:

• Terpenoid membrane permeability and extraction efficiency are independent of oxidation when using hydrophobic overlays in close contact.
• Oxidation accelerates extraction only in aqueous systems, which are less industrially relevant.
• While most terpenoids were tolerated, oxidized forms showed increased toxicity to microbial hosts, hindering growth.

Conclusions:

• Terpenoid oxidation does not offer significant advantages for extraction productivity in industrial biorefineries using hydrophobic overlays.
• The previously observed benefits of oxidation for fatty acyl product recovery do not directly translate to terpenoids.
• Further research may focus on alternative strategies to enhance terpenoid recovery or mitigate toxicity.