The membrane lipids of archaea differ from those of bacteria and eukarya in backbone stereochemical configuration, chemical linkage type, and hydrophobic chain structure, a fundamental dichotomy termed the lipid divide. Synthetic biology and metabolic engineering have enabled reconstruction of archaeal lipid biosynthesis pathways in bacterial and eukaryotic hosts, yielding production levels reaching 30% of membrane phospholipids in Escherichia coli and 6.5% of total cellular lipids in Saccharomyces cerevisiae. These achievements required coordinated expression of core archaeal enzymes combined with enhanced isoprenoid precursor supply. A recurring finding is that bacterial and eukaryotic enzymes exhibit remarkable substrate promiscuity toward archaeal lipid precursors, enabling biosynthesis of archaetidylglycerol, archaetidylethanolamine, and archaetidylinositol without requiring archaeal enzymes. This review examines the biosynthetic pathways, host systems, and engineering strategies underlying these advances. We consider how heterologous reconstitution informs longstanding questions about membrane evolution and the nature of the last universal common ancestor. Engineered strains with hybrid archaeal-bacterial membranes not only remain viable but also exhibit enhanced stress tolerance, demonstrating that the lipid divide does not preclude membrane coexistence while enabling biotechnological applications from stress-tolerant cell factories to archaeosome-based delivery systems.
Li et al. (Wed,) studied this question.