Engineering growth independent production: programmable control loops for high-titer rhamnolipids for improved green surfactant sustainability.

Rhamnolipid biosurfactants have garnered significant attention as renewable, biodegradable alternatives to conventional, petroleum-derived surfactants, aligning closely with global sustainable development goals. Nevertheless, their commercial viability remains hampered by intrinsic production challenges mainly suboptimal production titers, expensive downstream recovery, and biosafety constraints of native producers. This review synthesizes current advances within an integrated framework that couples metabolic pathway optimization with strategies to enhance titer, rate, and yield (TRY), high-cell-density cultivation, and cost-effective downstream processing. Key innovations in pathway engineering such as elimination of competing routes and cofactor rebalancing are examined alongside dynamic regulatory systems that decouple growth from product formation. Process intensification techniques, including in situ foam control and membrane-based separations, are evaluated for their impact on purification efficiency and overall process economics. Critical research gaps and limitations are identified, with recommendations for future efforts to bridge metabolic landscape and scale-up implementation. Finally, potential market-ready rhamnolipid formulations are discussed, illustrating their application spectrum from agriculture and personal care to environmental remediation and healthcare. By contextualizing synthetic biology breakthroughs within rigorous techno-economic and life-cycle assessments, this review maps a clear trajectory toward the industrial deployment of truly sustainable glycolipid biosurfactants.