Net-zero Photosynthetic Biorefinery for Selective Biosurfactant and Bioemulsifier Valorization

Surfactants are ubiquitous in modern industrial applications, ranging from personal care products and household cleaners to agriculture and oil recovery. However, over 60% of commercial surfactants are derived from petrochemical sources, contributing to environmental toxicity, poor biodegradability in aquatic living beings, leading to long-term harm to ecosystems. Moreover, the increasing global demand for eco-friendly surfactants, coupled with the urgent need to reduce reliance on fossil-derived chemicals, has spurred interest in bio-based alternatives. Microalgae, as photosynthetic microorganisms, present a promising green alternative for sustainable bio-surfactant production due to its high lipid content and ability to thrive in diverse environments. In this respect, the present proposal NEXUS-BIO aims to demonstrate an integrated approach to producing bio-surfactants from algal biomass, combining cultivation optimization, green extraction methods, and biosurfactant synthesis to achieve a circular bioeconomy model. However, the low economic performance due to higher production cost are the main voids in scaling up this technology for real-life applications. To overcome productivity and processing barriers, NEXUS-BIO will combine three innovations: (i) strain optimization of freshwater algae with high lipid and biosurfactant content; (ii) quorum-sensing (QS) modulation using signal molecules to trigger biosynthetic pathways and natural flocculation, boosting yield and easing harvesting; and (iii) low-energy downstream processing to recover biosurfactant at industrial purity. These strategies in a CO2-driven algal biorefinery aim to achieve the viable yield of biosurfactant in a selected strain of 2.5–5.0 g/L, paving the way for industrial deployment. Therefore, the development of a closed-loop biorefinery concept integrating algae for biosurfactant production with valorization of biomass into high-value bioproducts, aiming for a net-negative carbon footprint.