Rhamnolipids_GC-MS Analysis of the Fatty Acids

Oil exploration and production are increasingly shifting to deeper offshore environments, where accidental hydrocarbon releases pose a significant threat. Subsea oil spills like the Deepwater Horizon demonstrated the large-scale application of chemical dispersants, including subsea injection, as a primary response measure. However, uncertainties remain regarding dispersants’ performance and environmental implications under deep-sea conditions. This has prompted interest in alternative biologically derived surface-active agents that may combine dispersive action with enhanced biodegradation potential and reduced environmental impact. Exploring the biotechnological potential of indigenous deep-sea marine microorganisms in particular, is crucial for identifying unique biosurfactants as an alternative to chemical dispersants. In this context, we investigated the capacity of a deep-sea microbial consortium from 1,000 m depth in the Eastern Mediterranean, an emerging area of deep-sea hydrocarbon exploration and exploitation, to produce biosurfactants under simulated in situ conditions (100 bar, 14 °C), with crude oil (0.5% v/v) as the sole carbon source and nutrient amendments. Biosurfactant activity was detected during incubation, and glycolipid-type biosurfactants were isolated from the culture medium. Following purification by silica gel chromatography, a total rhamnolipid yield was 41.3 mg L⁻¹ (~10 mg g⁻¹ oil). Rhamnolipids were separated into mono- and di-rhamnolipid fractions and characterized for their functional groups (FTIR) and fatty acyl composition (GC–MS). FTIR confirmed the glycolipid nature of the extracts, while GC–MS revealed β-hydroxy fatty acids ranging from C6:0 to C18:0, demonstrating that deep-sea consortia can synthesize structurally diverse rhamnolipids under in situ conditions and supporting their operational relevance for subsea spill response. Our findings highlight biosurfactants as viable, environmentally aligned candidates for integration into future oil spill response strategies.