DOI: https://doi.org/10.55373/mjchem.v28i2.224

Keywords: Rhamnolipid biosurfactant, ultra-low interfacial tension, glycolipid characterization, diesel and kerosene biodegradation, microbial enhanced oil recovery

Abstract

The application of ultra-low interfacial tension (IFT) surfactants from chemically modified surfactants is common in the oil and gas field. Chemically modified surfactants, unfortunately, come with various limitations that require a reconsideration. In this research, a bacterial ultra-low interfacial tension (IFT) Rhamnolipid-biosurfactant, NR-Rhamno, produced by Pseudomonas aeruginosa NR.22 is introduced as a potential surfactant for the bioremediation of petroleum-based contaminants. The production was conducted using phosphate-limited proteose peptone-glucose-ammonium salt (PPAS) and two modified media containing 1.0% (v/v) diesel and kerosene, respectively. NR-Rhamno was characterized using biochemical and physico-chemical tests, which includes Fourier-transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), and Thermogravimetric Analysis (TGA). Foaming (41.13 ± 0.21%) indicated that NR-Rhamno is potentially suitable for the diesel and kerosene remediation. Ultra-low IFT of 0.004 mN/m was obtained after 90 min of contact time. NR-Rhamno was confirmed as a type of glycolipid, with two types of Rhamnose components. The molecules are connected to one or/and two molecules of hydroxy acid(s), containing glycosyl head groups with 2 Rhamnose moieties on the Rhamnoses; and having 2 fatty acid tails (both are β-hydroxy-fatty acids) with RhaRha_C10C10 components. The presented results indicate the possible application of NR-Rhamno in oil and gas technology and related EOR enhancement in future.