Bio-cleaning Efficiency of Rhamnolipids Produced from Native Pseudomonas aeruginosa Grown on Agro-industrial By-products for Liquid Detergent Formulation

Abstract

The cleaning activity of surface-active agents such as rhamnolipids (RLs) requires utmost effectiveness and is employed abundantly in various industries, particularly laundry cleaning, detergents, and cosmetics. In the current study, RLs were produced from Pseudomonas aeruginosa isolated from oil-contaminated soil using a minimal medium amended with agro-industrial by-products of refinery vegetable oil wastes (comprising of unsaturated types of fatty acids as determined by GC analysis) and dairy whey. The results showed that an amount of 5.72 g/L of RLs were obtained, while lower concentrations were obtained using chemically defined carbon sources. Ten congeners of mono- and di-RLs were detected by LC-MS, and they reduced the surface tension of water to 26 mN/m with a critical micelle concentration of 33 mg/L. Furthermore, the produced RLs showed promising cleaning and detergency properties in the removal of different stains on tested fabrics with a Stain Removal Index (SRI) of 17.45%. Moreover, an efficient cleaning was obtained when RLs were applied to a liquid detergent formulation model, and a cleaning power (∆E) of 245.95 and SRI of 36.28% were achieved. The present work showed that the produced RLs could be exploited as a powerful and alternative eco-friendly cleaning agent in many industries.