Graphical abstract

Surfactants play a very important role in laundry and household cleaning products ingredients. In this research, the application of lipopeptide biosurfactants, produced by Bacillus subtilis SPB1, in the formulation of a washing powder was investigated. The SPB1 biosurfactant was mixed with sodium tripolyphosphate as a builder and sodium sulfate as filler. The efficiency of the formulated detergent composition with different washing conditions to remove a stain from cotton fabric was examined. The results showed that the formulated detergent was effective in oil removal, with optimal washing conditions of pH, temperature, striate and time of washing system of 7, 65°C, 1000 RPM and 60 min, respectively. A comparative study of different detergent compositions (biosurfactant-based detergent, combined biosurfactantcommercial detergent, and a commercial detergent) for the removal of oil and tea stains, proved that the bio-scouring was more effective (>75%) in terms of the stain removal than the commercial powders (<60%). Moreover, the results demonstrated that the biosurfactant acts additively with a commercial detergent and enhances their performance from 33 to 45% in removing oil stain and from 57 to 64% in removing tea stain. As a conclusion, in addition to the low toxicity and the high biodegradability of the microbial biosurfactants, the results of this study have shown that the future use of this lipopeptide biosurfactant as laundry detergent additive is highly promising.

Microbial surfactants are natural amphiphilic compounds with high surface activities and emulsifying properties. Due to their structural diversity, low toxicity, biodegradability, and chemical stability in different conditions, these molecules are potential substitutes for chemical surfactants; their interest has grown significantly over the last decade. The current study focuses on the isolation, identification, and characterization of a lactic acid bacteria that produces two forms of biosurfactants. The OL5 strain was isolated from green olive fermentation and identified using MALDI/TOF and ADNr16S amplification. Emulsification activity and surface tension measurements were used to estimate biosurfactant production. The two biosurfactants derived from L. plantarum OL5 presented good emulsification powers in the presence of various oils. They were also shown to have the potential to reduce water surface tension from 69 mN/m to 34 mN/m and 37 mN/m within a critical micelle concentration (CMC) of 7 mg/ml and 1.8 mg/ml, respectively, for cell bound and extracellular biosurfactants. Thin layer chromatography (TLC) and FT-IR were used to analyze the composition of the two biosurfactants produced. the obtained data revealed that the two biomolecules consist of a mixture of carbohydrates, lipids and proteins. We demonstrated that they are two anionic biosurfactants with glycolipopeptide nature which are stable in extreme conditions of temperature, pH and salinity.

Thanks to their multifunctional properties, such as foaming, emulsifying and skin hydrating activity, biosurfactants are potentially used in the cosmetic industry. In the present work, firstly, skin cream formulations using chemical surfactant agents and lipopeptide biosurfactants isolated from Bacillus subtilis SPB1 were investigated. The efficiency of the selected formula, containing 15% biosurfactant, was tested. Their physicochemical properties were satisfying. In fact, it shows a spreading ability of 23 mm, a water activity of 0.72 and a pH value of 5. In addition, their biological activities were interesting. As a result, it shows a zone of inhibition against Gram-positive bacteria ranging from 8 to 15 mm. Moreover, it presents an antiradical effect against diphenyl-1-picrylhydrazyl (DPPH) with an IC50 of the order of 68 mg/mL. Second, seeking a highly stable SPB1 biosurfactant formulation for an easy commercial trend, a combination of biosurfactant, Gum Arabic (GA) and glycerol was optimized using the Box–Behnken (BB) design. As analysed, the model predicts an optimal value of the surface tension (ST) equal to 40.18 ± 0.39 mN/m when the respective values of the percentages of SPB1 BioS, glycerol and GA are equal to 72.62, 7.5 and 1.5%. Under these conditions, the emulsification index (EI)-24% is of the order of 81.76 ± 0.14%.