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The purification and characterization of lipopeptide biosurfactants produced by Bacillus sp. MI27 permits to identify two clusters of cyclic and linear surfactin isoforms. Aiming for a potential application in industrial biotechnology, we studied its potential washing capacity. The results show a good ability to wash oil stains, motor oil and mayonnaise evaluated by the determination of the % of stain removal and tissue bleaching indices after washing. Optimal washing capacities were unregistered for 300 and 400 mg/L at pH values ranging from 5 to 9 and temperatures ranging from 20 to 40°C. Using a 4-factor mixing design, we optimized a liquid formula composed only of BioS; silicate; carboxymethyl cellulose and calcium phosphate. The washing efficiency of the formula is of the order of 43.46% for petroleum and 49.10% for motor oil with a percentage reduction in surface tension of about 55.79% corresponding to 25.7 mN/m. HIGHLIGHTS Identification of cyclic and linear surfactin isoforms from Bacillus sp. MI27.; Optimal washing capacities for 300–400 mg/L at pH values 5–9 and temperatures 20–40 °C.; Mixture design for optimized liquid formula composed only of BioS, silicate, carboxymethyl cellulose and calcium phosphate.; The washing efficiency of the formula is 43.46% for petroleum and 49.10% for motor oil.; Surface tension value of 25.7 mN/m.;

The problem of antimicrobial resistance is becoming a daunting challenge for human society and healthcare systems around the world. Hence, there is a constant need to develop new antibiotics to fight resistant bacteria, among other important social and economic measures. In this regard, murepavadin is a cyclic antibacterial peptide in development. The synthesis of murepavadin was undertaken in order to optimize the preparative protocol and scale-up, in particular, the use of new activation reagents. In our hands, classical approaches using carbodiimide/hydroxybenzotriazole rendered low yields. The use of novel carbodiimide and reagents based on OxymaPure® and Oxy-B is discussed together with the proper use of chromatographic conditions for the adequate characterization of peptide crudes. Higher yields and purities were obtained. Finally, the antimicrobial activity of different synthetic batches was tested in three Pseudomonas aeruginosa strains, including highly resistant ones. All murepavadin batches yielded the same highly active MIC values and proved that the chiral integrity of the molecule was preserved throughout the whole synthetic procedure.