The present study focused on producing and characterizing a type of biosurfactant (BS) derived from lactic acid bacteria (LAB) and its potential applications in pharmaceutical and food industries due to the preference of employing nonpathogenic organisms in bioprocesses. To this aim, several screening approaches were applied to identify an efficient BS-producing strain from a set of LAB, and Pediococcus dextrinicus SHU1593 was selected as the most operative one. The BS produced by P. dextrinicus was isolated and structurally characterized as a lipoprotein with an approximately equal ratio of lipids (~52% (w/w)) and proteins (47% (w/w)). It reduced the surface tension (ST) of phosphate-buffered saline (PBS) from 72.80 ± 0.10 to 39.01 ± 0.32 mN/m. The results also indicated the potential of developing low-cost strategies aimed at the production of efficient LAB-derived BSs which are structurally and quantitatively similar to the ones obtained from conventional media. Finally, given the physical and functional characterization (i.e. critical micelle concentration (CMC), emulsification index (%E 24 ), stability, as well as antimicrobial and anti-adhesive activities) of the BS produced in the present study, it can be introduced as a promising candidate to be employed in plenty of areas in pharmaceutical and food industries.

Novel strategies toward the use of low-cost media to produce food-grade microbial products have been considerably attended in recent years. In this study, date syrup obtained from low-quality date fruits was implemented for biosurfactant production by the probiotic bacterium, PTCC 1637. The most level of biosurfactant was achieved through fermentation in a bioreactor with a lactose feeding phase, up to 24 h. Critical micelle concentration of the cell-bound biosurfactant was found to be 6.0 mg/ml with a minimum surface tension value of 39.00 mN/m and a maximum emulsifying index of 42%. The spectrum of Fourier transform infrared spectroscopy taken from the cell-bound biosurfactant suggests that it should be a multi-component mixture of protein and polysaccharides associated with phosphate groups. The results indicated the potential for developing strategies toward the low-cost production of food-grade biomaterials by probiotic microorganisms.

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In this Article, the legend of Figure 5 is incorrect: "Stability study of BS derived from P. dextrinicus SHU1593 at different pH values. Results are expressed as mean ± standard deviations of values from triplicate experiments. " should read: "Stability study of BS derived from P. dextrinicus SHU1593 at different pH values. Results are expressed as mean ± standard deviations of values from triplicate experiments. " Additionally, this Article contains a typographical error in the Author Contributions section.