Antimicrobial potential of sophorolipids for anti-acne, anti-dental caries, hide preservation and food safety applications

Authors: Ashby, Richard - Rick; Solaiman, Daniel; Fan, Xuetong; Olanya, Modesto

Submitted to: ACS Symposium Series
Publication Type: Book / Chapter
Publication Acceptance Date: 4/2/2018
Publication Date: 9/4/2018
Citation: Ashby, R.D., Solaiman, D., Fan, X., Olanya, O.M. 2018. Antimicrobial potential of sophorolipids for anti-acne, anti-dental caries, hide preservation and food safety applications. In: Fan, X., Ngo, H., and Wu, C. (eds). Natural and Bio-based Antimicrobials for Food Application. ACS Symposium Series. 1287:193-208. https://doi.org/10.1021/bk-2018-1287.ch010.
DOI: https://doi.org/10.1021/bk-2018-1287.ch010

Interpretive Summary: Many current methods of regulating bacterial growth are becoming problematic due to increased concerns over chemical usage and increased bacterial resistance to commonly-used antibiotics. In an effort to provide new, biorenewable alternatives to the present antimicrobial technologies, novel approaches have been studied that eliminate many of the present fears. Sophorolipids are naturally-produced molecules that are typically derived from harmless yeasts. They are most notably applied as natural components in detergent and/or cleaning products but have also been documented to possess properties that can be beneficial for bacterial control. This chapter describes some of our efforts to use sophorolipids to control the causative bacteria involved in acne and cavity (dental caries) formation, leather preservation and food safety. While specific bacterial strains react differently to sophorolipid applications, results show that sophorolipids at sufficient doses and exposure-times are effective in retarding bacterial growth and may be potential alternatives to the currently-used practices of bacterial control in many different applications.

Technical Abstract: Sophorolipids (SLs) are microbial glycolipids that can be produced via fermentation in relatively large yields (reportedly as high as 400 g/L under appropriate growth conditions). These versatile molecules have demonstrated usefulness as additives in detergent, cleaner, cosmetic, and stabilizer applications. In addition, SLs have been documented to possess antimicrobial properties, particularly against Gram-positive (Gram+), but also, to a lesser extent, against Gram-negative (Gram-) bacterial strains. The focus of this chapter is on the antimicrobial effects of SLs against the acne-causing bacterial strain (Propionibacterium acnes, Gram+), the dental caries-causing Streptococci (Gram+) and Lactobacilli (Gram+), many common Gram+ and Gram- bacterial strains associated with hide preservation (important for the leather industry), and three pathogenic bacteria associated with food (Salmonella enterica, Gram-; Escherichia coli O157:H7, Gram-; and Listeria monocytogenes, Gram+). This chapter reviews the relative effectiveness of lactonic vs open-chain SL molecules in antimicrobial applications and describes the time- and concentration-dependent, and strain-specific effectiveness of SLs against the above-mentioned bacterial strains.