Myristic Acid Derived Sophorolipid: Efficient Synthesis and Enhanced Antibacterial Activity

Abstract

Microbial glycolipids are one of the most interesting alternatives to chemical-based surfactants as they exhibit improved biodegradability and less toxicity. However, their potential has been limited because of specificity of the yeast toward fatty acids having a carbon 16 or carbon 18 chain. This study focuses on sophorolipid (SL) production by the yeast Starmerella bombicola using myristic acid, a medium-chain carbon-14 fatty acid that has not been used as a substrate for SL production. The production was optimized for inoculum size and lipophilic substrate concentration. Furthermore, we also studied the effect of medium-chain fatty acid on yeast cell growth and optimized the process for excellent yield. The myristic acid SL (MASL) so synthesized consisted of mono- and diacetylated forms with preferential glycosylation at the methyl end group, as determined by high-resolution mass spectrometry. Individual congeners of the crude mixture were separated using dry column chromatography and then structurally characterized by mass spectrometry. The synthesized MASL was also shown to have promising surface tension, lowering abilities with a low CMC of 14 mg/L. The SL derived from myristic acid exhibited superior antibacterial activity as compared to SL derived from oleic acid. MASL was also found to be more potent against Gram-positive organisms as compared to Gram-negative organisms. This work, therefore, demonstrates successful synthesis of myristic acid-derived SL and its superior antibacterial activity, establishing a promising future for this biosurfactant.

Development of a multifunctional and self-preserving cosmetic formulation using sophorolipids and palmarosa essential oil against acne-causing bacteria

“…FORMULATION AGAINST ACNE-CAUSING BACTERIA observed after 15 min (Abhyankar, et al, 2021). The difference between MIC values found by authors could be explained by a variety of chemical constituents of sophorolipids.…”

“…The survival of S. aureus dropped to 3% with a concentration of 150 μg/ml of sophorolipids with an exposure time of 30 min. Using concentration above 350 μg/ml, the complete inhibition of the bacteria was observed after 15 min (Abhyankar, et al, 2021). The difference between MIC values found by authors could be explained by a variety of chemical constituents of sophorolipids.…”

Sophorolipids—Bio-Based Antimicrobial Formulating Agents for Applications in Food and Health

“…Oil-derived sophorolipids, which are natural products, could be used to replace synthetic surfactant detergent formulations as they were reported to display antibacterial activity against S. aureus [ 81 ]. Abhyankar et al [ 105 ] also studied the antibacterial activity exhibited by myristic acid derived sophorolipid against both Gram-positive and Gram-negative organisms [ 105 ].…”

Amide Modification of Glycolipid Biosurfactants as Promising Biocompatible Antibacterial Agents

“…16 Notably, this biological activity is less potent compared with traditional chemical antimicrobial agents, especially against Gram-negative bacteria and fungi. 12,17,18 Chemical modifications of fermentative SLs have been developed to improve the biological activity of SLs. 19 This process is known as semisynthesis and has been an important tool in the discovery and manufacture of antibiotics.…”