Posted by The growing demand for sustainable, biodegradable surfactants has pushed microbial biosurfactants—especially lipopeptides such as lichenysin—into the spotlight. Yet their industrial production remains challenging, largely because these molecules may inhibit the bacteria that produce them. A recent study by Sakiyo and Németh (2025) offers a compelling and innovative solution: using cyclodextrins (CDs) to “trap” biosurfactants during fermentation, reducing toxicity and increasing yield.
This study tested three natural CDs (α‑, β‑, γ‑CD) and one derivative (dimethyl‑β‑cyclodextrin, DIMEB) to see whether they could bind lichenysin during fermentation and thereby relieve product inhibition.
A two‑stage analysis was conducted: small‑scale kinetic experiments to measure growth rates, followed by 150 mL flask fermentations to quantify biomass, glucose consumption, surface tension reduction, and final biosurfactant yield. The results were surprisingly different for tyhe CDs studied. β‑CD behaved almost neutrally, while γ‑CD consistently inhibited both growth and product formation—likely due to its larger cavity size, which may sequester signaling peptides essential for B. licheniformis physiology. α‑CD showed a concentration‑dependent duality: low doses inhibited growth, but at 2 g/L it restored biomass formation and matched the control’s product yield.
The standout performer was DIMEB. At 2 g/L, it increased lichenysin production by 41.4% and improved specific productivity (g product per g biomass) by nearly 80%. Surface tension measurements confirmed that DIMEB‑supplemented cultures produced more active biosurfactant, and importantly, the CD did not interfere with downstream product recovery. The authors propose that DIMEB disrupts lichenysin micelles at low concentrations—temporarily increasing toxicity—but at higher concentrations effectively encapsulates the hydrophobic fatty‑acid tail of lichenysin, reducing membrane damage and enabling higher yields.
This work is the first to demonstrate that a methylated cyclodextrin derivative can outperform native CDs in biosurfactant fermentations. Beyond its immediate practical value, the study opens a new conceptual direction: using supramolecular chemistry to modulate microbial product inhibition. For industries relying on lipopeptide biosurfactants—cosmetics, detergents, bioremediation, and enhanced oil recovery—this represents a simple, scalable, and cost‑effective intensification strategy.
Future research will need to validate the proposed mechanisms using structural analyses (e.g., NMR, MS) and explore whether CD‑biosurfactant complexes can be tuned for other microbial systems. Still, the current findings already position DIMEB as a promising additive for greener, more efficient bioprocesses.
Reference:
Sakiyo, J. J., & Németh, Á. (2025). Investigation on Applying Cyclodextrins in a Fermentation Process for Enhanced Biosurfactant Production by Bacillus licheniformis. International Journal of Molecular Sciences, 26(21), 10518. https://doi.org/10.3390/ijms262110518