Effect of rhamnolipid on the physicochemical properties and interaction of bacteria and fungi

Abstract

Bacterial adhesion on surfaces is an essential initial step in promoting bacterial mobilization for soil bioremediation process. Modification of the cell surface is required to improve the adhesion of bacteria. The modification of physicochemical properties by rhamnolipid to Pseudomonas putida KT2442, Rhodococcus erythropolis 3586 and Aspergillus brasiliensis ATCC 16404 strains was analysed using contact angle measurements. The surface energy and total free energy of adhesion were calculated to predict the adhesion of both bacteria strains on the A. brasiliensis surface. The study of bacterial adhesion was carried out to evaluate experimental value with the theoretical results. Bacteria and fungi physicochemical properties were modified significantly when treated with rhamnolipid. The adhesion rate of P. putida improved by 16% with the addition of rhamnolipid (below 1 CMC), while the increase of rhamnolipid concentration beyond 1 CMC did not further enhance the bacterial adhesion. The addition of rhamnolipid did not affect the adhesion of R. erythropolis. A good relationship has been obtained in which water contact angle and surface energy of fungal surfaces are the major factors contributing to the bacterial adhesion. The adhesion is mainly driven by acid-base interaction. This finding provides insight to the role of physicochemical properties in controlling the bacterial adhesion on the fungal surface to enhance bacteria transport in soil bioremediation.

Remediation of Organic Contaminant in Sludge by using Bioaugmentation and Solidification and Stabilization (S/S) Method

“…Then, 1 ml of the fungal spore suspension was transferred to 1 ml of saline solution for the experiment purpose. The suspension was adjusted to an absorbance of between 0.9 and 1.0 at 600 nm to give between 5×10 10 spore/ml [19,20].…”

Antibacterial Mechanism of Rhamnolipids against Bacillus cereus and Its Application in Fresh Wet Noodles

“…Rhamnolipids (RLs), a type of glycolipid biosurfactant, have been observed to possess various properties and physiological activities, including antibacterial, emulsifying and antiviral abilities [7][8][9]. Pseudomonas strains are known to be the most efficient producers of glycolipids that contain rhamnose and 3-hydroxy fatty acids.…”