Inhibition of Bacterial Adhesion and Antibiofilm Activities of a Glycolipid Biosurfactant from Lactobacillus rhamnosus with Its Physicochemical and Functional Properties

Abstract

Biosurfactants derived from different microbes are an alternative to chemical surfactants, which have broad applications in food, oil, biodegradation, cosmetic, agriculture, pesticide and medicine/pharmaceutical industries. This is due to their environmentally friendly, biocompatible, biodegradable, effectiveness to work under various environmental conditions and non-toxic nature. Lactic acid bacteria (LAB)-derived glycolipid biosurfactants can play a major role in preventing bacterial attachment, biofilm eradication and related infections in various clinical settings and industries. Hence, it is important to explore and identify the novel molecule/method for the treatment of biofilms of pathogenic bacteria. In the present study, a probiotic Lactobacillus rhamnosus (L. rhamnosus) strain was isolated from human breast milk. Firstly, its ability to produce biosurfactants, and its physicochemical and functional properties (critical micelle concentration (CMC), reduction in surface tension, emulsification index (% EI24), etc.) were evaluated. Secondly, inhibition of bacterial adhesion and biofilm eradication by cell-bound biosurfactants from L. rhamnosus was performed against various biofilm-forming pathogens (B. subtilis, P. aeruginosa, S. aureus and E. coli). Finally, bacterial cell damage, viability of cells within the biofilm, exopolysaccharide (EPS) production and identification of the structural analogues of the crude biosurfactant via gas chromatography–mass spectrometry (GC–MS) analysis were also evaluated. As a result, L. rhamnosus was found to produce 4.32 ± 0.19 g/L biosurfactant that displayed a CMC of 3.0 g/L and reduced the surface tension from 71.12 ± 0.73 mN/m to 41.76 ± 0.60 mN/m. L. rhamnosus cell-bound crude biosurfactant was found to be effective against all the tested bacterial pathogens. It displayed potent anti-adhesion and antibiofilm ability by inhibiting the bacterial attachment to surfaces, leading to the disruption of biofilm formation by altering the integrity and viability of bacterial cells within biofilms. Our results also confirm the ability of the L. rhamnosus cell-bound-derived biosurfactant to damage the architecture of the biofilm matrix, as a result of the reduced total EPS content. Our findings may be further explored as a green alternative/approach to chemically synthesized toxic antibiofilm agents for controlling bacterial adhesion and biofilm eradication.

Lactiplantibacillus plantarum-Derived Biosurfactant Attenuates Quorum Sensing-Mediated Virulence and Biofilm Formation in Pseudomonas aeruginosa and Chromobacterium violaceum

“…A 16S rRNA gene sequencing method was applied for the identification of isolated LAB. Furthermore, the sequence match analysis of the identified LAB was carried out using the basic local alignment search tool (BLAST) on NCBI, and the obtained sequence was submitted to GenBank [ 22 ].…”

“…The confirmation of a cell-bound biosurfactant produced by isolated LAB was carried out using various quantitative and qualitative assays, such as emulsification assay, drop collapse assay, oil spreading assay, and blue agar plate (BAP) assay per our previous studies [ 22 , 23 ].…”

“…GC–MS analysis and characterization were carried out as previously described [ 22 , 23 ]. Identification of a crude biosurfactant structural analog was achieved by using a Shimadzu Nexis GC-2030 apparatus equipped with QP2020 NX-MS.…”

“…The ability of a few LAB to produce biosurfactants and their various applications, such as in the inhibition of microbial adhesion, desorption activity, and biofilm inhibition on a variety of surfaces, such as polypropylene, rubber, silicone, and different medical devices/instruments and implants, has been reported in a number of studies [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Recently, we reported that a few LAB strains can efficiently produce biosurfactants, and demonstrated the antibacterial and antibiofilm potential of a biosurfactant produced from LAB [ 22 , 23 ]. In this study, we hypothesized that LAB may also be a prospective source of novel anti-QS compounds.…”

Lacticaseibacillus rhamnosus: A Suitable Candidate for the Construction of Novel Bioengineered Probiotic Strains for Targeted Pathogen Control

“…In yet another study, L. rhamnosus isolated from breastmilk was shown to produce a biosurfactant with antibiofilm properties against Bacillus subtilis, Pseudomonas aeruginosa, S. aureus, and E. coli. This glycolipid biosurfactant reportedly inhibits the attachment of the pathogens to the surfaces, consequently disrupting biofilm formation through the alteration of the integrity and viability of the bacteria within the biofilms [104].…”