Bioconversion of Sodium Dodecyl Sulphate to Rhamnolipid by Pseudomonas aeruginosa: A Novel and Cost-Effective Production Strategy

Abstract

The utility of rhamnolipids in industry is currently limited due to the high constraints in its economic production. In this scenario, the novel utility of sodium dodecyl sulphate (SDS) as carbon source could serve as promising cost-effective strategy. Screening of effective SDS biodegraders led to the isolation of Pseudomonas aeruginosa S15 capable of concomitant SDS degradation and biosurfactant synthesis. SDS-based rhamnolipid production was proved on SDS minimal agar plates using cetyl trimethylammonium bromide-methylene blue method and optimised in SDS-based minimal salt (SBS) medium. SDS proved to be an ideal carbon source for rhamnolipid synthesis with a high substrate to product conversion rate yielding 6.9 g/l of rhamnolipids from 1 g/l SDS in 5 days. Fast atom bombardment mass spectroscopy analysis of the purified biosurfactant proved the presence of mono- and di-rhamnolipids, viz., Rha-C(10)-C(10), Rha-C(10)-C(12) and Rha-Rha-C(10)-C(10) with surface active properties. The secreted rhamnolipids were not utilised by S15 as a carbon source, but it caused a dispersion of bacterial biofilms in SBS medium. To the best of our knowledge, this is the first report on bioconversion of synthetic detergent to biodetergent. This SDS-based novel methodology presents a more economised mode of rhamnolipid synthesis utilising SDS as sole carbon source.

Bioconversion of sodium dodecyl sulphate to rhamnolipids by transformedEscherichia coliDH5αcells-a novel strategy for rhamnolipid synthesis

“…The best SDS degrading isolate S15 was also capable of converting SDS to a rhamnolipid (Rebello et al . ) and thus S15 was selected for further study. The isolate S15 exhibited a slower rate of growth in SDS based medium in comparison to sucrose‐based medium, indicating its stress during growth in presence of SDS (Fig.…”

“…The rhamnolipid was extracted, purified and characterized as explained in (Rebello et al . ). The anionic nature of the purified rhamnolipid was analyzed by MBAS assay (Hayashi ), presence of rhamnose was done by quantification of l ‐rhamnose by the 6‐deoxy‐hexose method spectrophotometrically with orcinol (Chandrasekaran and Bemiller ) and the mass was verified by fast atom bombardment mass spectrum (FAB‐ MS).…”

Biosurfactant Facilitated Biodegradation of Quinalphos at High Concentrations byPseudomonas aeruginosaQ10

“…The influence of nitrogen sources on rhamnolipid production is previously reported (Rebello et al, 2013).…”

Pollutant Diseases, Remediation and Recycling

“…Optimized biosurfactant production by an integrated rational whole-cell biocatalyst and bioprocess design methodology, termed systems biotechnology has also been described (Muller and Hausmann 2011 ). A novel method of SDS based rhamnolipid synthesis is also been introduced yielding a high 304 substrate to product conversion ratio (Rebello et al 2013 ). However, current biosurfactant research has advanced far ahead providing signifi cant opportunities to replace chemical surfactants with sustainable biologically produced alternatives in bulk commercial products.…”