(571ao) Biosurfactants: Efficient Production and Applications

The proposed poster will set innovative methods for the recovery and purification of biosurfactants in the broader context of the need for sustainable alternatives to petrochemical based commercial surfactants.

The global market for surfactants is approximately 8 M tonnes per annum with a total value of $ 13.9b¹. The bulk of these surfactants are obtained from non-renewable oil-based feedstocks. Our rate of consumption of petrochemicals has reached a point that many believe to be unsustainable. An alternative route of surfactant production exists in nature; ?Carbohydrate-based surfactants, being based on plant-derived chemicals, use renewable resources, are readily biodegradable, non toxic and do not add to the Earth's CO₂ burden.?¹ Biosurfactants can be produced via fermentation, for example the heptapeptide surfactin, which has antibiotic properties, is a metabolite of Bacillus subtilis BBK006. Using genetic modification to insert a specific protein-expressing gene into a suitable host gives control over the production of biosurfactants during a fermentation.

A major obstacle to the economic production of biosurfactants, and hence their use instead of petrochemical based surfactants, is the downstream processing required. Separation techniques such as microfiltration are costly when applied to typical bioproduct process streams, i.e. large volumes, with a low product concentration. An alternative method for biosurfactant recovery is foam fractionation. Foam Fractionation is an adsorptive bubble separation method², which is used to enrich and partially separate solutions of surface active species³. Although foam fractionation dates from the 1960's its application to the recovery of biosurfactants from fermentations is relatively new⁴.

¹ Hargreaves, T. (2003) Surfactants: the ubiquitous amphiphiles. Chemistry World. Accessed online, 30/3/08 http://www.rsc.org/chemistryworld/Issues/2003/July/amphiphiles.asp

² Lemlich, R. (1968) Adsorptive bubble separation methods- Foam fractionation and allied techniques. Industrial and Engineering Chemistry. 60, 16-29.

³ Jashnanil, I.L. and Lemlich, R. (1973) Transfer units in foam fractionation. Ind. Eng. Chem. Process Des. Develop. 12, 312-321.

⁴ Chen, C., Baker, S.C. and Darton, R.C. (2006). Continuous production of biosurfactant with foam fractionation. J. Chem. Technol. Biotechnol. 81, 1915?1922.