ABSTRACT
The annual worldwide consumption of chemical surfactants is estimated to be of the order of 13 million tons (Marchant and Banat 2012a); if biosurfactants can be used to replace even a small proportion of this market, the resulting production capacity would need to be very large (Marchant and Banat 2012b). As a result of this need for large-scale production, certain characteristics of the microbial biosurfactant-producing systems have become very important. These include substrate costs, product yield, and the potential costs of downstream processing, particularly where a mixture of congeners with different functionalities are produced. A wide range of biosurfactant-producing microorganisms have already been identied and investigated; these include bacteria, yeasts, and fungi. The majority of these organisms have little future as industrial scale producers, mainly due to the low yields of product that can be obtained in fermentations.
