ABSTRACT
Although microbial biosurfactants (BSs) are gaining momentum with an increasing number of companies active in this field, still their market share accounts for only a fraction of the global surfactant market (< 0.1 %). The fact that chemically produced BSs like alkyl polyglycosides (APGs) and sucrose-esters together already account to up to 4 % of the market shows that there is room for bio-based alternatives. However, to make this a reality, there are a few major bottlenecks and drawbacks associated with microbial BSs that need to be resolved. These issues can generally be summarized under: uniformity, diversity and efficiency. Resolving these key issues is the key to increase the market share of microbial BSs.
In this chapter, an integrated bioprocess design (IBD) approach is described to resolve these three major issues. In such IBD approach, strain engineering, process development and application research are closely interconnected and integrated. IBD approach is illustrated for the well-known BS producing yeast strain Starmerella bombicola. Strain engineering is described as a viable and powerful technique to drastically increase diversity and uniformity. A portfolio of new to nature glycolipid BSs, which can be produced in a uniform fashion and with diverse characteristics and thus application potential, has been developed. Moreover, further development and optimization of molecular tools will allow the further increase of efficiencies of production strains. Process development and optimization was subsequently shown to enable significant optimization (x20) of the production efficiency and final purity (> 95 %). Finally, the scale up of the developed and optimized processes allowed the generation of a production cost simulation model, which showed that further increasing the productivities (and scale) will allow the production costs to drop to 10 euro/kg for a new type of “bola” sophorolipids (SLs). To conclude, the authors confirm that applying the IBD strategy, i.e. considering the entire innovation chain, from genetic engineering through fermentation and downstream processing to final application testing, is the key to develop new strains and processes for the industrial production and commercialization of new biosurfactants and with expansion potentially other types of (non drop in) biochemicals.
