ISBN 978-3-8439-1857-2

978-3-8439-1857-2, Reihe Verfahrenstechnik

Andreas Weber
Process Analysis of Biosurfactant Downstream Processing

191 Seiten, Dissertation Technische Universität Dortmund (2014), Softcover, A5

Zusammenfassung / Abstract

Economic potential of biosurfactants is up to now limited because of inefficient production and strong competition with conventional chemical surfactants. To overcome these limitations, up- and downstream processing of sophorolipid production with Starmerella bombicola is analysed in this work to identify production cost relevant parameters and direct research effort in the early stage of process development accordingly.

It is shown that substrate costs dominate production costs of sophorolipids (62 - 82%), which emphasises the importance of high substrate yield and conversion of inexpensive substrates in microbial cultivation. Therefore, the substrate-cost-to-sales ratio (SCS) was defined to check, if economic production is feasible and to evaluate cultivation and substrate alternatives. For a product price of 3000 €/t, the SCS of sophorolipids based on renewable resources is 0.36 to 0.42 €substrate/€SL, indicating economic production.

Since high substrate costs are unavoidable for products of white biotechnology, a cost efficient downstream process is mandatory. Therefore, unit operations for biosurfactant downstream processing were screened and evaluated and possible process options for three sophorolipid products were developed. In the next step, feasibility was proven experimentally and necessary data for modelling of the selected unit operations washing, extraction, hydrolysis and crystallisation were estimated. The impact of uncertain input data, either due to error prone experimental data or necessary assumptions, on production costs was investigated in detailed process analysis. Furthermore, it was shown that by using genetically modified strains, production costs (-12.8%) and environmental impact of acidic sophorolipid production can be reduced significantly.

A mixture of sophorolipids can be produced for 1.50 to 1.68 €/kg, depending on purity requirements, whereas for strictly acidic or lactonic sophorolipids, production cost increase to 1.91 to 2.19 €/kg.