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A process model for approximating the production costs of the fermentative synthesis of sophorolipids

Richard D. Ashby, Andrew J. McAloon, Daniel K. Y. Solaiman, Winnie C. Yee, Marshall Reed
Journal of surfactants and detergents 2013 v.16 no.5 pp. 683-691
petroleum, sunflower oil, fermentation, equipment, glucose, operating costs, sophorolipids, surfactants, labor, production costs, econometric models, computer software, feedstocks, oleic acid, capital
Sophorolipids are microbial glycolipids that possess surfactant-type properties and have been successfully tested in a number of potential industrial and niche applications but they are generally acknowledged to require higher production costs when compared to petroleum-based surfactants. The objective of this study was to develop a process economic model for the fermentative synthesis of sophorolipids using contemporary process simulation software and current reagent, equipment, and supply costs, following current production practices. Glucose (Glc) and either high oleic sunflower oil (HOSO) or oleic acid (OA) were used as feedstocks and the annual production capacity of the plant was set at 90.7 million kg/yr with continuous operation of 24 h a day for 330 days per year. Facility construction costs and major equipment specification were calculated to be US$17.1 million but other considerations such as capital, labor, material and utilities costs were also included. The single greatest contributor to the overall production/operating cost was the cost of raw materials, which accounted for 89% and 87% of the total estimated production expenditures for the HOSO and oleic acid-based fermentations, respectively. Based on this model and assuming yields of 100 g/L, the cost of large-scale sophorolipid synthesis via fermentation from Glc:HOSO was calculated to be US$2.95/kg ($1.34/lb) and from Glc:OA to be US$2.54/kg ($1.15/lb). The model is flexible and can be adjusted to reflect changes in capital, production and feedstock costs as well as changes in the type of feedstocks used.