Alkanolamide biosurfactants: techno-economic evaluation of enzymatic versus chemical production

Alkanolamides are biosurfactants used in a range of products for cleaning and other applications. Recently, an environmentally benign and volume-efficient biocatalytic process for production of high-quality alkanolamides was developed in our laboratory. In the current investigation, this process is evaluated in terms of technical and economic feasibility on a multi-tonne scale using commercial process optimization software and compared with known chemical processes. Energy demands for the processes and in raw material production were also compared. A campaign for manufacturing 200 tonnes of alkanolamides was considered. When using a 20 m3 reactor and 5% (w/w) loading of an immobilized lipase (Novozym®435; Novozymes), 20 batches and a total process time of 101 hours are required for the whole campaign. The biocatalytic process was relatively more energy-efficient, but production costs were calculated to be about 1.4 times that of the corresponding conventional alkanolamide manufacturing process utilizing sodium methylate as a catalyst. The principal contributor to the extra costs is the cost of the immobilized enzyme. There is a great potential to decrease enzyme costs; industrialization may, however, depend on the possibility of obtaining a higher price for the biocatalytic product.