Economic analysis of lipase production by Penicillium restrictum in solid-state and submerged fermentations

In the present work an economic analysis of the production of Penicillium restrictum lipase in both submerged (SF) and solid state fermentations (SSF) was performed. For a production scale of 100 m(3) lipase concentrate per year, total capital investment needed for the submerged process was 78% higher than that needed for the solid-state fermentation process. The submerged process proved to be economically unfeasible, as unitary product cost was 68% higher than the product selling price. Contrastingly, the solid-state fermentation process turned out to be very attractive from an economic point of view. Also for a scale of 100 m(3)/year, SSF unitary product cost was 47% lower than the selling price, payback time was 1.5 years, return on investment was 68% and internal return rate was 62% for a 5-year-project life. Furthermore, the profitability of this process remained high even with eventual increases of 40% in product concentration or total capital investment, or decreases of 20% in product price. The great advantage of the SSF process is the extremely cheap raw material it uses as main substrate. (C) 2000 Elsevier Science S.A. All rights reserved.