99A-3 |
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R. O. MORAWICKI1, R. B. Beelman1, D. G. Peterson1, and A. Demirci2. (1) Dept. of Food Science, Pennsylvania State Univ., 20 Borland Lab., University Park, PA 16802-2503, (2) Dept. of Agricultural & Biological Engineering, Pennsylvania State Univ., 249 Agricultural Engineering Bldg., University Park, PA 16802 The breakdown of linoleic acid catalized by enzymes contained in several mushroom species generates 1-octen-3-ol and 10-oxo trans-8-decenoic acid (ODA). This biosynthetic pathway may be used at industrial scale to produce natural 1-octen-3-ol, an expensive food flavor, and ODA, a fungal hormone that has also antimicrobial activity. This reaction, catalyzed with enzymes in a crude homogenate of Agaricus bisporus, was scaled up from a standard 1-L to a non-standard 10-L bioreactor using two different approaches: a constant power per volume of liquid (CPVL) and a constant volumetric mass transfer coefficient (kLa). For this non-Newtonian reaction operating with low solubility substrates, stirring speed was considered the most important controlling factor for the scaling up process. Therefore, the minimum critical stirring speed and kLa were determined experimentally for the 1-L reactor using an aeration rate of 0.44 m3 m-3 h-1. It was found that 600 rpm is the critical speed that produces a kLa of 40.2 h-1. With the critical speed for the 1-L reactor, the stirrer speed was mathematically calculated for the 10-L reactor using the CPVL principle. It was then experimentally demonstrated that the predicted value of 364 rpm was too low to maintain the same yield than in the 1-L reactor. For the constant kLa strategy, kLa was experimentally determined at different stirring speeds for the 10-L reactor, using a deactivated mushroom homogenate, until was found that 750 rpm produces a kLa of 40.2 h-1. Confirmatory reactions were run in both 1-L and 10-L reactors, at 600 rpm and 750 rpm respectively, finding similar final concentrations. The constant kLa value has proved to be effective to scale up this reaction from a 1-L to a 10-L reactor, so it could be used as scaling up strategy for larger reactors.
Session 99A, Biotechnology: General
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