Example 3 Scaling up the System Application to Industrial Production

1 Example 3 Scaling up the System Application to Industrial Production 

Natural esters are widely used by the aroma and fragrance industries because of their fruity or floral taste/odor. Many of them are alkyl esters of formic, acetic, propionic, and butyric acids. The development of an efficient biotechnological process, compatible with the natural label for the products but offering costs comparable to the costs of chemical processes, has been achieved, representing the first application of gas/solid technology on an industrial scale [51]. 

The process was then developed on a closed loop of nitrogen, circulating in three different zones, thus reducing the nitrogen consumption to zero during continuous operation. 

Figu re .8 Schematic diagram of an industrial continuous solid/gas bioreactor developed for the production of natural esters in a closed nitrogen loop. 

Different syntheses coupling Cl to C4 carboxylic acids and Cl to C9 alcohols for the industrial production of natural aromas were optimized, and production tests were performed. Table 11.2 summarizes some examples of the production rates of the system that can be achieved with an acid conversion exceeding 94% and a maximal excess of alcohol of 2 (mole per mole) in the worst cases ( ° -11 kj mol ) for a residence time commonly observed as low as 0.5 to 0.15 s. 

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