Unclarified enzyme product

Another simple example is an unclarified enzyme product. In this case, the cells in the fermenter produce a target molecule, for example, a cellulase enzyme mixture. The enzyme mixture is the product, but the cells remain in the final product. This approach is preferable when a product has very low purity requirements and a separation process is cost prohibitive. Cellulase enzyme mix is used to break down biomass into glucose which enables the use of cellulosic raw materials as fermentation feedstocks (Himmel et al., 1999). This application requires a very inexpensive enzyme mix at low purity. Cellulases are also used in textile applications, where they are required in a purified form. 

FIGURE 6A Simplified recovery process schematic for an unclaiified enzyme product. 

The inactivated fermentation broth is stabilized further either by drying or through the addition of chemicals. The key stability aspects are the enzymatic activity and microbial stability. Antimicrobials and polyols are commonly added to the inactivated fermentation broth for stabilization, but the choice of chemicals is very restricted by 

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Other studies of the fate of indoleacetic acid in plant tissues have concentrated on non-oxidized products. It has been shown that indoleacetic acid can readily be esterified to its ethyl ester (XXIII) by plant enzymes, and there is some evidence this that is a naturally occurring substance. Similarly, when indoleacetic acid is applied to plant tissue it is rapidly conjugated into indoleacetamide (XVIII) and indoleacetylaspartic acid (XXII). The details of this process have been extensively studied by Andreae and his coworkersi, but the nature of the enzymes involved remains unclarified. AU three of these compounds can produce auxin effects when applied to tissue, hence they can act as indoleacetic acid precursors. However, the kinetics of the reactions which form them appear to favor the conjugated substances and they are more correctly considered as products rather than precursors of... 

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