Yeast pellets extruded

Bauer and co-workers (Rottenbacher, 1985 Rottenbacher et ah, 1987) carried out anaerobic fermentation under nitrogen gas at 18-20°C in a gas-tight closed circuit with a partial condenser followed by a gas adsorber for ethanol and water vapour recovery. The highest rate of ethanol production was about 50gh with a bed of 2.4 kg of extruded cylindrical baker s yeast pellets of diamefer 800 rm. This rate is less... 

Figure 6.3 Effect of fermentation medium composition on the rate of ethanol production from glucose using extruded yeast pellets. Reproduced from Hayes (1998) with permission.

Pellet mills (Fig. 5-10b2-b6, Chapter 5) are used in the food industry for the size enlargement of coffee and tea meal, herb powders, yeast, products with instant characteristics (for example mixtures of cocoa and powdered sugar, effervescent drink powders), and others. The cylindrical extrudates are bagged and used mostly by institutional customers (large kitchens). 

For example, the styrenic block copolymer, natural oil and brewer s yeast are mixed to obtain a semifluid product that is extruded at a temperature of about 120-180°C in such a way to obtain granules or pellets. The biodegradable compound can be used in an additional extrusion or molding process to get the final biodegradable product. Thus, a final pol)mieric material-based product is formed, that is biodegrading in a reasonable period of time in suitable composting sites (13). 

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