ABSTRACT
The development of microbial biotechnology can conveniently be regarded as having taken place in four phases, each representing a stage in technological development. The function of the mashing stage is to convert starch to fermentable sugars and to extract them from the malt together with other nutrients. The combined actions of the amylases during mashing break down starch to a complex mixture of sugars and dextrins. A continuous fermentation process using a tower fermenter has been described and the build-up of contaminating organisms must be avoided. Acid treatment was less favoured because it tended to produce a lower yield of fermentable sugars. After milling in roller or hammer mills to obtain a fine meal, or wet milling and separation of the starch fraction, the substrate was cooked. The microbiological industries producing bulk products are subject to fewer constraints on the use of new technology.
