Current Developments in the Genetic Manipulation of Brewing Yeast Strains-a Review*

Biological processes have been employed in industry for centuries. However, recent advances in both cell and molecular biology have permitted more confident predictions that a given product can be produced by a biological process or organism at a reasonable cost. Genetic manipulation has become a practical and quite general proposition. This advance has evolved into a separate discipline known as biotechnology which has economic potential as important as atomic physics, electronics, and microelectronics. These developments in biotechnology are as applicable to brewer's yeast strains as they are to any other biological system. With the advent of spheroplast fusion and transformation, the capability exists to ‘modify’ existing yeast strains to enable them to ferment at a faster rate, tolerate high concentrations of ethanol, alter their flocculation properties, increase the number of metabolisable sugars, adjust the metabolic byproducts, etc. Fusion has been found to be too non-specific to genetically modify existing brewer's yeast strains in a controllable fashion; nevertheless, it is an invaluable technique for producing novel strains from brewing and other industrial strains. Transformation, particularly with the aid of recombinant DNA techniques, is a more subtle method for introducing single gene traits into strains. However, before such manipulations can be realistically undertaken, detailed biochemical knowledge of the system to be incorporated or modified must be available.