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Pectinatus cerevisiiphilusis a strictly-anaerobic, beer-spoilage bacterium. Propionate, acetate and hydrogen sulphide are the major metabolic products of this micro-organism and are responsible for off-flavour of beer. The growth kinetics and the effects of temperature, pH and metabolic activity ofP. cerevisiiphilusonSaccharomyces cerevisiaein mixed culture, in wort medium were studied. The growth of S. cerevisiae was inhibited in mixed culture when the temperature was greater than 15°C; the effect was maximal at 32°C at the optimal temperature for growth ofP. cerevisiiphilus. Both the pH and the fermentation products, prionate (above 33 mmol l−1) and acetate (above 27 mmol l−1), produced byP. cerevisiiphiluslimited the growth and alcohol production ofS. cerevisiaein mixed culture. |
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