Brewing Microbiology – Bacteria of the Genera Bacillus, Brevibacillus and Paenibacillus and Cultivation Methods for their Detection – Part 1
Keywords:aerobic/facultative anaerobic bacteria, Bacillus, Bacillus cereus, Bacillus licheniformis, Brevibacillus, contamination of malt and beer, Paenibacillus
Bacteria of the genus Bacillus are often detected in brewing operations, but they rank among less hazardous contaminants. They are not able to survive in the vegetative form in beer and spoil it. Spores of Bacillus bacteria are present especially in malt and grain adjuncts. They are able to survive wort boiling, however in the following phases they are not able to germinate because of their sensitivity to bitter hop substances and low pH of fermenting wort and fi nished beer. We provide here an overview of basic morphological and physiological properties of these bacteria and describe their importance in brewing process. Particular attention is given to species B. cereus and B. licheniformis for which has been proved the presence of the horA gene, which is associated with resistence of lactic acid bacteria to hop substances. Species Brevibacillus brevis and Paenibacillus macerans, which were previously included in the genus Bacillus, are also described.