Brewing Microbiology - Bacteria of the Genera Bacillus, Brevibacillus and Paenibacillus and Cultivation Methods for their Detection - Part 1

Abstract

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.Brožová, M., Kubizniaková, P., Matoulková, D., 2018: Mikrobiologie pivovarské výroby -bakterie rodů Bacillus, Brevibacillus a Paenibacillus a kultivační metody pro jejich detekci -1. část. Kvasny Prum., 64(2): 50-57Bakterie rodu Bacillus jsou v pivovarských provozech často detekovány, řadí se však mezi méně rizikové kontaminanty. Ve vegetativní formě nejsou schopné přežívat v pivu a nekazí ho. Spory bakterií Bacillus jsou přítomny zejména ve sladu a obilných náhražkách sladu, přežijí chmelovar, ale v navazujících fázích výroby piva nevyklíčí -jsou citlivé na hořké chmelové látky a nízké pH kvasící mladiny a hotového piva. V publikaci jsou popsány základní morfologické a fysiologické vlastnosti těchto bakterií, je zde popsán jejich význam v procesu výroby piva. Zvláštní pozornost je věnována druhům B. cereus a B. licheniformis, u kterých byla prokázána přítomnost genu horA, který je spojován s rezistencí bakterií mléčného kvašení k chmelovým látkám. Publikace se dále věnuje druhům Brevibacillus brevis a Paenibacillus macerans, které byly dříve řazeny do rodu Bacillus. (meat, vegetables, milk, cereals). Due to their frequent occurrence in nature and thermoresistant spores, they enter the brewing operation mostly with raw materials (water, malt, hop). Bacillus bacteria are able to survive mashing and wort boiling, therefore they can also be found in fi nished beer (Back, 2005;Vaughan et al., 2005). However, in most species their following growth in beer is inhibited by bitter hop products and acid pH (Back, 2005;Basařová et al., 2010). Generally, they are not considered hazardous brewing contaminants, due to their inability to grow in beer, nor after adaptation to outer conditions, and the fact that they do not affect biological stability of fi nished beer. Undesirable is the ability of some bacilli to reduce nitrates to nitrites that may cause the formation of N-nitrosamines in beer (Back, 2005;Bokulich and Bamforth, 2013;Briggs et al., 2004). Keywords ■ 2 GENERAL CHARACTERISTICS OF GENUS BACILLUSBacteria of the genus Bacillus are aerobic or facultative anaerobic,...

Proteomic identification of beer brewing products in the ground layer of Danish Golden Age paintings

“…S6). These two compounds are produced by various micro-organisms in the Bacillus and Lactobacillus genera respectively, both of which can attack and cause spoilage in food products such as dough, bread, and beer ( 27 – 29 ). Matches to these two compounds were only found in samples in which proteomics identified cereal and yeast proteins.…”

“…On the other hand, spectral matches for esperin and acidocin were found only in samples containing cereal and yeast proteins, from paintings A and D and paintings E and F, respectively. Esperin is an antibiotic produced by Bacillus mesentericus ( 63 ), a food contaminant also found in bread dough and beer ( 27 ). Acidocin is a bacteriocin produced by Lactobacillus acidophilus ( 29 ), one of the Lactobacillus species infamously known for infecting beer ( 64 ), but that can also be used to increase the beverage’s sourness ( 65 ) and in sourdough baking products ( 66 ).…”

Quantitative and Qualitative Composition of Bacterial Communities of Malting Barley Grain and Malt during Long-Term Storage

“…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 finished beer [28]. Some Bacillus species may cause food poisoning.…”

Controlling the Risk of Bacillus in Food Using Berries

“…The growth of genus Bacillus bacteria is inhibited especially by acid pH. However, some studies showed that Bacillus cereus could be able to survive and to grow for a certain period of time even at pH 4.2 -4.8 [39].…”