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Sixteen strains of five genera of thermophilic bacteria, i.e., Alicyclobacillus, Brevibacillus, Geobacillus, Meiothermus, and Thermus, were cultivated at a temperature from 42 to 70 °C. Twelve strains were obtained from the Czech Collection of Microorganisms, while four were directly isolated and identified by 16S rRNA gene sequencing from the hot springs of the world-famous Carlsbad spa (Czech Republic). Polyprenol homologs from C40 to C65 as well as free undecaprenol (C55), undecaprenyl phosphate, and undecaprenyl diphosphate were identified by shotgun analysis and RP-HPLC/MS-ESI+ (reverse phase high-performance liquid chromatography–high-resolution positive electrospray ionization mass spectrometry). The limit of detection (50 pM) was determined for individual homologs and free polyprenols and their phosphates. Thus, it has been shown that at least some thermophilic bacteria produce not just the major C55 polyprenol as previously described, but a mixture of homologs.

Acetic acid bacteria (AAB) are often considered a threat of the past because today’s equipment allows to perform post-fermentation processes under greatly reduced level of oxygen. This paper deals with the current importance of AAB in brewing. The risk of contamination as well as functional role in spontaneously fermented sour beers is reviewed. The main harmful effect of AAB lies in the direct spoilage of draft beer and formation of biofilms, most often in dispensing systems. On contrary AAB seems to be indispensable in the case of sour beer production. A key issue of AAB in brewing environment is their (early) detection and identification. Therefore, part of this study is devoted to both the latest sophisticated methods and also those of traditional cultivation. which are still prevalent in operating laboratories due to their cost and easy implementation. Finally, the experimental and pictorial material is added as a guide for operations that have less experience with AAB.

High resolution electrospray ionization tandem mass spectrometry (HR-ESI-MS/MS) was used to analyze cardiolipins (Ptd2Gro) including their plasmalogen forms from three species of the anaerobic beer-spoilage bacterial genus Pectinatus. Cardiolipins including their plasmalogens were analyzed by HR-ESI-MS/MS on Orbitrap and almost 100 cardiolipins (i.e. tetra-acyl--Ptd2Gro, plasmenyl-tri-acyl--PlsPtd2Gro, and di-plasmenyl-di-acyl--Pls2Ptd2Gro) of three classes were identified. The structures of the molecular species that consist of various regioisomers and structurally similar compounds were revealed in detail. The high resolution mass spectrometry allowed the unambiguous structural assignment of Ptd2Gro, PlsPtd2Gro, and Pls2Ptd2Gro in the three species of Pectinatus, which contain predominantly odd numbered fatty acids.