The properties of an anaerobic, rod-shaped bacterium having an unusual flagellar arrangement are described. The flagella emanate from only one side of the cell body and are not limited to the center portion as they are with selenomonads. The organism is a gramnegative, nonsporeforming mesophile producing acetic, propionic, and succinic acids and traces of lactic acid from glucose fermentation. The guanine-plus-cytosine content of the deoxyribonuleic acid is 39.8 mol%. The characteristics of this organism indicate that it belongs in none of the presently described genera. For this organism, we propose a new genus, Pectinatus, and a new species, Pectinatus cerevisiiphilus, in the family Bacteroidaceae. The type strain, CCC B-1022, has been deposited in the American Type Culture Collection under the number 29359.Few organisms are capable of growing in normal packaged beers because of the inherent selectivity brought about by pH, alcohol content, hop residuals, and the lack of oxygen. The organisms generally referred to as "beer spoilage bacteria" are classified in the following genera: Acetobacter, Acetomonas, Lactobacillus, Pediococcus, and Zymomonas. Other bacteria, such as enterobacters and flavobacteria, are considered to be problems in the early brewing process but never in the final packaged product (1). During the course of routine identification work on bacteria in our brewery, we isolated an unusual bacterium capable of growing in beer. Unlike other common organisms, this organism was a strict anaerobe, producing no growth aerobically on solid media. Under anaerobic conditions it fermented several sugars. Scanning electron microscopy (SEM) revealed that flagella were attached on only one side of the cell body, giving the cells the appearance of hair combs. The unique features of this organism clearly indicated that it was not a "typical" beer bacterium, and to our knowledge an organism of this type has not, to date, been described in the literature. The purpose of this study was to present some of the morphological and biochemical characteristics of this new isolate and to determine its taxonomic position.
MATERIALS AND METHODSBacterial strain. Only one strain (CCC B-1022) was studied. It was isolated from beer which had been stored at 30°C for 30 days. Stock cultures were maintained by biweekly transfers in freshly prepared MRS lactobacilli broth (Difco) with minimal head space in the tube and with incubation at 30°C. Between transfers, cultures were stored at 2°C.Media. For sugar utilization tests and for gas chromatographic analyses of volatile and nonvolatile fatty acids, prereduced media were used as described in the VPI Anaerobe Laboratory Manual (4). Cultures were grown in MRS lactobacilli broth (Difco) for determination of deoxyribonucleic acid (DNA) base composition, for preparation of cells for SEM photography, and for thin sections for electron microscopy. Thioglycolate agar with glucose (Difco) was used to obtain growth on solid media in Hungate roll tubes (5).Biochemical tests. Peptone yeast e...
