Microbial composition of biofilms in a brewery investigated by fatty acid analysis, fluorescence in situ hybridisation and isolation techniques

Abstract

Biofilms associated with brewery plants can harbour spoiling microorganisms that potentially damage the final product. Most beer-spoiling microorganisms are thought to depend on numerous interactions with the accompanying microbiota. However, there is no information on the microbial community structure of biofilms from bottling plants. The conveyors that transport the bottles to and from the plant are known as potential sources of microbial contamination of beer. Consequently, the material buildup from two conveyors was analysed using a cultivation/isolation approach, and the culture-independent techniques of whole cell fatty acid analysis and fluorescence in situ hybridisation (FISH). Heterogeneous communities were present at both conveyors. Although characteristic fatty acids for Eukarya were present, FISH-signals for Eukarya were extremely low. The Proteobacteria, in particular the Gammaproteobacteria, were abundant at both sample sites. Bacterial isolates were obtained for every dominating group detected by FISH: the Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria, the Xanthomonadaceae, the Actinobacteria, the Bacteroidetes and the Firmicutes.

Community Structure and Diversity of Biofilms from a Beer Bottling Plant as Revealed Using 16S rRNA Gene Clone Libraries

“…This negligible abundance or even absence of beer-spoiling bacteria is in line with results of a previous analysis of infeed and discharge conveyor biofilms from this brewery (47). Eight ARDRA patterns from the clone libraries were identical to those from strains isolated previously from this plant.…”

“…The gels were stained with ethidium bromide (1 g ml Ϫ1 ). Images were acquired by using a charge-coupled-device camera and analyzed by using the software packages Most of these strains were described previously (47). Clones with identical ARDRA patterns were grouped and were referred to as ARDRA groups.…”

Chryseobacterium ureilyticum sp. nov., Chryseobacterium gambrini sp. nov., Chryseobacterium pallidum sp. nov. and Chryseobacterium molle sp. nov., isolated from beer-bottling plants

“…Strain DW3 T was isolated from a biofilm collected from a bottling plant conveyor (Timke et al, 2004), whereas strains 5-1St1a T , 26-3St2b T and F-Fue-04IIIaaaa T were isolated from cleaned steel coupons that were mounted onto the outer surfaces of the beer-bottling plant and exposed overnight to the airborne microbiota of the filling area. The type strains of C. defluvii and Chryseobacterium formosense were used as reference strains (Kämpfer et al, 2003;Young et al, 2005).…”

Occurrence of Pectinatus and Megasphaera in the Major UK Breweries

“…Yeast and Lactobacillus species can dwell in these slimes, while the lactic acid produced by Lactobacillus species can be metabolized to propionic acid by anaerobic bacteria such as Pectinatus species, which can cause undesirable changes to final products 52 . Detection of low levels of Pectinatus from biofilms on a conveyor belt in a beer bottling line based on fatty acid profiles has previously been reported 53 . The presence of Pectinatus and Megasphaera species in fermentation areas and bottling lines of the four major breweries in the UK (breweries one, two, three and five) shows that Pectinatus and Megasphaera species are natural inhabitants of the breweries in the UK and not infrequent invaders.…”

“…Their presence in highly aerobic conditions provides basic knowledge about the complexity of these biofilms. It is thought that anaerobic bacteria dwell in well established biofilms 6,53 . Contamination could also occur in drainage areas and in floors with defects, areas which are often anaerobic.…”