Conversion of glycerol to 1,3-propanediol (1,3-PDO) is an attractive option to increase the economic efficiency of the biofuel industry. A bacterial strain that produced 1,3-PDO in the presence of glycerol was isolated from thin stillage, the fermentation residue of bioethanol production. This 1,3-PDO-producing organism was identified as Lactobacillus panis through biochemical characteristics and by 16S rRNA sequencing. Characterization of the L. panis strain hereafter designated as PM1 revealed it was an aerotolerant acidophilic anaerobe able to grow over a wide range of temperatures; tolerant to high concentrations of sodium chloride, ethanol, acetic acid, and lactic acid; and resistant to many common antibiotics. L. panis PM1 could utilize glucose, lactose, galactose, maltose, xylose, and arabinose, but could not grow on sucrose or fructose. Production of 1,3-PDO by L. panis PM1 occurred only when glucose was available as the carbon source in the absence of oxygen. These metabolic characteristics strongly suggested NADH recycling for glucose metabolism is achieved through 1,3-PDO production by this strain. These characteristics classified L. panis PM1 within the group III heterofermentative lactic acid bacteria, which includes the well-characterized 1,3-PDO-producing strain, Lactobacillus reuteri. Metabolite production profiles showed that L. panis PM1 produced considerable amounts of succinic acid (~11-12 mM) from normal MRS medium, which distinguishes this strain from L. reuteri strains.

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Pediococcus claussenii is a common brewery contaminant. We have sequenced the chromosome and plasmids of the type strain P. claussenii ATCC BAA-344. A ropy variant was chosen for sequencing to obtain genetic information related to growth in beer, as well as exopolysaccharide and possibly biofilm formation by this organism.

An ATP-binding cassette (ABC) multi-drug resistance (MDR) gene was found in 4 Gram-positive bacterial isolates of environmental origin and found capable of spoiling beer. The bacteria isolated were Bacillus cereus, Bacillus licheniformis, Paenibacillus humicus, and Staphylococcus epidermidis; all of which were previously unappreciated as beer-spoilage bacteria. The MDR gene found in these bacteria has less than 37% similarity to known ABC MDR proteins described for Bacillus and Staphylococcus, and this is the first finding of an ABC MDR gene in the genus Paenibacillus. The sequenced region of the gene was translated and compared phylogenetically with the closest GenBank matches of the respective species and the closest GenBank matches overall. The ABC MDR proteins from these isolates were found to cluster among known sequences of HorA, sharing 99.5% identity within the sequenced region. In the beer-spoilage-associated genera Lactobacillus and Pediococcus, the presence of the MDR gene horA correlates with the ability to grow in beer. As the unique horA-harbouring isolates described here are capable of growing in beer, it is likely that the presence of the horA gene likewise confers hop resistance to these organisms.