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The bacteriocins produced by Lactococcus lactis subsp. lactis C101910 (C101910) and NBRC 12007 (NBRC 12007) were used to prevent the growth of Lactobacillus hilgardii, a hiochi bacterium, at the mizu-koji stage in the sake brewing process. The bacteriocins produced by C101910 and NBRC 12007 were slowly inactivated in the koji extract by proteases, depending on the pH and temperature of the koji extract. However, the activities of bacteriocins from C101910 and NBRC 12007 remained about 50% and 70% of the initial values, respectively, even after incubation at pH 3 and 10℃ for 12 h. By adding the bacteriocin solutions, prepared according to the method reported previously, from C101910 and NBRC 12007 to koji extract (pH 3 and 10℃) at a volume ratio of 5% (v/v) and 1% (v/v), respectively, the number of viable L. hilgardii cells decreased to below the detection limit (1.0×102 cells/ml) from the initial concentration (3.2×105 cells/ml) within 12 h. In mizu-koji consisting of rice koji and lactic acid solution at pH 3 and 10℃, the growth-inhibitory effect of bacteriocins from C101910 and NBRC 12007 on L. hilgardii decreased as compared with that in koji extract. However, the number of viable L. hilgardii cells decreased by more than two orders of magnitude as compared with the initial value (1.0×105 cells/ml) by adding the bacteriocin solution at a volume ratio of 10% (v/v)., Lactococcus lactis subsp. lactis C101910（C101910）およびLactococcus lactis subsp. lactis NBRC 12007（NBRC 12007）が生産するバクテリオシンを用いて、清酒製造プロセスの中の水麹工程において、火落菌であるLactobacillus hilgardii の増殖を阻害することを検討した。C101910 およびNBRC 12007 が生産するバクテリオシンは、pH と温度に依存して、プロテアーゼ活性を有する麹抽出液中でゆっくりと失活した。しかし、C101910 およびNBRC 12007 が生産するバクテリオシンの活性は、pH 3、10℃の条件で12 時間処理した後でも、それぞれ初期の活性の約50％と約70％が残存していた。既に報告した方法に従って調製したC101910 およびNBRC 12007 由来のバクテリオシン溶液を、麹抽出液（pH 3、10℃）にそれぞれ5％（v/v）および1％（v/v）の割合で添加することによって、L. hilgardii の生細胞数は12 時間以内に、初期に添加した濃度（2.5-3.2×105cells/ml）に比べて検出限界（1.0×102 cells/ml）以下まで減少した。米麹と乳酸溶液を含む水麹（pH 3、10℃）中では、C101910 およびNBRC 12007 由来のバクテリオシンのL. hilgardii に対する増殖阻害活性は、麹抽出液中に比べて低下した。しかし、バクテリオシン溶液の添加割合を10％にすることによって、L.hilgardii の生細胞数は、初期に添加した値（1.0×105cells/ml）に比べて2 オーダ以上減少した。

Los lactobacilos heterofermentativos ailados de vino pertenecen a las especies Lactobacillus brevis, Lactobacillus hilgardii y Lactobacillus buchneri. Sin embargo, la taxonomía de estas especies es confusa puesto que a menudo los métodos fenotípicos convencionales producen identificaciones erróneas. La secuenciación del 16S rDNA es un método útil para la diferenciación de las especies de lactobacilos heterofermentativos aislados de vino. Mediante la secuenciación de un fragmento del gen recA también se ha podido discriminar entre las distintas especies de lactobacilos heterofermentativos.

The catabolic ornithine transcarbamylase (cOTC; EC 2.1.3.3) from the lactic acid bacteria Lactobacillus hilgardii is a key protein involved in the degradation of arginine during malolactic fermentation. cOTC containing an N-terminal His6 tag has been overexpressed in Escherichia coli, purified and crystallized under two different experimental conditions using the hanging-drop vapour-diffusion method. Crystals obtained from a solution containing 8%(w/v) PEG 4000, 75 mM sodium acetate pH 4.6 belong to the trigonal space group P321 and have unit-cell parameters a = b = 157.04, c = 79.28 Å. Conversely, crystals grown in 20%(v/v) 2-methyl-2,4-pentanediol, 7.5%(w/v) PEG 4000, 100 mM HEPES pH 7.8 belong to the monoclinic space group C2 and have unit-cell parameters a = 80.06, b = 148.90, c = 91.67 Å, [beta] = 100.25°. Diffraction data were collected in-house to 3.00 and 2.91 Å resolution for trigonal and monoclinic crystals, respectively. The estimated Matthews coefficient for the crystal forms were 2.36 and 2.24 Å3 Da-1, respectively, corresponding to 48% and 45% solvent content. In both cases, the results are consistent with the presence of three protein subunits in the asymmetric unit. The structure of cOTC has been determined by the molecular-replacement method using the atomic coordinates of cOTC from Pseudomonas aeruginosa (PDB code 1dxh) as the search model

Conventional phenotypic methods sometimes lead to misidentification of some heterofermentative wine lactobacilli such as Lactobacillus hilgardii, Lactobacillus buchneri, and Lactobacillus brevis. We establish the specificity of 16S rDNA sequencing in the differentiation of these species and in the rejection of the Lactobacillus vermiforme species name. Moreover, we succeeded in differentiating these heterofermentative species by means of recA gene sequence comparison. Short homologous regions were amplified by PCR with degenerate consensus primers, sequenced, and 280 bp were analysed and considered for the inference of phylogenetic trees. The phylogram obtained was coherent and clearly separated the three species. The recA gene sequence was a reliable and useful method that allowed a good discrimination among closely related species. The validity of the recA gene sequence, restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified 16S–23S rDNA intergenic spacer region (ISR), and random amplified polymorphic DNA (RAPD) to study the L. hilgardii intraspecies heterogeneity was tested in five strains isolated from stuck wine fermentations at the same winery in the same vintage. The results indicated that L. hilgardii is a heterogeneous species. Since L. hilgardii is a malolactic species that can influence the final quality of the wine, the presence of oenological relevant genes, such as those involved in ethyl carbamate or biogenic amine production, was investigated