del Rio Beatriz, Ladero Victor, Redruello Begoña, Linares Daniel M, Fernández Maria, Martín Maria Cruz, Alvarez Miguel A
Instituto de Productos Lácteos de Asturias, IPLA-CSIC, Paseo Rio Linares s/n, 33300 Villaviciosa, Spain.
Food Microbiol. 2015 Jun;48:163-70. doi: 10.1016/j.fm.2014.11.018. Epub 2014 Dec 24.
Lactococcus lactis is the lactic acid bacterial (LAB) species most widely used as a primary starter in the dairy industry. However, several strains of L. lactis produce the biogenic amine putrescine via the agmatine deiminase (AGDI) pathway. We previously reported the putrescine biosynthesis pathway in L. lactis subsp. cremoris GE2-14 to be regulated by carbon catabolic repression (CCR) via glucose but not lactose (Linares et al., 2013). The present study shows that both these sugars repress putrescine biosynthesis in L. lactis subsp. lactis T3/33, a strain isolated from a Spanish artisanal cheese. Furthermore, we demonstrated that both glucose and lactose repressed the transcriptional activity of the aguBDAC catabolic genes of the AGDI route. Finally, a screening performed in putrescine-producing dairy L. lactis strains determined that putrescine biosynthesis was repressed by lactose in all the L. lactis subsp. lactis strains tested, but in only one L. lactis subsp. cremoris strain. Given the obvious importance of the lactose-repression in cheese putrescine accumulation, it is advisable to consider the diversity of L. lactis in this sense and characterize consequently the starter cultures to select the safest strains.
乳酸乳球菌是乳制品工业中作为主要发酵剂使用最广泛的乳酸菌物种。然而，几株乳酸乳球菌通过胍丁胺脱亚氨酶（AGDI）途径产生生物胺腐胺。我们之前报道过乳酸乳球菌亚种cremoris GE2-14中的腐胺生物合成途径受葡萄糖而非乳糖的碳分解代谢阻遏（CCR）调控（Linares等人，2013年）。本研究表明，这两种糖都会抑制乳酸乳球菌亚种lactis T3/33（一种从西班牙手工奶酪中分离出的菌株）中的腐胺生物合成。此外，我们证明葡萄糖和乳糖都会抑制AGDI途径中aguBDAC分解代谢基因的转录活性。最后，在产腐胺的乳制品乳酸乳球菌菌株中进行的一项筛选确定，在所有测试的乳酸乳球菌亚种lactis菌株中，腐胺生物合成受乳糖抑制，但在仅一株乳酸乳球菌亚种cremoris菌株中是这样。鉴于乳糖抑制在奶酪腐胺积累中具有明显的重要性，从这个意义上讲，考虑乳酸乳球菌的多样性并相应地表征发酵剂培养物以选择最安全的菌株是明智的。
