Lactic acid bacteria (LAB) constitute a diverse group of Gram positive obligately fermentative microorganisms which include both beneficial and pathogenic strains. LAB generally have complex nutritional requirements and therefore they are usually associated with nutrient-rich environments such as animal bodies, plants and foodstuffs. Amino acids represent an important resource for LAB and their utilization serves a number of physiological roles such as intracellular pH control, generation of metabolic energy or redox power, and resistance to stress. As a consequence, the regulation of amino acid catabolism involves a wide set of both general and specific regulators and shows significant differences among LAB. Moreover, due to their fermentative metabolism, LAB amino acid catabolic pathways in some cases differ significantly from those described in best studied prokaryotic model organisms such as Escherichia coli or Bacillus subtilis. Thus, LAB amino acid catabolism constitutes an interesting case for the study of metabolic pathways. Furthermore, LAB are involved in the production of a great variety of fermented products so that the products of amino acid catabolism are also relevant for the safety and the quality of fermented products.

中文翻译：

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乳酸菌的氨基酸分解代谢途径。

乳酸菌（LAB）构成了多种革兰氏阳性专性发酵微生物，包括有益菌和致病菌。乳酸菌一般具有复杂的营养要求，因此通常与诸如动物体，植物和食品等营养丰富的环境有关。氨基酸是LAB的重要资源，其利用具有许多生理作用，例如细胞内pH值控制，代谢能或氧化还原能力的产生以及对压力的抵抗力。结果，氨基酸分解代谢的调节涉及广泛的一般和特异性调节剂，并且在LAB之间显示出显着差异。而且，由于它们的发酵代谢，在某些情况下，LAB氨基酸的分解代谢途径与在最佳研究的原核模型生物（如大肠杆菌或枯草芽孢杆菌）中描述的途径明显不同。因此，LAB氨基酸分解代谢构成了代谢途径研究的有趣案例。此外，LAB参与了多种发酵产品的生产，因此氨基酸分解代谢的产物也与发酵产品的安全性和质量有关。