Barthelmebs L, Divies C, Cavin J F
Laboratoire de Microbiologie UMR-INRA, ENSBANA, Université de Bourgogne, Dijon, France.
Appl Environ Microbiol. 2000 Aug;66(8):3368-75. doi: 10.1128/AEM.66.8.3368-3375.2000.
Lactobacillus plantarum NC8 contains a pdc gene coding for p-coumaric acid decarboxylase activity (PDC). A food grade mutant, designated LPD1, in which the chromosomal pdc gene was replaced with the deleted pdc gene copy, was obtained by a two-step homologous recombination process using an unstable replicative vector. The LPD1 mutant strain remained able to weakly metabolize p-coumaric and ferulic acids into vinyl derivatives or into substituted phenyl propionic acids. We have shown that L. plantarum has a second acid phenol decarboxylase enzyme, better induced with ferulic acid than with p-coumaric acid, which also displays inducible acid phenol reductase activity that is mostly active when glucose is added. Those two enzymatic activities are in competition for p-coumaric and ferulic acid degradation, and the ratio of the corresponding derivatives depends on induction conditions. Moreover, PDC appeared to decarboxylate ferulic acid in vitro with a specific activity of about 10 nmol. min(-1). mg(-1) in the presence of ammonium sulfate. Finally, PDC activity was shown to confer a selective advantage on LPNC8 grown in acidic media supplemented with p-coumaric acid, compared to the LPD1 mutant devoid of PDC activity.
植物乳杆菌NC8含有一个编码对香豆酸脱羧酶活性（PDC）的pdc基因。通过使用不稳定复制载体的两步同源重组过程，获得了一种食品级突变体，命名为LPD1，其中染色体pdc基因被缺失的pdc基因拷贝所取代。LPD1突变菌株仍能够将对香豆酸和阿魏酸微弱地代谢为乙烯基衍生物或取代的苯丙酸。我们已经表明，植物乳杆菌具有第二种酸性酚脱羧酶，与对香豆酸相比，阿魏酸对其诱导作用更强，该酶还表现出可诱导的酸性酚还原酶活性，在添加葡萄糖时活性最强。这两种酶活性在对香豆酸和阿魏酸降解过程中相互竞争，相应衍生物的比例取决于诱导条件。此外，在硫酸铵存在的情况下，PDC在体外似乎能将阿魏酸脱羧，比活性约为10 nmol·min⁻¹·mg⁻¹。最后，与缺乏PDC活性的LPD1突变体相比，PDC活性显示出在添加对香豆酸的酸性培养基中生长的LPNC8具有选择性优势。
