Carrasco Purificación, Pérez-Ortín José E, del Olmo Marcel lí
Department de Bioquímica i Biologia Molecular, Facultat de Ciències Biològiques, Universitat de València, Spain.
Syst Appl Microbiol. 2003 Sep;26(3):471-9. doi: 10.1078/072320203322497518.
Nitrogen deficiency in musts is one of the causes of sluggish or stuck fermentations. In this work we propose that arginase activity determination can be useful for detecting nitrogen starvation early in vinification. CAR1 and YGP1 genes are not specifically induced under conditions of nitrogen starvation. However, a significant increase in the enzymatic activity of arginase, the product of the CAR1 gene, is detected in vinifications carried out with musts containing limiting amounts of nitrogen. Moreover, on adding ammonia to a nitrogen-deficient vinification, even at late stages, this enzymatic activity is repressed, and growth rate is restored simultaneously. We also investigate the role of ethanol toxicity in nitrogen starvation. The results suggest that ethanol produced during vinification or exogenously added up to 8% (v/v) concentration does not cause nitrogen starvation under the conditions tested because arginase activity is not increased.
葡萄汁中的氮缺乏是发酵迟缓或停滞的原因之一。在这项研究中，我们提出测定精氨酸酶活性有助于在酿酒早期检测氮饥饿。在氮饥饿条件下，CAR1和YGP1基因不会被特异性诱导。然而，在用含有限量氮的葡萄汁进行的酿酒过程中，检测到CAR1基因产物精氨酸酶的酶活性显著增加。此外，在氮缺乏的酿酒过程中添加氨，即使在后期，这种酶活性也会受到抑制，同时生长速率恢复。我们还研究了乙醇毒性在氮饥饿中的作用。结果表明，在测试条件下，酿酒过程中产生的乙醇或外源添加浓度高达8%（v/v）的乙醇不会导致氮饥饿，因为精氨酸酶活性没有增加。
