Effects of Lys and His supplementations on the regulation of nitrogen metabolism in lager yeast
Effects of Lys and His supplementations on the regulation of nitrogen metabolism in lager yeast
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DOI：
10.1007/s00253-013-5137-x
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发表时间：
2013-10-01
影响因子：
5
通讯作者：
Zhao, Mouming
中科院分区：
文献类型：
--
作者：
Lei, Hongjie;Li, Huipin;Zhao, Mouming
在正常重力和高重力条件下，麦芽汁发酵力与赖氨酸和组氨酸的同化量呈显著正相关，表明赖氨酸和组氨酸是啤酒酿造过程中啤酒酵母的关键氨基酸。为了深入了解赖氨酸和组氨酸在氮素调控中的作用，本研究进一步研究了赖氨酸、组氨酸及其混合添加对啤酒酵母高浓发酵过程中发酵性能和氮代谢的影响。结果表明，赖氨酸和组氨酸的取代能促进酵母生长、麦芽汁发酵、乙醇产率和风味物质的形成。与氮代谢产物抑制（NCR）敏感基因（GAP 1和MEP 2）相比，添加赖氨酸显著上调了Ssy 1 p-Ptr 3 p-Ssy 5 p（SPS）调控基因（LYP 1、HIP 1、BAP 2和AGP 1），而添加组氨酸在指数生长期轻微激活了SPS调控基因，在整个发酵过程中显著抑制了NCR敏感基因。赖氨酸和组氨酸的添加增加了Glu和Phe的消耗，降低了Ser、Trp和Arg的消耗。此外，赖氨酸和组氨酸的添加对发酵性能的影响相似，并且在保持相同剂量的情况下，比它们的混合添加更有效。这些结果表明，赖氨酸和组氨酸是酵母氮代谢和发酵性能的重要氨基酸。
Significant positive correlations between wort fermentability and the assimilation of Lys and His under normal-gravity and high-gravity conditions indicated that Lys and His were the key amino acids for lager yeast during beer brewing. In order to obtain insight into the roles of Lys and His in nitrogen regulation, the influences of Lys, His and their mixture supplementations on the fermentation performance and nitrogen metabolism in lager yeast during high-gravity fermentation were further investigated in the present study. Results showed that Lys and His supplementations improved yeast growth, wort fermentability, ethanol yield and the formation of flavor volatiles. Lys supplementation up-regulated Ssy1p-Ptr3p-Ssy5p (SPS)-regulated genes (LYP1, HIP1, BAP2 and AGP1) dramatically compared to nitrogen catabolite repression (NCR)-sensitive genes (GAP1 and MEP2), whereas His supplementation activated SPS-regulated genes slightly in exponential phase, and repressed NCR-sensitive genes significantly throughout the fermentation. Lys and His supplementations increased the consumption of Glu and Phe, and decreased the consumption of Ser, Trp and Arg. Moreover, Lys and His supplementations exhibited similar effects on the fermentation performance, and were more effective than their mixture supplementation when the same dose was kept. These results demonstrate that both Lys and His are important amino acids for yeast nitrogen metabolism and fermentation performance.