Aspergillus luchuensis has been used to produce awamori, a distilled liquor, in Okinawa, Japan. Vanillin, derived from ferulic acid (FA) in rice grains, is one of the characteristic flavors in aged and matured awamori, known as kusu. Decarboxylation of FA leads to the production of 4-vinylguaiacol (4-VG), which is converted to vanillin by natural oxidization. However, the mechanism underlying FA conversion to 4-VG has remained unknown in awamori brewing. In our previous studies, we showed that phenolic acid decarboxylase from A. luchuensis (AlPAD) could catalyze the conversion of FA to 4-VG, and that AlPAD is functionally expressed during koji making (Maeda et al., J. Biosci. Bioeng., 126, 162–168, 2018). In this study, to understand the contribution of AlPAD to 4-VG production in awamori brewing, we created an alpad disruptant (Δalpad) and compared its 4-VG productivity to that of the wild-type strain. The amount of 4-VG in the distillate of moromi prepared with the wild-type strain showed a significant increase, proportional to the time required for koji making. In the Δalpad strain, the amount of 4-VG was very small and remained unchanged during the koji making. In an awamori brewing test using koji harvested 42–66 h after inoculation, the contribution of AlPAD to 4-VG production was in the range of 88–94 %. These results indicate that AlPAD plays a key role in 4-VG production during awamori brewing.

在日本冲绳，芦曲霉被用于生产泡盛酒，一种蒸馏酒。香兰素是从米粒中的阿魏酸（FA）衍生而来，是成熟和成熟的泡盛中的特色风味之一，被称为kusu。FA的脱羧会导致生成4-乙烯基愈创木酚（4-VG），并通过自然氧化将其转化为香兰素。然而，在泡盛酿造中，FA转化为4-VG的潜在机制仍然未知。在我们以前的研究中，我们显示了芦竹中的酚酸脱羧酶（AlPAD）可以催化FA转化为4-VG，而AlPAD在制曲过程中功能表达（Maeda等人，J。Biosci。Bioeng。，126，162–168，2018）。在这项研究中，为了了解泡盛酿造中AlPAD对4-VG生产的贡献，我们创建了alpad破坏剂（Δalpad），并将其4-VG生产率与野生型菌株进行了比较。用野生型菌株制备的moromi馏出物中的4-VG量显着增加，与制曲所需的时间成正比。在Δalpad菌株中，4-VG的量非常小，并且在曲制备过程中保持不变。在泡盛接种后42-66 h使用曲霉进行酿造试验，AlPAD对4-VG产量的贡献在88-94％范围内。这些结果表明，在泡盛酿造过程中，AlPAD在4-VG生产中起着关键作用。