Formation of Guaiacol by Spoilage Bacteria from Vanillic Acid, a Product of Rice Koji Cultivation, in Japanese Sake Brewing

Abstract

The formation of guaiacol, a potent phenolic off-odor compound in the Japanese sake brewing process, was investigated. Eight rice koji samples were analyzed, and one contained guaiacol and 4-vinylguaiacol (4-VG) at extraordinarily high levels: 374 and 2433 μg/kg dry mass koji, respectively. All samples contained ferulic and vanillic acids at concentrations of mg/kg dry mass koji. Guaiacol forming microorganisms were isolated from four rice koji samples. They were identified as Bacillus subtilis, B. amyloliquefaciens/subtilis, and Staphylococcus gallinarum using 16S rRNA gene sequence. These spoilage bacteria convert vanillic acid to guaiacol and ferulic acid to 4-VG. However, they convert very little ferulic acid or 4-VG to guaiacol. Nine strains of koji fungi tested produced vanillic acid at the mg/kg dry mass koji level after cultivation. These results indicated that spoilage bacteria form guaiacol from vanillic acid, which is a product of koji cultivation in the sake brewing process.

Isolation and characterization of Lignin-derived monomer degraders under acidic conditions from tropical peatland

“…Different theories exist in the literature regarding vanillin regarding some of the degradation products after conversion from vanillic acid to protocatechuic acid (Nishimura et al, 2018), while another found is guaiacol (Fig. S6), as reported by previous research (Álvarez-Rodríguez et al, 2003;Ito et al, 2016;Witthuhn et al, 2012). The current study found that metabolite production of strains S38 and S46 differs from previous research, as protocatechuic acid was not detected (Fig.…”

Multiplexed Paper Microfluidics for Titration and Detection of Ingredients in Beverages

“…Another biochemical product guaiacol found in spoiled fruit juices was also identified in a separate test. Guaiacol is a non-pathogenic chemical that is produced by the alicyclobacillus bacterial strains found in spoiled or tainted fruit juices [34]. In presence of guaiacol, the hydrogen peroxide and peroxidase reacted to form tetra guaiacol a visible brown colored complex (Figure 4b).…”

Microbial Community Affects Daqu Quality and the Production of Ethanol and Flavor Compounds in Baijiu Fermentation

“…The relative abundances of amylolytic microbes including Bacillus licheniformis, Lichtheimia ramosa, and Saccharomycopsis fibuligera were much higher in the QD than in the ID fermentation at the beginning (Figure 5c,d; Table S4), resulting in much more efficient hydrolyzation and saccharification of starch in the QD fermentation set, as indicated by its remarkably higher moisture content (Figure 6b). Contrarily, the ID fermentation set had a higher relative abundance of Bacillus subtilis and Staphylococcus gallinarum at the beginning, which are responsible for the ropiness in bread spoilage and the formation of guaiacol (an off-odor compound) in Japanese sake brewing [57,58]. These bacteria probably also negatively affect Baijiu fermentation.…”