Abstract:The producing ability of acetoin, polyphenol, ester and non-volatile acid of 54 Bacillus strains isolated from cupei of Shanxi aged vinegar was determined. Two excellent strains of Bacillus amyloliquefaciens 1539 and Bacillus subtilis 803 were screened, with higher polyphenols (750.96 μg/mL), non-volatile acids (2.93 g/L), ester (0.92 mg/mL) and acetoin (9.63 g/100 mL) producing ability. The results showed that when the Bacillus amyloliquefaciens 1539 and Bacillus subtilis 803 were co-cultured at 1 ∶ 10, the production of acetoin, polyphenols, total ester and non-volatile acid were significantly higher than those of pure culture. The main non-volatile acids of vinegar like oxalic acid, pyruvate, tartaric acid and lactic acid were increased by 89.78%, 88.32%, 22.92% and 32.98%, respectively. Additionally, the variety and content of volatile aroma components were also significantly increased. When the combination of Bacillus strains (Bacillus amyloliquefaciens 1539 ∶ Bacillus subtilis 803 was 1 ∶ 10, V ∶ V) were co-cultured with Acetobacter pasteurianus 33 and Lactobacillus plantarum 19, the contents of volatile aroma components such as ethyl acetate, ethyl isovalerate, 1-octene-3-ol, furfural were distinctly increased. This study provided important data support for the development of the mixed starter of Shanxi aged vinegar fermentation.