大红浙醋醋酸菌分离及其产酸关键氨基酸分析

该研究首先采用钙透明圈法从大红浙醋中分离筛选醋酸菌，并通过分子生物学技术对其进行菌种鉴定；然后研究10种氮源对巴氏醋酸杆菌的生长及产酸量的影响，并对10种氮源组分进行定性和定量分析，得出产酸代谢的关键氨基酸；最后挑出10种氨基酸进行验证。结果表明，分离筛选得到一株产酸菌株，编号为SHQ-A，经鉴定为巴氏醋酸杆菌（Acetobacter pasteurianus）。该菌株利用10种氮源发酵的产酸量在8.8～34.5 g/L范围内，且以酵母抽提物为氮源的产酸量明显高于蛋白胨。当缺少丙氨酸和精氨酸时，产酸量仅为18.0 g/L和19.2 g/L，分别低于空白组62.5%和60%，表明丙氨酸和精氨酸是产酸代谢的关键积极氨基酸；当缺少脯氨酸时，产酸量为61.2 g/L，高于空白组27.1%，表明脯氨酸是产酸代谢的关键消极氨基酸。

Isolation of acetic acid bacteria in red vinegar and analysis of key amino acids for acid production

Acetic acid bacteria were isolated from red vinegar by calcium transparent circle method,and the strains were identified by molecular biology technology.Then,the effects of 10 nitrogen sources on the growth and acid production of Acetobacter pasteurianus were studied,the composition of 10 nitrogen sources were analyzed qualitatively and quantitatively,and the key amino acids of acid metabolism were obtained.Finally,10 key amino acids were selected for verification.The results showed that an acid-producing strain was isolated and screened,numbered as SHQ-A,and was identified as Acetobacter pasteurianus.With fermentation of 10 kinds of nitrogen sources,the acid production of A.pasteurianus was in the range of 8.8-34.5 g/L,and the acid production of yeast extract as the nitrogen source was significantly higher than that of peptone.In the absence of alanine and arginine,the acid production of A.pasteurianus was only 18.0 g/L and 19.2 g/L,which were 62.5%and 60%lower than the control group,indicating that alanine and arginine were the key positive amino acids for acid production and metabolism.In the absence of proline,the acid production was 61.2 g/L,which was 27.1%higher than the control group,indicating that proline was the key negative amino acid for acid production metabolism.