豆豉中抗氧化芽孢杆菌的多样性分析和鉴定

Diversity analysis and identification of antioxidantive Bacillus spp.

从豆豉中分离筛选具有抗氧化能力的芽孢杆菌菌株，以豆粕为原料，以抗氧化性测试为筛选体系，筛选优良菌株并鉴定，了解菌株的抗氧化特性并为功能性成分的开发提供菌株资源。对菌株发酵豆粕上清液，使用DPPH·清除率作为初筛方法获得12株菌株，其清除率在86．2％～96．6％，使用·OH清除率等6种抗氧化评价方法进行复筛并测定多肽浓度，结果显示各抗氧化性测试方法间相关性不明显，仅有总抗氧化力与·OH清除率显著正相关，与·O2^-清除率极显著正相关。多肽浓度与各抗氧化性测试方法间无显著正相关，与脂质过氧化抑制率呈极显著负相关，提示12株菌株产生的抗氧化成分在类型和机理可能存在较高的多样性。将菌株发酵上清液密封后在50℃保存14d，抗氧化力均呈下降趋势，HFBL261菌株抗氧化力残留最高，对其表型形状和16S rDNA序列进行测定，鉴定为Bacillus subtilis。

The spore-forming strains were isolated form Douchi samples and screened for producing antioxidantive ingredient by using several antioxidant assay methods. Using DPPH radical scavenging activity of fermented soybean meal supernate as initial screening index, twelve strains with the DPPH radical scavenging rate of 86.2% -96.6% were selected. Six antioxidant assays including hydroxide radical scavenging method were used for rescreening. The peptide concentration of supernate was measured. The results of rescreening showed low correlation value among different antioxidant assay methods. There were significant linear positive correlations between total-antioxidant-capacity and hydroxide radical scavenging, and between total-antioxidant-capacity and superoxide anion radical scavenging. The peptide concentration didn＇ t show any significant positive correlation with the results of antioxidant assays, and showed significant negative correlation with inhibition rate of lipid peroxidation. It prompted the diversity in the type and mechanism of antioxidants produced by twelve strains. The selected strain, HFBL261, was identified as Bacillus subtilis through phenotype and 16S rDNA sequencing.