摘要:
为了筛选有抑菌活性的乳酸菌并分析其抑菌的物质基础,利用牛津杯琼脂扩散法,分析了19株从牧区风干肉制品中分离得到的肉源乳酸菌发酵上清液对大肠杆菌和金黄色葡萄球菌的抑菌能力,同时从中分别选取对大肠杆菌和金黄色葡萄球菌抑制能力有显著差异的乳酸菌各3株,对其上清液中的抑菌物质基础和抑菌能力影响因素进行了分析。结果表明19株乳酸菌中菌株F19对大肠杆菌的抑菌活性最强,抑菌圈直径为(15.07±0.55) mm,而F11发酵上清液对大肠杆菌完全没有抑制效果,菌株F16对金黄色葡萄球菌的抑菌活性最强,抑菌圈直径为(14.47±0.38) mm,而F6、F2发酵上清液对金黄色葡萄球菌完全没有抑制效果;抑菌的物质基础分析表明,酸性环境在抑菌过程中占主导地位,细菌素与过氧化氢发挥协同作用;对其发酵上清液进行不同pH以及不同温度处理后发现,其抑菌活性在pH<5.0时随pH的降低而显著增强(P<0.05),当pH分别升高至5.0、6.0、7.0时试验乳酸菌发酵上清液均不具有抑菌能力,F18发酵上清液分别在60、80、100、121 ℃热处理一定时间后其抑菌能力与对照组相比仍然无明显差异(P>0.05),F11发酵上清液在100 ℃热处理30 min后抑菌能力显著减弱(P<0.05),其余实验菌株发酵上清液温度达到60 ℃以上,抑菌能力随热处理温度提高而显著(P<0.05)下降。本研究发现了乳酸菌发酵上清液的抑菌效果具有特异性,抑菌物质主要是酸性物质,其次是细菌素和过氧化氢;抑菌能力受pH和温度影响,同时具有特异性。研究结果可为优质菌种资源开发提供理论指导与技术支持。
Abstract:
In order to screen lactic acid bacteria with inhibitory activity and analyze the inhibitory substance basis,the inhibitory ability of fermentation supernatant from 19 lactic acid bacteria,isolated from air dried meat products in pastoral areas,to E. coli and S. aureus were analyzed by Oxford cup agar diffusion method.Finally three of them with significant difference in inhibitory ability of E. coli and S. aureus were selected respectively to analyze the inhibitory substance basis and influence factors of inhibitory ability in its fermentation supernatant. The result showed that F19 strain had the strongest inhibitory activity to E. coli,and the diameter of the inhibitory circle was(15.07±0.55) mm,while the fermentation supernatant of F11 had no inhibitory effect on E. coli at all. The F16 had the strongest inhibitory activity to S. aureus,and the inhibitory circle diameter was(14.47±0.38) mm,while the fermentation supernatant of F6 and F2 had no inhibitory effect on S. aureus at all. According to the analysis of the inhibitory substance basis,acidic environment played a leading role in the process of bacteriostasis. Bacteriocins and hydrogen peroxide had a synergistic effect. The fermentation supernatant of the test strains was treated with different pH and temperature,and it was found that the inhibitory activity of the fermentation supernatant was significantly enhanced with the decreasing of pH when pH<5.0(P<0.05). When the pH value increased to 5.0,6.0 and 7.0,the experimental lactic acid bacteria fermentation supernatant had no inhibitory ability. After heat treatment at 60,80,100 and 121 ℃ for a certain time respectively,the inhibitory ability of F18 fermentation supernatant was still not significantly different from that of the control group(P>0.05).After heat treatment at 100 ℃ for 30 min,the inhibitory activity of the fermentation supernatant of F11 significantly decreased(P<0.05). When the treatment temperature of the fermentation supernatant of other experimental strains reached above 60 ℃,the inhibitory activity significantly decreased with the increase of heat treatment temperature(P<0.05). In conclusion,lactic acid bacteria fermentation supernatant had specific inhibitory effect,and the main bacteriostatic substances were acid substances,followed by bacteriocin and hydrogen peroxide.The bacteriostatic ability was affected by pH and temperature with specificity,which could provide theoretical guidance and technical support for the development of high quality strain resources.
百度学术
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