荸荠贮藏期间2株腐败菌鉴定及其特性

Identification and characteristics of two spoilage bacteria from water chestnut during storage

为确定引起荸荠腐烂的细菌种类及其主要生物学特性,从腐烂的荸荠中分离到2株细菌,经16S RNA基因序列结果分析,确定其分别为木糖氧化无色杆菌(Achromobacter xylosoxidans)和产气肠杆菌(Enterobacter aero-genes)。对其生物学特性进行研究后发现,2株腐败菌生长速度较快;产气肠杆菌的耐酸、耐温、耐盐性较强,培养液初始p H 3. 5,培养温度45℃,或培养液中添加7. 5%的Na Cl,仍不能完全抑制其生长,而木糖氧化无色杆菌的耐酸、耐温、耐盐性则较差;此外,2株菌株对青霉素、红霉素、链霉素及氯霉素的抗性较强,最低抑制质量浓度均高于1 024μg/ml,对庆大霉素、万古霉素及四环素的最低抑制质量浓度均低于1 024μg/ml,且产气肠杆菌的耐受力强于木糖氧化无色杆菌。本研究结果为荸荠贮藏过程中的抗菌防腐提供了理论依据。

In order to learn about the species and characteristics of bacteria which cause the corruption of water chestnut,two bacteria were isolated from the rotten water chestnut,and then they were identified as Achromobacter xylosoxidans and Enterobacter aerogenes by 16S RNA sequence analysis.Results of biological characteristics showed that two strains of spoilage bacteria had fast growth rate.E.aerogenes grew slightly under the condition of initial pH3.5,culture temperature 45℃or 7.5%NaCl addition,while for A.xylosoxidans,the acid,temperature and NaCl endurance were weaker.In addition,two spoilage bacteria presented strong resistance to ampicillin,erythromycin,streptomycin and chloramphenicol,and the minimum inhibitory concentration(MIC)was higher than 1 024μg/ml.However,MIC for gentamicin,vancomycin and tetracycline was less than 1 024μg/ml,and E.aerogenes showed stronger resistance than A.xylosoxidans.These results provide theoretical basis for antimicrobial and antiseptic storage of water chestnut.