| 摘要: |
| 【目的】筛选高效实用的玉米赤霉烯酮（ZEN）降解菌株，并初步探究其降解机制及降解效果。【方法】以ZEN为唯一碳源，从发霉饲料和土壤样品中筛选菌株，通过形态学观察、16S rDNA测序分析对菌株进行鉴定；以培养时间为变量对菌株生长速率和ZEN降解率进行相关分析；通过测定菌株不同活性成分及失活处理后的ZEN降解率对降解活性物质进行初步分析定位；对比探究硫酸铵沉淀法（硫酸铵饱和度分别为30%，40%，50%，60%，70%和80%）和单宁 聚乙二醇法（单宁质量浓度分别为2，5，10，15和20 mg/mL；聚乙二醇质量浓度分别为6，8，10，12和14 mg/mL）对粗降解酶的提取效果；通过SDS PAGE凝胶电泳测定目标活性蛋白的分子质量，最后以菌株和粗酶液调节霉变玉米粉的水分质量分数，测定ZEN的降解效果。【结果】筛选得到试验菌株XJ-140，经鉴定为解淀粉芽孢杆菌（Bacillus amyloliquefaciens），该菌在培养24 h时可降解93.75%的ZEN（2 μg/mL）。菌株XJ 140以胞外酶降解ZEN为主，同时辅以细胞壁吸附。硫酸铵沉淀法（硫酸铵饱和度60%）和单宁-聚乙二醇法（最优单宁质量浓度为10 mg/mL，最优聚乙二醇质量浓度为10 mg/mL）提取粗降解酶的ZEN降解率分别为37.14%和51.49%，单宁-聚乙二醇法提取效果更优。初步推断目标活性蛋白的分子质量在61 ku或28 ku。此外，菌株XJ-140的发酵液和粗酶液均能够降解霉变玉米粉中的ZEN。【结论】筛选的菌株XJ-140通过胞外酶降解ZEN，实际应用中对ZEN污染的玉米粉有一定清除效果。 |
| 关键词: 玉米赤霉烯酮 解淀粉芽孢杆菌 降解酶 降解效果 |
| DOI：10.13207/j.cnki.jnwafu.2025.01.002 |
| 分类号: |
| 基金项目:河南省重点攻关项目（212102110157）；河南省重点研发与推广专项（科技攻关）（212102110174） |
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| Screening,identification and degradation efficacy evaluation of zearalenone degrading bacteria |
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XUE Linlin1, ZHANG Pengzhen1, YANG Xiaojin2, FAN Shouwu2, LI Wang1
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1.College of Animal Science and Technology,Henan University of Science and Technology,Luoyang,Henan 471023,China;2.Luoyang OKBK Biotechnology Co.,Ltd,Luoyang,Henan 471600,China
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| Abstract: |
| 【Objective】This study screened efficient and practical strains capable of degrading zearalenone (ZEN) and preliminarily investigated the degradation mechanism and effectiveness.【Method】Strains were screened from moldy feed and soil samples using ZEN as the sole carbon source and were identified by morphological observation and 16S rDNA genes equence analysis.The growth rate of strains and ZEN degradation rate were analyzed using time as a variable.The degradation active substances were preliminarily analyzed and localized through the determination of ZEN degradation rate in different active components and inactivated treatments.The extraction effects of crude degradation enzymes using ammonium sulfate (AS) precipitation (AS saturation of 30%,40%,50%,60%,70% and 80%) and tannin-polyethylene glycol method (tannin mass concentrations of 2,5,10,15 and 20 mg/mL and polyethylene glycol solution mass concentrations of 6,8,10,12 and 14 mg/mL) were compared.The molecular weights of target active proteins were determined by SDS-PAGE gel electrophoresis.Finally,the degradation effect of ZEN was determined by adjusting moisture mass fraction of mold-contaminated cornmeal with identified strains and crude enzyme solution.【Result】The screened test strain XJ-140 was identified as Bacillus amyloliquefaciens,which could degrade 93.75% of ZEN (2 μg/mL) within 24 hours.The strain XJ-140 mainly degraded ZEN with extracellular enzymes and was complemented by cell wall adsorption.The ZEN degradation rates of crude degradative enzymes extracted by 60% saturation of AS and tannin-polyethylene glycol method (optimal tannin concentration 10 mg/mL and optimal polyethylene glycol concentration 10 mg/mL) were 37.14% and 51.49%,respectively.The tannin-polyethylene glycol method of extraction was more favorable.The molecular weight of target active protein was preliminarily inferred to be 61 ku or 28 ku.Both the fermentation solution and crude enzyme solution of strain XJ-140 could degrade ZEN in mold-contaminated cornmeal.【Conclusion】The strain XJ-140 utilized extracellular enzymes to degrade ZEN and exhibited discernible efficacies in reducing ZEN contamination in practical applications involving mold-contaminated cornmeal. |
| Key words: zearalenone Bacillus amyloliquefaciens degradation enzyme degradation efficacy |
