Bacterial contaminants of fuel ethanol production
Bacterial contaminants of fuel ethanol production
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DOI：
10.1007/s10295-004-0159-0
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发表时间：
2004-10-01
影响因子：
3.4
通讯作者：
Leathers, TD
中科院分区：
文献类型：
--
作者：
Skinner, KA;Leathers, TD
细菌污染是商业燃料乙醇生产设施的持续问题。慢性和急性感染都令人担忧，因为细菌与生产乙醇的酵母竞争糖底物和微量营养素。在一轮污染中，乳酸水平往往会上升，这表明最常见的污染物是乳酸菌。然而，缺乏对商业玉米燃料乙醇设施的定量调查。在这项研究中，在生产线沿线的关键时间点和地点，在9个月的时间里从一个湿磨和两个干磨燃料乙醇设施收集了样品，并分离和鉴定了细菌污染物。湿磨设备的污染一直保持在10(6)个细菌/毫升。来自干磨设备的滴度变化较大，但经常达到10(8)/毫升。在湿磨操作中不使用抗生素。其中一个干磨设施只在酵母繁殖罐中添加抗生素，而第二个设施每隔4小时向发酵过程中添加抗生素。这两个投药程序似乎都不能可靠地减少总体污染，尽管第二个设施显示污染物之间的多样性较小。乳酸菌是三种植物中含量最丰富的菌株，平均为51株。湿法磨分离的菌株占总菌株的比例分别为38%和77%。尽管种群随着时间的推移而变化，但个别设施往往表现出特有的细菌图谱。表明发生了持续性的地方性感染。
Bacterial contamination is an ongoing problem for commercial fuel ethanol production facilities. Both chronic and acute infections are of concern, due to the fact that bacteria compete with the ethanol-producing yeast for sugar substrates and micronutrients. Lactic acid levels often rise during bouts of contamination, suggesting that the most common contaminants are lactic acid bacteria. However, quantitative surveys of commercial corn-based fuel ethanol facilities are lacking. For this study, samples were collected from one wet mill and two dry grind fuel ethanol facilities over a 9 month period at strategic time points and locations along the production lines, and bacterial contaminants were isolated and identified. Contamination in the wet mill facility consistently reached 10(6) bacteria/ml. Titers from dry grind facilities were more variable but often reached 10(8)/ml. Antibiotics were not used in the wet mill operation. One dry grind facility added antibiotic to the yeast propagation tank only, while the second facility dosed the fermentation with antibiotic every 4 h. Neither dosing procedure appeared to reliably reduce overall contamination, although the second facility showed less diversity among contaminants. Lactobacillus species were the most abundant isolates from all three plants, averaging 51. 38, and 77% of total isolates from the wet mill an the first and second dry grind facilities, respectively. Although populations varied over time, individual facilities tended to exhibit characteristic bacterial profiles. suggesting the occurrence of persistent endemic infections.