热带海水中生物表面活性剂生产菌的筛选及特性研究

Screening and characterization of the bacterium producing biosurfactant in the tropical seawater

为评估生物表面活性剂生产菌对石油烃降解菌的辅助效应,从热带近海海域石油烃污染水样中筛选出一株生物表面活性剂生产菌BSM-301,通过生理生化试验和16S r DNA序列分析,确定该菌为微球菌属（Micrococcus sp.）,利用薄层色谱法和傅里叶变换红外光谱法初步确定其产物为脂肽类生物表面活性剂。以菌株发酵液的表面张力值为评价指标,对其生活条件进行优化,并进行海水环境条件下的石油烃辅助降解试验。结果表明,该菌株最佳碳源为葡萄糖,最适初始p H值为7.5,最适培养温度为30℃,添加后石油烃降解率比两种降解菌SJDQ-112和SJDQ-1122单独作用分别提高了64.9%和86.2%。试验正向辅助效果较为明显,为进一步研究海水中石油污染的生物修复提供了理论依据。

In order to study the auxiliary effect of biosurfactantproducing bacteria on the petroleum hydrocarbon degrading bacteria,the paper has managed to screen out a biosurfactant-producing bacterium,known as BSM-301,from the petroleum-hydrocarbon-contaminated waters in the tropical offshore marine waters.In proceeding with our research,we have first of all examined and confirmed that the products of the strain contain biosurfactant components through the oil plate degradation test and the oil drain test so as to identify and determine that the products preliminarily belong to the lipopeptide surfactants through TLC and FT-IR tests. And,then,the physiological and biochemical tests and 16 S r DNA sequence test help to identify and determine BSM-301 as Micrococcus sp. Taking the surface tension value of the strain fermentation broth as an evaluation index,its living conditions can be optimized by the parameters through the study of the utilization capacity of the 4 carbon sources,that is,the sucrose,the glucose,the crude oil and the diesel oil. Furthermore,the adaptation range of p H value and the temperature,in addition to its auxiliary effects,have been examined and assessed in the marine water environment,through the integrated degradation tests of the strain and the petroleum hydrocarbon degrading bacteria. The results of the aforementioned tests and identification prove that,for the bacteria BSM-301,the optimum carbon source should be the glucose,though it has also had a nice performance if the carbon source were to be petroleum hydrocarbon with the optimum p H value（ initial environmental） being 7. 5,in a suitable range of7. 0-7. 5,whereas the optimum culture temperature is 30 ℃,in a suitable temperature range being 25-30 ℃. On the other hand,the oil degradation rates of the 2 degrading bacteria SJDQ-112, SJDQ-1122 tend to get increased by 64. 9% and86. 2%,respectively,with the positive auxiliary effect of BSM-301 being more remarkable. All the above mentioned study results demonstrate that the strain known as BSM-301 enjoys fine adaptability for the petroleum-hydrocarbon-contaminated marine environment and can be oriented for good use of petroleum hydrocarbon pollutant as its carbon source. And,simultaneously,p H value,the temperature and the inorganic salt nutrient conditions of the tropical marine areas can all help to provide a perfect habitat for the strain.