一株栖盐田菌Salinicola sp.W1的柴油降解特性研究

结合Plackett-Burman设计与响应面法,以柴油降解率为响应值,对一株栖盐田菌(Salinicola sp.)W1的柴油降解条件进行了优化。Plackett-Burman试验结果显示,Fe SO4浓度、NH4NO3浓度和转速是影响柴油降解的显著因素。利用响应面法对3个因素进行了优化,确定Salinicola sp.W1降解柴油的最佳条件是Fe SO4浓度为0.1 mg/L,NH4NO3浓度为0.7 g/L,转速为118 r/min。在最佳条件下,柴油的最大降解率可达95.2%。该菌株有望应用于高盐环境中柴油污染的微生物修复。     

Identification of <Emphasis Type="Italic">N</Emphasis> −3-hydroxyoctanoyl-homoserine lactone production in <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis> 5064, pathogenic to broccoli,and controlling biosurfactant production by quorum sensing

Quorum sensing controls a number of key processes in growth, reproduction and virulence of many gram-negative bacteria via signalling molecules or autoinducers. It can control, for instance, the production of pectic enzymes which are virulence factors in disease. Pseudomonas fluorescens 5064 produces biosurfactants which are important for bacterial establishment on the plant surface prior to causing disease in broccoli. The aim of this paper was to determine if biosurfactant production in this bacterium is controlled via quorum sensing. To do this, 35 surfactant-minus Tn5 mutants of P. fluorescens 5064 were screened for their abilities to produce a quorum sensing signal. Six of these biosurfactant-deficient mutants showed a large reduction in quorum sensing signal production and varied in their abilities to cause disease. In one mutant, 6423, which contains a single Tn5 insertion, the production of the signal was almost eliminated. Synthetic quorum sensing signal and quorum sensing signal extracted from wild type P. fluorescens 5064 restored biosurfactant production by addition to the culture in mutant 6423. The quorum sensing signal in wild type P. fluorescens 5064 was identified by high pressure liquid chromatography and mass spectrometry as N -3-hydroxyoctanoyl-homoserine lactone.     

生物表面活性剂研究进展

指出了微生物产生的生物表面活性剂是一类天然两亲化合物生物,含有亲水基、疏水基结构,是一类绿色表面活性剂,具有高表面活性、高抗碱、高抗盐、无污染等特点,对其在医药行业、农业、化学工业、食品工业等领域的研究进展进行了论述。     

产生物表面活性剂石油降解菌Bacillus BS-8的生物学特性

研究石油降解菌BS-8(Bacillus sp.)的生长特性及影响其产生物表面活性剂的因素。通过测定BS-8发酵液的OD600 nm、表面张力、排油圈直径推测其生物表面活性剂的产生方式;考察了碳源、氮源、温度、p H、Na Cl浓度对其产生物表面活性剂的影响。结果表明,菌株BS-8生物的表面活性剂产生方式为生长相关型,发酵液的表面张力随菌体数量的增加而降低,排油圈直径与发酵液中表面活性剂含量呈正相关;菌株BS-8高产生物表面活性剂的碳源、氮源分别为葡萄糖、酵母膏,最适培养温度为30℃,最适p H7.0,最适Na Cl浓度为20 g/kg。