Płaza Grazyna A, Ulfig Krzysztof, Brigmon Robin L
Institute for Ecology of Industrial Areas, 40-844 Katowice, Poland.
Pol J Microbiol. 2005;54(2):161-7.
Two bacterial strains identified as Ralstonia picketti (BP 20) and Alcaligenes piechaudii (CZOR L-1B) were isolated from petroleum hydrocarbon-contaminated soil following bioremediation treatment. The surface active properties, e.g. surface tension, emulsification and foamability of their culture filtrates were evaluated. Bacterial cell-surface hydrophobicity (BAH) as measured by analyzing cell affinity towards aliphatic and aromatic compounds was also determinated. The bacteria grew in liquid cultures containing 1% (v/v) of crude oil as carbon and energy source at 30 degrees C under aerobic conditions. The surface tensions were reduced to 61 mN/m and 55 mN/m by Ralstonia picketti and Alcaligenes piechaudii, respectively. The emulsification index (EI24) was almost 100% for all tested compounds except diesel oil. The stability of the emulsions was deteminated at 4 degrees C, 45 degrees C and 65 degrees C. The emulsions were stable at 4 degrees C. Ralstonia picketti was better foam inducer (FV = 50 ml) compared to Alcaligenes piechaudii (FV = 10 ml). The BAH measurements revealed higher adhesion of Alcaligenes piechaudii cells towards different hydrocarbons compared to Ralstonia picketti cells. The strains were found to have a surface hydrophobicity in the following order: aliphatic hydrocarbons, BTEX, and PAHs. The ability to adhere to bulk hydrocarbon is mostly a characteristic of hydrocarbon-degrading bacteria. The strains were found to be better emulsifiers than surface tension reducers. They produce water-soluble extracellular bioemulsifiers. Both bacterial isolates have good properties to use them, mainly in the petroleum industry, e.g. in enhanced oil recovery and in bioremediation processes-primarily due to their emulsification property, i.e. emulsion forming and stabilizing capacity.
从经过生物修复处理的石油烃污染土壤中分离出两株细菌菌株，分别鉴定为皮氏罗尔斯通氏菌（BP 20）和皮氏产碱菌（CZOR L-1B）。对其培养滤液的表面活性特性，如表面张力、乳化和起泡性进行了评估。还通过分析细胞对脂肪族和芳香族化合物的亲和力来测定细菌细胞表面疏水性（BAH）。这些细菌在有氧条件下，于30℃的含1%（v/v）原油作为碳源和能源的液体培养基中生长。皮氏罗尔斯通氏菌和皮氏产碱菌分别将表面张力降低到61 mN/m和55 mN/m。除柴油外，所有测试化合物的乳化指数（EI24）几乎为100%。在4℃、45℃和65℃下测定乳液的稳定性。乳液在4℃时稳定。与皮氏产碱菌（FV = 10 ml）相比，皮氏罗尔斯通氏菌是更好的泡沫诱导剂（FV = 50 ml）。BAH测量结果显示，与皮氏罗尔斯通氏菌细胞相比，皮氏产碱菌细胞对不同烃类的粘附性更高。发现这些菌株的表面疏水性顺序如下：脂肪族烃、BTEX和多环芳烃。附着于大量烃类的能力主要是烃降解细菌的一个特征。发现这些菌株作为乳化剂比表面张力降低剂更好。它们产生水溶性细胞外生物乳化剂。这两种细菌分离株都具有良好的特性，主要可用于石油工业，例如提高石油采收率和生物修复过程——主要是由于它们的乳化特性，即形成乳液和稳定乳液的能力。
