Vasileva-Tonkova Evgenia, Galabova Danka, Stoimenova Emilia, Lalchev Zdravko
Department of Microbial Biochemistry, Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria.
Microbiol Res. 2008;163(4):481-6. doi: 10.1016/j.micres.2006.07.015. Epub 2006 Sep 7.
Bacterial isolates from industrial wastewater were characterized according to probable modes of hexadecane uptake based on data for cell surface hydrophobicity, emulsifying activity, glycoside content and surface tension of cell-free culture medium. The results obtained suggested that both modes of biosurfactant-enhanced hexadecane uptake by bacterial strains take place, direct uptake and alkane transfer. The increase in cell surface hydrophobicity and glycoside production by the strains suggested the existence of biosurfactant-enhanced interfacial uptake of the alkane. Such mechanism is probably predominant for three isolates, Staphylococcus sp. HW-2, Streptococcus sp. HW-9 and Bacillus sp. HW-4. Secreted biosurfactants enhanced mainly alkane emulsification for most hydrophobic isolate Arthrobacter sp. HW-8, and micellar transfer for most hydrophilic isolate Streptococcus sp. HW-5. For other strains (67%) both mechanisms of biosurfactant-enhanced hexadecane uptake probably take place in similar degree, interfacial uptake and alkane emulsification. The results obtained could contribute to clarifying the natural relationships between the members of water ecosystem studied as well as will reveal potential producers of surface active compounds.
根据细胞表面疏水性、乳化活性、糖苷含量和无细胞培养基表面张力的数据，对工业废水中分离出的细菌进行了基于十六烷摄取可能模式的表征。所得结果表明，细菌菌株通过生物表面活性剂增强十六烷摄取的两种模式均会发生，即直接摄取和烷烃转移。菌株细胞表面疏水性和糖苷产量的增加表明存在生物表面活性剂增强的烷烃界面摄取。对于三种分离菌株，即葡萄球菌属HW - 2、链球菌属HW - 9和芽孢杆菌属HW - 4，这种机制可能占主导地位。对于疏水性最强的分离菌株节杆菌属HW - 8，分泌的生物表面活性剂主要增强烷烃乳化；对于亲水性最强的分离菌株链球菌属HW - 5，分泌的生物表面活性剂主要促进胶束转移。对于其他菌株（67%），生物表面活性剂增强十六烷摄取的两种机制，即界面摄取和烷烃乳化，可能以相似程度发生。所得结果有助于阐明所研究的水生态系统成员之间的自然关系，同时也将揭示表面活性化合物的潜在产生者。
