Screening For Biosurfactant-producing Bacterium And Preliminary Location Of Its Functional Gene

Biosurfactant is a high surface-active agent synthesized by plant, animal or microorganism, but at present the most biosurfactants come from the microorganism production.Compared with chemical surfactant, biosurfactant has environment compatibility, saying non-toxic, be completely degraded by microorganism, not create pollution to environment, good selectivity and few use level. Biosurfactant has been gradually applied in agriculture, architecture, food drink, industry clean, leather, papermaking, petroleum, environmental fields and so on. Many biosurfactants and their producing processes have been studied deeply and widely. However, so far few of biosurfactants have been industrialized for its low-yield and high costs. So it is the only way for the industrialization to extensively screen the strains and to analyze the producing processes and to study the relevance between the molecular structure and its function. Therefore, more biosurfactants of specific purpose and high function should be produced by the way of structural screening and computer simulating. And it is necessary to optimize the producing conditions and purification methods. Therefore, much integrated technology and other science such as simulation technology, nano-technology and bio-technology, is bound to the development of the overall trend.A large number of biosurfactant-producing strains have been reported. But the microbes on Earth are very rich so that less than 1% of microorganisms have been known. So there is still a lot of undiscovered species. In the paper, three biosurfactant-producing strains were screened from the organic pesticides activated sludge by designing filter medium. All of them are identified to belong to genera of Acinetobacter. From them, W2 with its surfactant has the best performance. So the factors for fermentation of surfactant were studied, and the fermentation condition was optimized initially..At the same time, the microbiology and molecular biotechnology has been developed, so that the process of microbial fermentation and the molecular mechanism of metabolic regulation have been deeply studies and are more and more clear. So more genetically engineered bacterial with high performance may be constructed with genetic analysis and molecular biotechnology, which is necessary for industrialization. In the paper the functional gene of Strain W2 was studied by the way of the elimination of bacterial plasmid and rapid detective technology. It was found that there is a big plasmid at least through electrophoresis test. The strains with plasmid can produce macrophages oil spot (that is to producing surfactant), but the strains with eliminated plasmid can not produce oil spot macrophages (that is to producing no surfactant). It is concluded that the functional gene is lactated among the plasmid.