Research On The Application Potential Of A New Coagulator For Purifying Of Bioleaching Microorganisms By Means Of Solid Plate Method

The separation and purification of bioleaching bacteria is the foundation for researches of application of bioleaching microorganisms and bioleaching mechanisms. At present, it is hard to acquire pure culture of bioleaching bacteria in the laboratory. The reasons are as follows:it has been hard to find a suitable solid medium for screening and purifying the bioleaching bacteria; the target strain can be polluted by other strain(s) any time. Therefore, the study of fast separation and purification of bioleaching bacteria is of theoretical and practical value.By means of reviewing a large number of references and basing on understanding the relevant physiological characteristics of the bioleaching bacteria, a suitable solid coagulator was selected, and was found that this new coagulator can confer the medium a good capacity of resistance to high temperature and high concentration of acid. This coagulator has the potential for screening the bacteria in bioleaching.A kind of solid plate was designed by using the new coagulator. By using the new solid plate, combining with water-dish cultivation method, a great number of bacterial colonies were successfully obtained, and the colonies of the bacteria are thermophilic bioleaching bacteria (Acidianus manzaensis), moderate thermophilic bioleaching bacteria (Ferroplasma thermophilum L1), mesophilic bioleaching bacteria (Acidithiobacillus ferrooxidans ATCC23270), respectively. Furthermore, the purified strains were also acquired by repeating this process. Yellow, rounded, and mucoid colonies were observed. The scanning electron microscope revealed that the bacteria in the colony adhering to the matrix surface of the solid plate by extracellular appendages. The analysis of ferrous oxidation activity of the strains re-cultivating in liquid medium shows that, the colonies possesssed ferrous oxidation activity.The new solid plate was used to screen mesophilic bioleaching bacteria from the natural acid mine drainage. The pure culture can use ferrous iron as energy substrate, and the ferrous oxidation rate can be as high as92%, indicating that the bacteria screened and purified from the natural acid mine drainage by this new solid plate possesssed ferrous oxidation activity.