Investigation On Yeasts Diversity Of Acid Mine Environmentin Shizishan Sulfide Mine, Tongling, Anhui Province And Identification And Characterization Of Isolated Strain AMDX1-5 And AMDY2-5

Thirty-nine yeast strains were isolated from the samples of an acid mine drainge stream sediments and tailings in Shizishan sulfide mine, Tongling, using four selective media YE, Fe, FeT and FeS. The ITS and D1/D2 sequences were amplified from total DNA of yeast strains, then they were sequenced and analyzed. The phylogentic tree analysis with gene sequences of isolated yeast strains was carried out. Results showed that all of isolated yeast strains can be divided into four microbial communities: Rhodotorula sp, Rhodosporidium sp, Candida sp, Cryptococcus sp, but one of the yeast strains AMDX1-5, it’s closest strain is a strain of gungus Zymoseptoria brevis, but the morphology is totally different, so AMDX1-5 may be one new species.Strain AMDX1-5 (isolated from Xiangsigu sulfide mine, Tongling) and Strain AMDY2-5 (isolated from Shizishan sulfide mine, Tongling) were subjected to a taxonomic study.The features of strain AMDX1-5 in YPD media are as follows:the colony size is about 1 mm, the colony morphology is round, entire, raised, smooth, opaque, not sticky and the color is light pink, the cell morphology is oval, singly,with or without budding, no mycelium. The characters of strain AMDX1-5 were studied and optimal culture conditions of strain AMDX1-5 in YPD liquid media is as follows:pH 4.0, culture temperature 25 ℃, salinity 0%.The features of strain AMDY2-5 in YPD media are as follows:the colony size is 1.5-2mm, the colony morphology is round, entire, raised, smooth, opaque, thick and the color is white, the cell morphologt is round, singly,with or without budding, no mycelium. The characters of strain AMDY2-5 were studied and optimal culture conditions of strain AMDY2-5 in YPD liquid media is as follows:pH 4.0, culture temperature 25 ℃, salinity 0%.The acid resistance of Strain AMDX1-5 and Strain AMDY2-5 were studied. The short time acid stress shows that Strain AMDX1-5 has a strong acid resistance in the early stage of acid stress, but the acid resistance decreased gradually with the time extension. Strain AMDY2-5 has a weak acid resistance in the early stage of acid stress, but the acid resistance increased gradually. The growth of strain AMDX1-5 and strain AMDY2-5 in the YPD media with pH 2 and pH 4 shows that, the biomass of strain AMDX1-5 in pH2 is always lower than the biomass in pH 4. The biomass of strain AMDY2-5 in pH2 is significantly lower than the biomass in pH 4, but the growth rate is almost the same in the after days. Intracellular pH experiment shows that, strain AMDX1-5 has a poor ability to regulate the intracellular pH, its intracellular pH is neutral only in the YPD media with pH 3.0,4.0,5.0 and 6.0, and the intracellular pH is acidic with pH 2.0,2.5,7.0 and 8.0. But strain AMDY2-5 has a strong ability to regulate the intracellular pH, its intracellular pH is always neutral in the YPD media with pH 2.0-8.0.