Isolation, Screening And Identification Of Lead-resistance Lactic Acid Bacteria

Inner Mongolia is abundant in mineral resources but the process of exploitation and utilization always worsen the environmental pollution. The data showed that pollution index of Baotou tailing reservoir and Baiyuan Ebo mining area was 9 times higher than the background value,which seriously threaten the healthy and safety.Although the research of removal of heavy metals by biosorption process is one of the most popular research topics, the application of microorganisms are used as a biological adsorbent of heavy metals which can applied to the human body is still at an initial stage.Sixty two Lactic acid bacteria were collected from soil samples of Baotou tailing reservoir, Baiyuan Ebo mining area, then were isolated and screened. These strains were inoculated in medium with different concentrations of lead to explore the lead ions ability. The results showed that all the strains were lead tolerant but the tolerance ability were different. The repair capability of lead ions increased gradually with the extending of incubation time. The strains grown at 30℃ had a better repair capability of lead ions than the strains grown at 37℃.The isolated strain showed a stronger capability of repair when concentration of lead ions was 1200-9600mg/L. There were 13 strains including strain BY-Fa4, BG-5b3 and BG-8b2 could tolerant lead ions concentration of 7200mg/L, strain BY-Fal, BY-Fc2 and BG-6bl could grow in 8400mg/L lead ions concentration, and all mentioned strains had a strong lead ions ability.The isolated strains with high tolerance to lead was identified according to 16S rRNA gene sequence analysis as well as morphological features, physiological-biochemical analysis. The results showed that the strain BG-10al and BG-5b3 were identified as Pediococcus pentosaceus, the strain BG-6bl was Lactobacillus sakei, the strain BY-Fa5, BY-Ff3, BY-Fe21, BY-Fe3 and BG-8b2 were Lactobacillus pentosus, the strain BY-Fa2、 BY-Fa4 were Lactobacillus pentosus, the strain BY-Fal, BY-Fc2 and BY-Ff4 were Lactobacillus plantarum.