Isolation and identification of four strains of Leptospirillum ferriphilum from four acid mine drainage sites and their roles in bioleaching of pyrite

摘要

Abstract; In this study, four bacterial strains - DWT, SLS, YTW and ZBY were isolated from four different acid mine drainage ( AMD) sites using serial dilution method. Their morphological and physiological characteristics, phylogenetic relationship and ability in bioleaching of pyrite were studied respectively. Physiological examination showed that the optimal temperature for the growth of strains DWT, SLS, YTW and ZBY were 351, 351, 351 , 40° C , respectively; and the optimal pH for their growth were 1. 5 , 1. 8 , 2. 1 and 1.8, respectively. The results of phylogenetic analyses based on 16S rRNA and gyrB gene suggested that all the isolated strains should be affiliated with the species of Leptospirillum ferriphilum. Bioleaching experiment showed that all the strains could oxidize pyrite efficiently, and the iron extraction rates achieved a high level ranging from 80% to 93% after 18 days.