Metagenome And Metatranscriptome Of Acid Mine Drainage From Fankou Lead-zinc Mine Tailing

The metabolic activities of microorganisms are central to the biogeochemicalcycles of elements in any ecosystem. Acid Mine Drainage (AMD) is mainly resultedfrom numbers of iron-and sulfur-oxidizing microorganisms whose metabolicactivities could accelerate the dissolution of sulfide minerals. A comprehensiveunderstanding of the biological function of the microbial community in acid minedrainage (AMD) is of great significance on bioremediation and bioleaching. While inorder to gain insights into the metabolic pathways of the whole microbial community,it need to be known clearly about the function of each members as well as thecommunity structure of it.Using a metagenomic approach to study microbial community in acid minedrainage from Fankou lead-zinc deposited mine, we reported11dominatingpopulations whose draft genomes were reconstructed, including7bacteria and4archaea. Most of them are uncultivated and these members represented nearly wholemicrobial community composition inside this acid mine drainage.Combined with a metatranscriptome approach which could unravel microbialcapabilities expressed in situ, we found that the whole microbial community had highgene expression in several basic metabolic pathways, such as amino acid metabolism, carbohydrate metabolism, nuclear acid metabolism and energy metabolism. It ismainly because in such oligotrophic habitat, microbes must consistently synthesizeorganic products, functional proteins and gain energy from sulfide mineral oxidation,all of which could support cell growth and activities. In addition, we found genesinvolved in responding to environmental stress, such as heavy metal, low pH andintracellular oxidative stresses had high expression acitivity that could banifitmicrobial survive.Based on metatranscriptome analysis, Archaea had low gene expression in basicmetabolic pathways and just had significant gene expression in some GeneticInformation Processing and some amino acid metabolism. Besides, it had a high geneexpression involved in pH-resistance which may results from stress in low pHenvironment.Lastly, we succeeded to predict and reconstruct the metabolic pathways of themost abundant population whcih belonged to class Betaproteobacteria (genusFerrovum). Besides, based on its strong gene expression on sulfur metabolism, weproposed that such microbe may have a specific role in acidification process of AMD.It uses ferrous and sulfur as electron donor to gain energy which lead to thedissolution of sulfide minerals. While along with decreasing pH value of AMD, thispopulation may be less representation.