Optimization of DNA extraction of enriched iron-reducing bacteria from tropical freshwater stream sediment for metagenomic analysis

Iron reducing bacteria (IRB) promote the reduction of iron oxides in anoxic soils and sediments and play a major role in the cycling of these metals and other elements such as organic carbon in aqueous environments. Previous studies investigating the IRB focused on cultivable microbial composition. The composition of IRB can be varied greatly in the environment and some of them cannot be detected by the conventional method. Thus, there were limited researches about IRB distribution in Malaysia tropical river environment. The DNA from enrichment was extracted for metagenomic analysis. Enrichment incubations were conducted by using different concentration of electron donors. Then, the Fe (II) reduction concentration on hydrous ferrous oxide (HFO) was investigated. In general, higher concentrations of electron donors resulted the high production of Fe2+. The survival of IRB in different concentration of Fe (II) was believed to be associated in determining the microbial composition and microbial shift in the enrichment and environment during reduction process.