Application of soil pretreatments and AlNH4(SO4)2 in DNA extraction from soils contaminated with heavy metals

Abstract:

[Objective] The aim of this study was to obtain DNA with high purity, high yield and good integrity from the soil, for the analysis of the microbial diversity of heavy metal contaminated soil. [Methods] Accompanied by different soil pretreatments, AlNH4(SO4)2 was added in the DNA extraction buffer to analyze the yield, purity and integrity of the total DNA extracted from the soil. [Results] The DNA fragments extracted from the four different methods, TENP-AlNH4(SO4)2, ABG-AlNH4(SO4)2, Wash-AlNH4(SO4)2 and Reagent Kit, were all intact, and the sizes of them were all about 23 kb. The Wash-AlNH4(SO4)2 method gave the purest DNA with 2.13 at A260/A230 and 1.62 at A260/A280, while the yield from ABG-AlNH4(SO4)2 method was the highest with 1 010 μg DNA per gram soil. Both methods could provide DNA with sufficient purity and concentration for the following molecular experiments such as PCR. Through the amplification of 16S rRNA gene from the extracted soil DNA, PCR inhibitors in the soil could be efficiently removed by AlNH4(SO4)2 with appropriate concentrations. [Conclusion] By combining soil pretreatment and utilization of AlNH4(SO4)2, we obtained the desired total DNA from the soil contaminated with heavy metals.