The undiluted DNA elute (1 µl) described in Figure 1 underwent PCR analysis with eubacterial primers. The results are displayed on an 0.8% TAE agarose gel. The DNeasy PowerSoil Kit was the only kit that yielded a PCR product for landfill samples (lanes 1 and 2), lake sediment (lane 6) and mulch topsoil (lane 9). High remaining humic acid content inhibited amplification for DNA isolated with kits from other manufacturers. DNA isolated with the DNeasy PowerSoil Kit had positive amplification in 100% of samples. Other supplier kits had positive amplification in 44% of samples.
The DNeasy PowerSoil Kit was used to isolate total genomic DNA from nine different sample types. The results were compared with those from soil DNA isolation kits from two other suppliers. All manufacturer’s protocols were followed. 15 µl of eluted genomic DNA was used per lane of a 0.8% TAE agarose gel.