A viscous sample can indicate incomplete sample lysis. Try using less of your sample and optimize bead beating conditions (duration, speed, time) to ensure samples are thoroughly lysed. After bead beating, pellet the cell debris before moving on. Adding more Genomic Lysis buffer to the lysate can help dilute and deproteinate the sample, making the sample less viscous and more suitable for DNA recovery.

Environmental samples often contain inhibitors such as polyphenolics, humic/fulvic acids, tannins, melanins, etc. that affect downstream applications such as PCR. Once the DNA is eluted off the binding column, the DNA is then passed through the Zymo-Spin III-HRC to remove the PCR inhibitors, and the DNA is then ready for downstream applications. The Zymo-Spin III-HRC does not bind DNA, it simply removes the PCR inhibitors. The Zymo-Spin III-HRC can be purchased separately as the OneStep PCR Inhibitor Kit (D6030).

Addition of beta-mercaptoethanol is recommended to enhance sample lysis, but can be substituted with dithiothreitol (DTT, final concentration of 10 mM). However, if bead beating is optimized and lysis is efficient, the addition of BME is not necessary and can be omitted.

No additional RNase A treatment is required when processing samples within kit capacity. The selective chemistry allows for binding of double stranded DNA to the column and for RNA to flow through.