Q1: My lysate seems viscous. What is causing this to happen? How can I fix this?
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.
Q2: Are there any tips in optimzing bead beating conditions?
We have validated our kits with both high-speed homgenizers and low-speed disruptors. We highly recommend users to optimize their bead beating conditions for their own instruments. We recommend using a 2 ml-tube adapter to ensure that the bead beating is efficent (do not use adapters made of foam). For high-speed homogenizers, we recommend a total of 5 mins bead beating (1 min interval at 6.5 m/s with 5 mins rest, repeat 5 times). For low-speed cell disruptors, we recommend 30 mins at max speed.
Q3: What is the purpose of Zymo-Spin III-HRC step?
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).
Q4: Is it necessary to add beta-mercaptoethanol? Can this step be substituted or omitted?
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.
Q5: When can an RNase A treatment be implemented in the protocol?
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.
