Kits and processes for removing contaminants from nucleic acids in environmental and biological samples

A method for removing a contaminant or inhibitor from a nucleic acid-comprising sample, wherein the contaminant or inhibitor inhibits the amplification or hybridization of the nucleic acid in the sample, or inhibits an enzymatic reaction utilizing the nucleic acid in the sample, the method comprising the steps of:

• (a) providing a reaction mixture comprising the sample, a chaotropic agent, ammonium acetate, and a detergent;
• (b) isolating the nucleic acid and remaining contaminants and inhibitors from the reaction mixture in a supernatant;
• and
• (c) contacting the nucleic acid supernantant with aluminum ammonium sulfate resulting in the further removal of the contaminant or the inhibitor from the supernatant.

A method for efficient separation by flocculation of a contaminant or inhibitor from a nucleic acid-comprising sample, wherein the contaminant or inhibitor inhibits the amplification or hybridization of the nucleic acid in the sample, or inhibits an enzymatic reaction utilizing the nucleic acid in the sample, the method comprising the steps of:

• (a) providing a reaction mixture comprising the sample, a chaotropic agent, ammonium acetate or an equivalent, and a detergent, wherein the presence of the chaotropic agent, the ammonium acetate or equivalent, and the detergent in the reaction mixture with the sample, results in the separation of the nucleic acid and the contaminant, the separation of the nucleic acid and the inhibitor, the separation of a protein present in the sample and the nucleic acid, the separation of a protein present in the sample and the inhibitor, the separation of a protein present in the sample and the contaminant, or any combination of the above, present in the sample;
• (b) isolating the nucleic acid and remaining contaminants and inhibitors from the reaction mixture in a supernatant;
• and
• (c) contacting the nucleic acid supernantant with a flocculant resulting in the further removal of the contaminant or the inhibitor from the supernatant.

A method for maximum recovery of a nucleic acid from a nucleic acid-comprising sample, the method comprising the steps of:

• (a) providing a reaction mixture comprising the sample, a chaotropic agent, ammonium acetate or an equivalent, and a detergent, wherein the presence of the chaotropic agent, the ammonium acetate or equivalent, and the detergent in the reaction mixture with the sample, results in the separation of the nucleic acid and the contaminant, the separation of the nucleic acid and the inhibitor, the separation of a protein present in the sample and the nucleic acid, the separation of a protein present in the sample and the inhibitor, the separation of a protein present in the sample and the contaminant, or any combination of the above, present in the sample;
• (b) isolating the nucleic acid and remaining contaminants and inhibitors from the reaction mixture in a supernatant;
• and
• (c) contacting the nucleic acid supernantant with a flocculant resulting in the further removal of the contaminant or the inhibitor from the supernatant;
• and
• (d) recovering the nucleic acid from the nucleic acid-comprising sample.

A method for post-isolation purification and/or amplification of a nucleic acid extracted from an environmental or a biological sample, wherein the isolated nucleic acid does not yield a detectable amplification product in an amplification reaction, and optionally the amplification reaction is a polymerase chain reaction (PCR), comprising the steps of:

• (a) providing a reaction mixture comprising the environmental or biological sample, a chaotropic agent, ammonium acetate or an equivalent, and a detergent,
• (b) isolating the nucleic acid and remaining contaminants and inhibitors from the reaction mixture in a supernatant;
• (c) contacting the nucleic acid supernantant with a flocculant resulting in the further removal of the contaminant or the inhibitor from the supernatant;
• and
• (d) purifying and/or amplifying the nucleic acid.