Dear Yogesh,

You can use PVP or CTAB in the lysis buffer or else you may use them in the agarose gel itself so that they precipitate the humic acid contaminants thus leaving your metagenomic DNA pure and cloneable.

Go through this article

http://www.sciencedirect.com/science/article/pii/S0734975008000839

Dear Yogesh,

Humic acids are rich in aromatic rings and aliphatic chains so my suggestion is to extract your genomic DNA solution with one volume of phenol:chloroform:isoamylic alcohol (15:14:1 vol.). Just add one volume of the mixture, vortex for 1 minute, then centrifuge and take up the aqueous phase which should contain unmodified DNA and no more humic acids that will be partly solubilized in the organic phase and partly kept at the organic-aqueous interface.

Then precipitate your DNA and .. that should be done !

Best regards,

Prof Philippe Urban

Thanks..

We also had lots of difficulties to remove humic acids. We could finally get rid of it by  using a PEG/NaCl precipitation, during extraction , in this publication you will be able to find our protocol

http://link.springer.com/article/10.1007%2Fs10295-012-1217-7

(if you don't have access to it, I can send it to you privately ;-))

If you have any question about the protocole don't hesistate to aks.

Dear Yogesh,

The Mo Bio Powersoil DNA extraction kit is an excellent method of extracting DNA - and states that it 'eliminates 100% of humic substances and other PCR inhibitors'. Here is the link to information:

http://www.mobio.com/soil-dna-isolation/powersoil-dna-isolation-kit.html 

They have distributers all over the world - the distributer in  India is:

Genaxy Scientific Pvt. Ltd

Corporate Office

155-156, C-Block, Community Centre,

Plot 32 to 57. Behind Janak Cinema,

Janak Puri, New Delhi - 110 058

 INDIA

Phone:  +91-11-4761 9999     

Fax: +91-11-2553 4163

Email: [email protected]

Head Office

Opp. Baghat Urban Co. Bank,

1st Floor, Rajgarh Road,

Solan - 173212 (H.P.)

Phone: 01792-222 291

Fax: 01792-222-791

Email: [email protected]

Website: www.genaxy.com

Good luck with it.

Best Wishes,

Patricia Linton

Try using insoluble polyvinylpyrrolidone +ascorbic acid to adsorb the humics via hydrogen-bonding, then separate from soluble DNA by centrifugation.

As you can see in my review (Wang Y et al. Extraction of bacterial RNA from soil: challenges and solutions. Microbes Environ. 2012;27(2):111-121), all of the above suggestions will work for your samples. However, the most easy and efficient way is to purify your DNA with a MicroSpin S-400 HR column as I described in a paper (J Appl Microbiol. 2009;107(4):1168-1177). Although in  that case, it was designed for RNA extraction, it also works for DNA samples as I confirmed recently (FEMS Microbiol Ecol. 2014; 88(2):407-423).

Thanks Marjolaine Martin..

Thanks...Frank B. Dazzo sir for your kind suggestion..

Thanks Yong Wang..!!

Try the new PureLink Microbiome DNA Purification Kit – allows one to purify highly clean, inhibitor free DNA in substantial yields. http://www.thermofisher.com/order/catalog/product/A29790?ICID=search-product

You can use activated charcoal filter papers for humic acid removal from DNA. You need to pass your DNA solution through these filters.

Also, If you require DNA metagenomic library preparation, then, use META-G-NOME DNA isolation kit from epicentre.

Chandni Sidhu Hi,

Do you have a protocol or refernce for using activated charcoal filter papers for removing humic acid from DNA samples?