Dear Haider,

You first have to understand that one of the greatest disadvantages of culture-based methods for the study of microorganisms is that these methods are biased. That is, they usually allow for the growth of some organisms over others. As such, there is a very significant number of organisms that have not been previously cultured. The world harbours more microorganisms than what we currently know. When using metagenomics to study microbial populations in any given system, these are the organisms that usually appear as "uncultured".

I recommend you read this paper:

"Metagenomics: Application of Genomics to Uncultured Microorganisms" by Jo Handelsman.

MICROBIOLOGY AND MOLECULAR BIOLOGY REVIEWS, Dec. 2004, p. 669–685 Vol. 68, No. 4. DOI: 10.1128/MBR.68.4.669–685.2004

I hope this helps give direction to your search for an appropriate answer.

Regards

King

Dear Haider,

You first have to understand that one of the greatest disadvantages of culture-based methods for the study of microorganisms is that these methods are biased. That is, they usually allow for the growth of some organisms over others. As such, there is a very significant number of organisms that have not been previously cultured. The world harbours more microorganisms than what we currently know. When using metagenomics to study microbial populations in any given system, these are the organisms that usually appear as "uncultured".

I recommend you read this paper:

"Metagenomics: Application of Genomics to Uncultured Microorganisms" by Jo Handelsman.

MICROBIOLOGY AND MOLECULAR BIOLOGY REVIEWS, Dec. 2004, p. 669–685 Vol. 68, No. 4. DOI: 10.1128/MBR.68.4.669–685.2004

I hope this helps give direction to your search for an appropriate answer.

Regards

King

There are many perhaps a major fractions of microbial species living in the surrounding environments are known to exist but are not culturable in the laboratory, the so-called “viable but nonculturable” (VBNC) due to the special culture conditions they require to grow. Majority of microbes can not be grown on conventional culture media due to the lack of knowledge for their growth requirements. In addition, many species of microbes enter into starvation mode of metabolism or VBNC state under stress conditions.

You can have a better knowledge by reading the following papers:

Zhao, X., Zhong, J., Wei, C., Lin, C. W., & Ding, T. (2017). Current perspectives on viable but non-culturable state in foodborne pathogens. Frontiers in microbiology, 8, 580.

Lee, S., & Bae, S. (2017). Molecular viability testing of viable but non‐culturable bacteria induced by antibiotic exposure. Microbial biotechnology.

Zhong, J., & Zhao, X. (2018). Detection of viable but non-culturable Escherichia coli O157: H7 by PCR in combination with propidium monoazide. 3 Biotech, 8(1), 28.

Only a very low percentage of bacteria can be cultured under laboratory conditions. Due to very high diversity and low information available about such bacteria, they can not be studied by conventional laboratory methods. But the fact is that, they are of majority and plays crucial role in environmental systems. Some, recent techniques like metagenomic approaches are useful for studying such bacteria.

You will get some information about the viable but nonculturable organisms from this article " The importance of the viable but non-culturable state in human bacterial pathogens".