Why can't all microorganisms from the natural environment be isolated in a lab?

Question:

Environmental vs. Lab Grown Bacteria:

It has been estimated that within one gram of a soil sample could reside over 40 million bacterial cells. Likewise, many bacteria reside within biofilms - slimy masses of bacteria and bacterial secretions. These types of environments contain many species of not only bacteria but also fungi, protists, and small invertebrates. These micro ecosystems consist of complex interactions between organisms where each species may contribute as a primary or secondary consumer or producer. Within the food web, bacteria and the other species contribute to the immediate environment and may provide specialized nutrients for other species.

Lab grown bacteria are usually cultured in liquid or solid media which provides a source of nutrients and carbon for the microbes. Many bacteria can be successfully grown in this manner, however it is estimated that as few as 1% of all bacteria species can actually be cultured in this manner. In addition, lab grown cultures are intended to be pure - that is that they only consist of a single species.

Answer and Explanation: 1