What is the best way to identify new functions for which we currently know nothing? Here, we discuss the importance of combining cultivation-dependent and -independent approaches to identify new functions and new genes. We argue that although the cultivationdependent approach is presently viewed as an "old fashioned", focusing only on a limited proportion of the total bacterial communities, it remains essential to the characterization as well as the discovery of new potential functions in bacteria. This will allow us to highlight potential model bacterial strains for further genomic and genetic studies and to identify genes of interest. By illustrating an example of a function for which our current knowledge is so far limited, mineral weathering, we highlight different steps necessary to study of the mineral weathering bacterial communities, decipher their respective role as well as their distribution in various ecological niches of the soil.