Figure 1.

In BGF for microbial natural product discovery, the culture extract is fractionated using chromatographic methods. Fractionation is an iterative process guided by screening for the desired bioactivity until the isolation of a pure compound. This workflow was invented by Selman Waksman and has facilitated the identification of the vast majority of natural products known to date. However, it has fallen out of favor due to unacceptably high rediscovery rates, because BGF has nearly exhausted the rather limited chemical space it can access.