Start-ups say they've found ways to create a vast diversity of biological molecules and enzymes--all potential drugs or drug making tools. The trick is transferring genes from microbes that can;t be grown in the lab (some 95% of known species) into onesthat thrive there. Some new firms are collecting microbes from exotic locales. Potential drug company partners are often excited by the idea, but, because little proof exists that the techniques work to create additional diversity, they remain skeptical.