Genetically engineered bacterium kills plants instead of helping them!
As far as the intended goals were concerned -- eliminating rotting organic waste and producing ethanol -- the genetically engineered bacterium was a success. But when a doctoral student named Michael Holmes decided to add the post-processed waste to actual living soil, something happened that no one expected. The seeds that were planted in soil mixed with the engineered Klebsiella sprouted, but then every single one of them died.
What killed them? The genetically engineered Klebsiella turned out to be highly competitive with native soil micro-organisms. Plants are only able to take nitrogen and other nourishment from the soil with the help of fungi called mycorrhizae. These fungi live in the soil and help make nutrients available to plant roots. But when the genetically engineered Klebsiella was introduced into living soils, it greatly reduced the population of mycorrhizal fungi in the soil. And without healthy mycorrhizal fungi in soils, no plants can survive.