Rapid degradation of the Cry3Bb1 protein from Diabrotica-resistant Bt-corn MON88017 during ensilation and fermentation in biogas production facilities

BACKGROUND: Insect-resistant transgenic corn is meeting a growing adoption in Europe. Corn is also the major substrate for biogas production, which has vastly increased in recent years. In areas with high insect pest pressure Bt-corn silage will consequently be fed into biogas production facilities. To assess the potential risks of transgenic plants as energy crops we investigated the fate of the coleopteran-specific protein Cry3Bbl from MON88017 corn in the utilization chain of a farm-scale biogas production facility using ELISA. RESULTS: The mean Cry3Bbl protein content in chaffed MON88017 plant material was lSμg g-1• In silage the content decreased rapidly, with less than 20 ng g-1 detectable after 8 months. From the start of fermentation in the biogas reactor, only trace amounts of Cry3Bbl could be detected. Conventional corn harvested alongside MON88017 with the same equipment showed a presence of transgenic plant material of around 0.5%. Analyses performed at two laboratories showed consistent and systematic differences in the concentrations of Cry3Bbl measured with ELISA due to methodical differences. CONCLUSIONS: An extensive degradation of Cry3Bbl was observed in silage despite differences in ELISA measurements. The potential risk associated with the use of MON88017 silage is discussed on this basis. © 2008 Society of Chemical Industry