Cadmium and cadmium-tolerant soil bacteria in cacao crops from northeastern Colombia

Aims This research aims to assess total-cadmium soil content and microbiological aspects to understand the dynamics of culturable cadmium-tolerant bacteria (CdtB) in cacao soils from northeastern Colombia.Methods and Results An integration of inverted dish plating, Cd determination and a microcalorimetry assay (IMC) was carried out. A farm in Boyaca showed the highest level of total soil Cd (374mgkg(-1)) followed by farms in Santander and Arauca (276 and 116mgkg(-1), respectively). Coefficient of determination between total soil Cd and CFU of CdtB was high (R-2=083) for the farm in Boyaca. Moreover, a pool of 129 CdtB was isolated, and phylogeny of 21 CdtB was discussed. Among CdtB strains isolated, Enterobacter sp. CdDB41 showed major Cd immobilization capacity (Q(max) of 221 and 232J at 6 and 24mgl(-1) of CdCl2), with an immobilization rate of 0220mgkg(-1)h(-1).Conclusions Among CdtB strains isolated, Enterobacter sp. CdDB41 showed major Cd immobilization capacity (Q(max) of 221 and 232J at 6 and 24mgl(-1) of CdCl2), with an immobilization rate of 0220mgkg(-1)h(-1).Significance and Impact of the Study Nothing is known about soil CdtB in cacao. Our data showed that CdtB such as Enterobacter sp. has high immobilization capacity. Furthermore, the otavite found insitu might be mineralized due to the bacterial metabolic activity of CdtB.