This work shows the behavior of new carbon xerogel films as bacteria supports to remove nitrates from water solution. The preparation method of carbon-xerogel films with well developed mesoporosity obtained by microwave assisted carbonization, as well as the particular effects that the microwaves produce during the carbonization process on the final chemical characteristic of these materials, have been described. Bacteria Escherichia coli were supported on the films working well in the denitrification process of water solutions. Low carbonization degree and/or more acid pH of point of zero charge favor the Gram negative bacteria growth on these types of films. (C) 2014 Elsevier B.V. All rights reserved.