Lisis de Arthrobacter sp. por un nuevo bacteriófago para el control biológico de biomasa derivada de la degradación de ácido tereftálico

Abstract

One of the aspect to consider when bio treating residual waters containing aromatic compounds such as tereftalic acid is the high biomass generated in the treatment. There is a problem when the sludge generated is no longer a product but a residue. Treatment of this sludge, to reduce bacterial number mainly, is costly. Treatment of residual sludge with bacteriophages could represent and effective and inexpensive process to reduce the number of potentially pathogenic bacteria. Bacteriophages are viruses that infect and lyse bacteria specifically and could then be used to lyse bacteria that are present at high number in residual sludge. The main objective of the present thesis was to isolate and characterize bacteriophages from diverse sources of soil and water capable of lysing tereftalic acid-degrading bacteria Arthrobactersp and Brevundimonas sp. Such bacteriophages could then be used to biologically control their growth. A bacteriophage capable of infecting Arthrobactersp was isolated from a soil sample. Using Transmission Electron Microscopy and DNA sequencing the isolated phage was characterized. Some DNA fragments from the phage´s genome, generated by restriction digestion, were cloned into vector pBlueScript II KS and sequenced. TEM images showed phages with isometric capsids and long non-contractile tails, similar to the basal platforms described for the family siphoviridae of the order caudovirales. Two of the DNA fragments sequenced from the phage´s genome showed similarity with the genes coding for a protein in charge of modulating the tail´s length in bacteriophages that infect bacteria of the genus Gordonia and Rhodococcus. The similarity was in the order of 36-41%, which is considered low and may suggest that the isolated phage is related to the bacteriophages that infect bacteria of the mentioned genus but not identical to any reported previously, thus could be a new phage discovered for Arhrobacter. sp.