Monitoring of the evolving diversity of the microbial community present in rotifer cultures

The genetic fingerprint of the microbiota in the culture water of two different rotifer culture systemsZbatch versus recirculation.was obtained by means of denaturing gradient gel electrophoresisZDGGE. of 16S rRNA gene fragments. The genetic profile of the bacterial community present in the culture water of a batch culture system changed daily due to shifts occurring at the level of the dominance of bands. By means of statistical tools, it was possible to distinguish three different periods during the development of the microbiota in the recirculation experiment, each corresponding to a typical period during the production of rotifers. Overall, it was obvious that the microbiota in such a recirculation system was less susceptible for variation relative to the microbiota in a batch system. However, some shifts in the genetic profile were observed when technical problems occurred resulting in a reduced water quality or performance of the biofilter. Characterisation of the microbial community present in the recirculation system indicated that the sequences of typical bands showed the highest level of identity to the sequences from the bacterial strain MMB-1T Zrepresenting a species in the genus Marinomonas, Marinomonas mediterranea sp.., M. Õaga and Pseudoalteromonas haloplanktis spp. tetraodonis strain IAM 14160-98 porcent.