Ammonia-assimilating microbes in microbial community in a lagoon for wastewater from paddock of dairy cattle

In the present article the distribution and abundance of ammonia-assimilating microbes among the natural habitants in a lagoon were investigated. In the medium containing lagoon-extract, about 20% of total 82 isolates showed ammonia-assimilating ability. By sequencing of 16S ribosomal DNA (rDNA), the highest ammonia-assimilating isolates at 10°C and 37°C were identified as Janthinobacterium lividum and Bacillus sp., respectively. The structure of the microbial community was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Almost of the dominant species that were detected by PCR-DGGE did not coincide with isolates, which showed the high ammonia-assimilating ability, but one specie by PCR-DGGE coincided with ammonia-assimilating isolate. These results suggested that ammonia-assimilating microbes existed as non-dominant species in the microbial community in a lagoon.