Investigation of nitrite oxidoreductase (NOR) expression in an enriched NOB microbiome at different temperatures

BACKGROUND AND OBJECTIVESNitrite oxidizing bacteria (NOB) will oxidize nitrite to nitrate (NO۳-), using the enzyme called nitrite oxidoreductase (NXR). The aim of this study was investigation total NOR expression in a microbiome containing enriched NOB bacteria.MATERIALS AND METHODSEnriched microbial communities containing ۶.۱% Nitrobacter winogradskyi were prepared and transferred to NOB liquid media. Nitrite reduction and NXR gene expression were then measured at different temperatures. Specific q-PCR primers for NXR genes were designed for NOB strains, respectively. In addition, a constitutively expressed gene (۱۶S rRNA gene) was used as an internal reference for selected strains. RNA was extracted from samples of microbial communities adapted to different temperatures and stored at -۸۰ °C. cDNA was synthesized from the isolated RNA. Expression of NOR genes was analyzed by q-PCR.RESULTS AND DISCUSSIONTo the expression of key NXR genes involved in these respective processes. The highest expression of NXR occurred in a temperature range of ۲۵-۳۰ °C. Nitrite is reduced to nitrate by the enzyme NXR, whose differential expression was detected in the microbiome. NXR expression correlated very well with community nitrite degradation activityCONCLUSIONIn this study, we report an enriched NOB bacterial microbial community that removes nitrite at different temperatures so that it is proposed for water with high nitrite concentration for bioremediation systems, especially for aquaculture wastewater.

کلیدواژه ها:

Nitrite oxidizing bacteria (NOB) ، nitrite oxidoreductase (NXR) ، microbial community ، aquaculture