Isolation of Novel Aerobic denitrifier and optimization of process parameters for biological denitrification using RSM

Abstract

The study aimed to isolate and characterize a high efficiency novel bacterium for denitrification in waste water and also to optimize process parameters under aerobic condition. One of the bacteria chosen among four, displayed a maximum of 98% reduction of nitrate. The strain was identified as Enterobacter sp. NCCP-29 by biochemical tests and further identified based on similarity of PCR-16S rRNA using universal primers. The parameters (pH, temperature, agitation speed, C:N ratio) which effect the denitrification were screened using one factor at a time. The pH, temperature and C:N ratio exhibited significant effect on the denitrification using Enterobacter sp. NCCP-29. The levels of these parameters were optimized using a central composite design (CCD). A maximum of 98% denitrification was achieved at pH 6.5, temperature 30°C and C: N ratio of 3:1. The second order model was generated and found to have a good fit with R2 value of 0.93. Investigations revealed the ability of Enterobacter sp. NCCP-29 to remove nitrate under aerobic conditions. © 2019, Slovak University of Agriculture.