Karakterisasi Molekular dan Uji Aktivitas Bakteri Pereduksi Nitrat dari Muara Cimandiri Pelabuhan Ratu Sukabumi Jawa Barat

Abstract

The activity of nitrate reducing bacteria in aquatic environment can produce nitrous oxide (N2O) via either denitrification and dissimilative nitrate reduction to ammonium processes. This research isolated and characterized nitrate reducing bacteria from Cimandiri Estuary. Twenty-two isolates of nitrate reducing bacteria isolated from enrichment medium with 100 μM and 2000 μM nitrate, 15 isolates were denitrifier bacteria and 7 isolates were dissimilative nitrate ammonifier bacteria. NFR1, NFR2, NFR3, NFR4, FR1 and FR2 isolates had the higher nitrate reducing activity. The activity of nitrate reduction was started in the first hour incubation and the highest nitrate reducing activity was occured during the exponential phase after 12 hours incubation. The Vmax value of NFR1, NFR2, NFR3, NFR4, FR1 and FR2 isolates were 0.65 mM.h-1, 0.49 mM.h-1, 0.25 mM.h-1, 0.27 mM.h-1, 0.38 mM.h-1 and 0.56 mM.h-1, respectively. While Km value were 2.93 mM, 3.16 mM, 1.40 mM, 1.15 mM, 1.78 mM and 2.93 mM, repectively. While umax value were 0.34 cell.h-1, 0.22 cell.h-1, 0.14 cell.h-1, 0.19 cell.h-1, 0.21 cell.h-1 and 0.33 cell.h-1, respectively. Based on 16S-rRNA sequence similarity, NFR1 isolate was closely related to Microbacterium sp; NFR2 and NFR4 isolates were closely related to Shewanella algae; FR2 isolate was closely related to Shigella flexneri.