Denitrifying Bacteria can be Enumerated in Nitrite Broth1
- M. G. Volz2
Denitrifying- and NO3- reducing bacteria in air dry, moist, and organic matter amended Yalesville fsl (Typic Dystrochrept), lake water, and in both effluent and drainage field soil from a septic tank system were enumerated using Difco nutrient broth, which contained either or both NO3- and NO2- and was incubated anaerobically. Most probable numbers (MPN) of denitrifiers (1.3 × 103 to 1.1 × 107/g) were always less than those of NO3- reducers (1.5 × 106 to 8.1 × 107/g) in the same sample, and constituted from 0.02% to 70% of bacteria capable of aerobic growth on yeast extract agar. Further, for a given sample, denitrifier populations as estimated in nutrient broth + NO2- (NO2- broth) were always statistically equivalent to or larger than those determined using nutrient broth + NO3- (NO3- broth). Therefore, NO2- broth may be preferable to NO3- broth for estimating denitrifier populations in soil and water samples. Nitrite broth retains the nutritional advantages of nutrient broth but also represses competitive growth effects of NO3- reducing bacteria. Further, in order to determine when in vitro denitrification has occurred, one needs only to assess colorimetrically the presence of NO2- following culture tube incubation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © .