Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 5, 1996
Publication Date: N/A
Interpretive Summary: Nitrophenols are pollutants which are commonly found in industrial wastewater. They are toxic to plants, fish and many other organisms. Nitrophenols are listed by the United States Environmental Protection Agency as priority pollutants. Unfortunately, they are accumulating in the environment at a worrisome rate. In this study, three bacteria were examined for their ability to degrade a representative member of the nitrophenol family. All degraded the nitrophenol to benign materials. But, very unexpectedly and more importantly, it was also discovered that two of the bacteria degraded the nitrophenol in preference to a much better food source, glucose. This means that these particular organisms are attractive candidates for biological removal of nitrophenols because they will degrade nitrophenols even when more easily degraded compounds are available in the environment. The research provides fundamental information needed to utilize biological agents, such as bacteria, to remove environmental pollutants. The research particularly benefits industrial producers of organic chemicals, as well as the general populous which is ever more concerned about a cleaner environment.
Two indigenous and one alien bacterial strains were evaluated for their ability to degrade p-nitrophenol (PNP) in pure culture. Additionally, these strains were inoculated into industrial wastewater to enhance the degradation of PNP in the presence or absence of glucose, an easily utilized alternative substrate. All three strains enhanced the degradation of high concentrations of PNP (20 ug/ml) with or without added glucose. At high concentrations of PNP and glucose (100 ug/ml), alien strain Corynebacterium Z-4 utilized glucose and PNP simultaneously. Unexpectedly, indigenous strains Pseudomonas putida and Corynebacterium Z-2 utilized PNP first. The behavior of the alien isolate Corynebacterium Z-4 was also somewhat surprising because when inoculated into lake water containing low concentrations of PNP (26 ng/ml) and high concentrations of glucose, it preferentially utilized glucose (Zaidi et al. 1995). However, in industrial wastewater containing the same PNP and glucose concentrations, it instead switched and utilized PNP first.