Biodegradation of 4-nitrophenol by a Rhodococcus species and a preliminary insight into its toxicoproteome based on mass spectrometry analysis

Abstract

The objective of this study was to understand the possible fate of 4-NP through the molecular mechanism and to identify potential enzymes involved in 4-NP biodegradation by Rhodococcus sp. strain BUPNP1. Biodegradation of 4-NP was detected spectrophotometrically at 400 nm and also confirmed by TLC and HPLC. Comparative study of proteomes was performed by 2-D gel electrophoresis followed by peptide mass fingerprinting and bioinformatic analysis to identify and/ or predict the possible functions of over-expressed proteins in 4-NP treated cells of BUNP1. Utilization of 4nitrophenol and its hydrolysis intermediate 4-nitrocatechol (4-NC) and 1,2,4-Benzenetriol as sole carbon source indicated the presence of genomic information encoding the enzyme necessary for the operation of 4-nitrophenol degradation pathway in the strain BUPNP1. It could transform 4-NP into 4-NC by monooxygenase whose major activity was detected during initial stage of degradation. The 4-NC further depleted in the medium to release nitrite ions. In order to investigate the molecular changes occurring d u r i n g d e g r a d a t i o n , a comparative study of proteome profiles was carried out where; 4nitrophenol treated cells were compared against cells grown on glucose as control. The comparative study indicated expression of several protein spots under 4-nitrophenol treated condition. This study showed the potential of BUPNP1 strain belonging to genus Rhodococcus towards induced expression of some unique proteins which might have possible role in 4-NP biodegradation process.

Decolorization of p-nitrophenol and draft genome sequence of Pseudomonas sp. strain PNPG3: A preliminary report

“…Over the past few decades, due to its wide application, persistent, toxic, recalcitrant nature, PNP is considered as one of the well-known priority pollutants by the United States Environmental protection agency (Alam and Saha, 2022b). It is reported to have wide environmental distribution (Nielsen et al, 2011;Sengupta et al, 2018). PNP is an uncoupler of oxidative phosphorylation and is reported to act as a mutagenic and carcinogenic agent (Kitagawa et al, 2004;Arora, 2012).…”

“…PNP is an uncoupler of oxidative phosphorylation and is reported to act as a mutagenic and carcinogenic agent (Kitagawa et al, 2004;Arora, 2012). Moreover, this water-soluble, toxic compound is also produced as a hydrolysis product from extensively used organophosphate agrochemicals like parathion, methyl parathion, and herbicides like dinoseb and dinitrocresol (Prakash et al, 1996;Labana et al, 2005;Sengupta et al, 2018). The maximum permissible limit of PNP is documented to be 10ng -1 ml in the natural water bodies (Kulkarni and Chaudhari, 2006).…”

“…strain DS001; Citriococcus nitrophenolicus strain PNP1; Rhodococcus sp. BUPNP1 (Prakash et al, 1996;Pakala et al, 2007;Nielsen et al, 2011;Sengupta et al, 2018). However, these bacterias have been reported from soil ecosystems.…”