Abstract
Municipal and industrial wastewater is often discharged into the environment without appropriate treatment, especially in developing countries. As a result, many rivers and oceans are contaminated. It is urgent to control and administer treatments to these contaminated rivers and oceans. However, most mechanisms of bacterial colonization in contaminated rivers and oceans were unknown, especially in sewage outlets. We found Shewanella putrefaciens to be the primary bacteria in the terrestrial sewage wastewater outlets around Ningbo City, China. Therefore, in this study, we applied a combination of differential proteomics, metabolomics, and real-time fluorescent quantitative PCR techniques to identify bacteria intracellular metabolites. We found S. putrefaciens had 12 different proteins differentially expressed in freshwater culture than when grown in wastewater, referring to the formation of biological membranes (Omp35, OmpW), energy metabolism (SOD, deoxyribose-phosphate pyrophosphokinase), fatty acid metabolism (beta-ketoacyl synthase), secondary metabolism, TCA cycle, lysine degradation (2-oxoglutarate reductase), and propionic acid metabolism (succinyl coenzyme A synthetase). The sequences of these 12 differentially expressed proteins were aligned with sequences downloaded from NCBI. There are also 27 differentially concentrated metabolites detected by NMR, including alcohols (ethanol, isopropanol), amines (dimethylamine, ethanolamine), amino acids (alanine, leucine), amine compounds (bilinerurine), nucleic acid compounds (nucleosides, inosines), and organic acids (formate, acetate). Formate and ethanolamine show significant difference between the two environments and are possibly involved in energy metabolism, glycerophospholipid and ether lipids metabolism to provide energy supply, and material basis for engraftment in sewage. Because understanding S. putrefaciens’s biological mechanism of colonization (protein, gene express, and metabolites) in terrestrial sewage outlets is so important to administering and improving contaminated river and to predicting and steering performance, we delved into the biological mechanism that sheds light on the effect of environmental conditions on metabolic pathways.
Highlights
With the increase of human activities and industrial processes, more urban and industrial wastewaters are discharged to rivers or oceans without appropriate treatment, especially in developing countries (Yan et al, 2015)
We found that S. putrefaciens was present in high abundance at almost every sewage outlet most of the time (Figure S2 in Supplementary Material)
The total protein concentrations of S. putrefaciens grown in sewage (D) and freshwater (W) were determined as 8.46 and 9.74 μg/μL, respectively
Summary
With the increase of human activities and industrial processes, more urban and industrial wastewaters are discharged to rivers or oceans without appropriate treatment, especially in developing countries (Yan et al, 2015). The bacterium is a Gram-negative non-fermentative oxidative bacillus, which was previously known as Pseudomonas putrefaciens, first isolated by Debby and Hammer (1931) It is commonly found in water-related environments such as freshwater, seawater, lakes, rivers, sewage, fish, and soil (Bulut et al, 2004; Basir et al, 2012). Under static and low oxygen conditions, S. putrefaciens isolated from printing and dyeing sewage, such as the S. putrefaciens strain AS96, has a strong ability to treat dye-containing industrial effluents containing high concentrations of salt (Khalid et al, 2008). It can affect some fish species as an opportunistic pathogen
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
