Rhamnolipid biosurfactant production by Pseudomonas nitroreducens isolated from petroleum-contaminated soil was investigated. The effects of carbon, nitrogen and carbon to nitrogen ratio on biosurfactant production were examined using mineral salts medium as the growth medium. The tenso-active properties (surface activity and critical micelle concentrations of the produced biosurfactant were also evaluated. The best carbon source, nitrogen source were glucose and sodium nitrate giving rhamnolipid yields of 5.28 and 4.38 g l(-1), respectively. The maximum rhamnolipid production of 5.46 g l(-1) was at C/N (glucose/sodium nitrate) of 22. The rhamnolipid biosurfactant reduced the surface tension of water from 72 to ~37 mN/m. It also has critical micelle concentration of ~28 mg l(-1). Thus, the results presented in our reports show that the produced rhamnolipid can find wide applications in various bioremediation activities such as enhanced oil recovery and petroleum degradation.
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http://dx.doi.org/10.1007/s11274-011-0891-3 | DOI Listing |
Water Res X
May 2025
School of Environmental Science and Engineering, Shandong University, Qingdao, Shandong 266237, China.
Anaerobic ammonia oxidation (anammox) which converts nitrite and ammonium to dinitrogen gas is an energy-efficient nitrogen removal process. One of the bottlenecks for anammox application in wastewater treatment is the stable supply of nitrite for anammox bacteria. Dissimilatory nitrate reduction to ammonium (DNRA) is a process that converts nitrate to nitrite and then to ammonium.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Hunan University, Chemistry and Chemical Engineering, Lushan South Road, Yuelu District, 410082, Changsha, CHINA.
Site density and turnover frequency are the two fundamental kinetic descriptors that determine the oxygen reduction activity of iron-nitrogen-carbon (Fe-N-C) catalysts. However, it remains a grand challenge to simultaneously optimize these two parameters in a single Fe-N-C catalyst. Here we show that treating a typical Fe-N-C catalyst with ammonium iodine (NH4I) vapor via a one-step chemical vapor deposition process not only increases the surface area and porosity of the catalyst (and thus enhanced exposure of active sites) via the etching effect of the in-situ released NH3, but also regulates the electronic structure of the Fe-N4 moieties by the iodine dopants incorporated into the carbon matrix.
View Article and Find Full Text PDFAnal Chem
January 2025
Institute of Molecular Metrology, College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, P. R. China.
The elementary mechanism and site studies of nanozyme-based inhibition reactions are ambiguous and urgently require advanced nanozymes as mediators to elucidate the inhibition effect. To this end, we develop a class of nanozymes featuring single Cu-N catalytic configurations and B-O sites as binding configurations on a porous nitrogen-doped carbon substrate (B/Cu) for inducing modulable inhibition transfer at the atomic level. The full redistribution of electrons across the Cu-N sites, induced by B-O sites incorporation, yields B/Cu with enhanced peroxidase-like activity versus Cu.
View Article and Find Full Text PDFJ Environ Manage
January 2025
College of Resources and environmental Sciences, Gansu Agricultural University, Lanzhou, 730070, China. Electronic address:
Limestone mining in arid regions, particularly within fragile environments, leads to severe environmental pollution and ecological degradation. Developing a scientifically sound and effective ecological rehabilitation strategy is therefore critical. This study constructed a three-dimensional ecological rehabilitation model integrating soil amelioration and vegetation reconstruction.
View Article and Find Full Text PDFAMB Express
January 2025
Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, Cairo, 11566, Egypt.
In this study, Allium sativum, garlic, was selected to isolate endophytic bacteria and to evaluate the antimicrobial, antiviral, antioxidant, and cytotoxic activities of their produced metabolites followed by identification of the biosynthetic gene cluster of the antimicrobial metabolites using Oxford Nanopore Technology (ONT). Two bacterial isolates, C6 and C11, were found to have a broad-spectrum antagonistic effect against four standard microbial strains and were molecularly identified using 16 S ribosomal RNA sequence analysis and deposited in a local culture collection as B. velezensis CCASU-C6, and B.
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