Metal-Pseudomonas veronii 2E Interactions as Strategies for Innovative Process Developments in Environmental Biotechnology

Abstract

The increase of industrial discharges is the first cause of the contamination of water bodies. The bacterial survival strategies contribute to the equilibrium restoration of ecosystems being useful tools for the development of innovative environmental biotechnologies. The aim of this work was to study the Cu(II) and Cd(II) biosensing, removal and recovery, mediated by whole cells, exopolymeric substances (EPS) and biosurfactants of the indigenous and non-pathogenic Pseudomonas veronii 2E to be applied in the development of wastewater biotreatments. An electrochemical biosensor was developed using P. veronii 2E biosorption mechanism mediated by the cell surface associated to bound exopolymeric substances. A Carbon Paste Electrode modified with P. veronii 2E (CPEM) was built using mineral oil, pre-washed graphite power and 24 h-dried cells. For Cd(II) quantification the CPEM was immersed in Cd(II) (1–25 μM), detected by Square Wave Voltammetry. A similar procedure was used for 1–50 μM Cu(II). Regarding Cd(II), removal mediated by immobilized EPS was tested in a 50 ml bioreactor with 0.13 mM Cd(II), pH 7.5. A 54% metal retention by EPS was achieved after 7 h of continuous operation, while a 40% was removed by a control resin. In addition, surfactants produced by P. veronii 2E were studied for recovery of Cd(II) adsorbed on diatomite, obtaining a 36% desorption efficiency at pH 6.5. Cu(II) adsorption from a 1 mM solution was tested using P. veronii 2E purified soluble EPS in 50 mL- batch reactors (pH = 5.5, 32°C). An 80% of the initial Cu(II) was retained using 1.04 g immobilized EPS. Focusing on metal recovery, Cu nanoparticles (NPs) biosynthesis by P. veronii 2E was carried out in Cu(II)-PYG Broth at 25°C for 5 days. Extracellular CuNPs were characterized by UV-Vis spectral analysis while both extracellular and intracellular NPs were analyzed by SEM and TEM techniques. Responses of P. veronii 2E and its products as biosurfactants, bound and soluble EPS allowed Cu(II) and Cd(II) removal, recovery and biosensing resulting in a multiple and versatile tool for sustainable wastewater biotreatments.

Orally Administrated Lactiplantibacillus plantarum BGAN8-Derived EPS-AN8 Ameliorates Cd Hazards in Rats

“…Furthermore, Prevotella copri was also detected as one of the differential markers for the Cd 50 ppm group, whereas Pseudomonas veronni appeared to be important in the same dose group but that was treated with EPS-AN8, which was also a marker for the 5 ppm Cd group. Interestingly, this was a non-pathogen species that could be a promising tool for sustainable wastewater biotreatments (removal, recovery, and biosensing) of Cd and copper (Cu) [63]. Thus, it is possible that this microenvironment with Cd that was presented in the lower range favors blooming of P. veronni.…”

Beneficial Interactive Effects Provided by an Arbuscular Mycorrhizal Fungi and Yeast on the Growth of Oenothera picensis Established on Cu Mine Tailings

“…The intricate role of microbial EPS production in enhancing soil aggregation, particularly under challenging conditions such as salinity and drought, has been well documented [59][60][61]. Recent studies have further underscored the significant biotechnological potential of EPS, highlighting its efficacy in both the sequestration and remediation of heavy metals [50,62,63].…”

Role of Exopolysaccharides of Pseudomonas in Heavy Metal Removal and Other Remediation Strategies

“…Ferreira et al [ 73 ] noted that the soluble ExP fraction of EPSs produced by Pseudomonas veronii 2E was composed of fucose, galactosamine, glucosamine, galactose, glucose, mannose, and glucuronic acid. It was capable of removing 82.8% of 1 mM copper(II) and the registered sorption capacity was 0.066 mmol·g −1 after 96 h in the kinetic studies [ 74 ]. It was even successfully applied in an effluent biotreatment method for the removal of copper(II) from copper-loaded effluents [ 75 ].…”