Microbial community development of biofilm in Amaranth decolourization technology analysed by FISH

Abstract

The aim of this study was to elucidate the role, the space distribution and the relationships of the bacteria from the genus Pseudomonas in a biofilm community during semi-continuous Amaranth decolourization process in model sand biofilters. The examined parameters of the process were as follows: technological parameters; key enzyme activities (azoreductase, succinate dehydrogenase, catechol-1,2-dioxygenase, catechol-2,3-dioxygenase); the number of azo-degrading bacteria and the bacteria from genus Pseudomonas (plate count technique); the amount and the location of Pseudomonas sp. using fluorescent in situ hybridization (FISH).The results showed that the increase of the Amaranth removal rate with 120% was accompanied with increase of the enzyme activities of the biofilm (azoreductase activity – with 25.90% and succinate dehydrogenase – with 10.61%). The enzyme assays showed absence of activity for сatechol-1,2-dioxygenase and catechol-2,3-dioxygenase at the early phase and high activities of the same oxygenases at the late phase (2.76 and 1.74 μmol/min mg protein, respectively). In the beginning of the process (0–191 h), the number of the culturable microorganisms from genus Pseudomonas was increased with 48.76% but at the late phase (191–455 h) they were decreased with 15.25% while the quantity of the non-culturable bacteria from this genus with synergetic relationships was increased with 23.26%.The dominant microbial factors were identified in the structure of the biofilm during the azo-degradation process by using FISH analysis. Furthermore, the inner mechanisms for increase of the rate and the range of the detoxification were revealed during the complex wastewater treatment processes.

Purposely Development of the Adaptive Potential of Activated Sludge from Municipal Wastewater Treatment Plant Focused on the Treatment of Landfill Leachate

“…Reaching the critical concentration of the pollutants in the landfill leachate was related to the raised concentration of pollutants fed into the reactor and to the adsorption and absorption of toxic pollutants in the flocs and their subsequent accumulation. We registered similar effects in other processes with activated sludge at the entry of dyes, fuel oil, nitrophenols, chlorophenols, and others into treatment plants [32,54,56,57]. These accumulated contaminants in the flocs of the sludge can also be seen in the photos (Figure 7).…”

“…External calibration by multi-element standard solution was performed. The concentrations of the elements were determined using the isotopes as follows: macroelements ( 27 Al, 136, 138 Ba, 42,44 Ca, 54,57 Fe, 39 K, 24,25,26 Mg, 55 Mn, 23 Na, 31 P and 28 Si) and the micro-and trace elements ( 107,109 Ag, 75 As, 209 Bi, 110,112,114 Cd, 59 Co, 52 Cr, 133 Cs, 63,65 Cu, 200 Hg, 139 La, 96,98 Mo, 60,62 Ni, 204,208 Pb, 85,87 Rb, 121,123 Sb, 77,78 Se, 118,120 Sn, 86,88 Sr, 46,48 Ti, 232 Th, 238 U, 51 V and 64,66 Zn). The simultaneous determination of all elements in the samples was achieved by reducing the signal of the macroelements thanks to the application of a dynamic bandpass tuning parameter RPa, as described in Lyubomirova [37].…”

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“…The most important of them, as being able to participate in both the xenobiotics biodegradation and the denitrification, are the bacteria in the genus Pseudomonas. In our previous studies their key role in the detoxification of different pollutants had been demonstrated [49][50][51]. Details related to the importance of their spatial arrangement and the unculturable part of the group had been elucidated [49,51].…”

Textile azo dye decolorization and detoxification using bacteria isolated from textile effluents

“…They have better resistance to fluctuations in loads, starvation periods, and washouts (Chandran and Das, 2011). In the previous investigation (Belouhova et al, 2014), the bacteria from genus Pseudomonas played an important role in the adaptation of biofilms for the biodegradation of azo dyes. This study focused on increasing the potential of tested isolates to generate stable bonding with the abiotic surface in the form of a biofilm (Rajendran et al, 2015).…”

“…The phylogenetic dendograms of the isolates are shown in Figure 1. The ability to produce biofilm of tested isolates using adherence assay A biofilm is an assemblage of microbial cells that are irreversibly associated (not removed by gentle rinsing) with a surface and enclosed in a matrix of primarily polysaccharide material (Belouhova et al, 2014). Microorganisms attach to surfaces and develop biofilms, and biofilm-associated cells can be distinguished from their suspended counterparts because of their generation of an extracellular polymeric substance (EPS) matrix, reduced growth rates, and the up-and down-regulation of specific genes (Cerron et al, 2015).…”