Structural and fractal characteristics of biofilm attached on the surfaces of aquatic plants and gravels in the rivers and lakes reusing reclaimed wastewater

Liang, Mingchao; Wang, Tianzhi; Li, Yunkai; Yang, Peiling; Liu, Chengcheng; Li, Pengxiang; Zhao, Wei

doi:10.1007/s12665-013-2285-3

Cited by 19 publications

(1 citation statement)

References 22 publications

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“…Taking into consideration the importance of controlling bacterial biofilms, they have become the objects of interdisciplinary research. The most important areas are presented by the modeling of biomass growth (density and rate of progress) [14][15][16][17][18][19][20], the mechanisms of regulation of key chemical compounds related to the quorum sensing [21][22][23][24][25][26][27][28], and the study of the geometric characteristics of the complex morphology of the observed structures [29][30][31].…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Cellular Automaton for Modeling of Self-Similar Evolution in Biofilm-Forming Bacterial Populations

Sarukhanian,

Maslovskaya,

Kuttler

2023

Mathematics

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Bacterial populations often form colonies and structures in biofilm. The paper aims to design suitable algorithms to simulate self-similar evolution in this context, specifically by employing a hybrid model that includes a cellular automaton for the bacterial cells and their dynamics. This is combined with the diffusion of the nutrient (as a random walk), and the consumption of nutrients by biomass. Lastly, bacterial cells divide when reaching high levels. The algorithm computes the space-time distribution of biomass under limited nutrient conditions, taking into account the collective redistribution of nutrients. To achieve better geometry in this modified model approach, truncated octahedron cells are applied to design the lattice of the cellular automaton. This allows us to implement self-similar realistic bacterial biofilm growth due to an increased number of inner relations for each cell. The simulation system was developed using C# on the Unity platform for fast calculation. The software implementation was executed in combination with the procedure of surface roughness measurements based on computations of fractional dimensions. The results of the simulations qualitatively correspond to experimental observations of the population dynamics of biofilm-forming bacteria. Based on in silico experiments, quantitative dependencies of the geometrical complexity of the biofilm structure on the level of consumed nutrients and oxygen were revealed. Our findings suggest that the more complex structure with a fractal dimension of the biofilm boundaries (around 2.6) corresponds to a certain range of nutrient levels, after which the structure degenerates and the biofilm homogenizes, filling the available space provided and tending towards a strictly 3D structure. The developed hybrid approach allows realistic scenario modeling of the spatial evolution of biofilm-forming bacterial populations and specifies geometric characteristics of visualized self-similar biofilm bacterial structures.

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Section: Introductionmentioning

confidence: 99%

Three-Dimensional Cellular Automaton for Modeling of Self-Similar Evolution in Biofilm-Forming Bacterial Populations

Sarukhanian,

Maslovskaya,

Kuttler

2023

Mathematics

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Role of extracellular polymeric substances (EPS) production in bioaggregation: application to wastewater treatment

Ding

Bourven

Guibaud

et al. 2015

Appl Microbiol Biotechnol

198

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This paper reviews the formation, structure, and stability of bioaggregates with an emphasis on the composition and distribution of extracellular polymeric substances (EPS) and their role in bioaggregation. Bioaggregation is ubiquitous in natural environment and is of great importance in biological wastewater treatment processes. It greatly influences the flocculability, settleability, and dewaterability for flocs and sludge retention and shear resistance for biofilms. The physico-chemical and microbial structures of bioaggregates are dependent on operational conditions as well as microbial diversity and spatial distribution. The formation of bioaggregates is mediated by the physico-chemical interactions as well as the microbial interactions such as EPS production and quorum sensing. EPS are composed of a mixture of macromolecules including proteins, polysaccharides, humic-like substances, and nucleic acids, which entrap the microbial cells in a three-dimensional matrix. The composition and physico-chemical characteristics of EPS have significant influence on the maintenance of the bioaggregate structure and the process performance of the wastewater treatment. However, the mechanisms of bioaggregation are still unclear and the conclusions on the role of EPS were mostly drawn from the established correlations and hypotheses. This paper expects to provide up-to-date knowledge on bioaggregation and insights for further studies and applications.

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Biofilms on the surface of gravels and aquatic plants in rivers and lakes with reusing reclaimed water

Wang

Liang

et al. 2013

Environ Earth Sci

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Reuse of reclaimed water for the eco-environmental water has become an effective measure to resolve the urban water crisis. However, it still contains large amounts of contaminants which may significantly affect the aquatic ecosystems. Biofilm attached on the surface of multiple matrixes in rivers and lakes is one of the indicators for describing the health of aquatic ecosystem. In this article, we chose eight rivers and lakes as the sampling locations, including three kinds of reclaimed water with different treatment processes and natural water. The morphology, structure and component characteristics of biofilms attached on the surface of aquatic plants and gravels in eight water bodies were evaluated. The results showed that the biofilm on the matrix surface were typical porous media with basic skeleton composed of inorganic particles, microorganisms and algae. The pores were filled with the viscous extracellular polymeric substances (EPS) secreted by microorganisms. The biofilms contained calcite, quartz, illite, alkali feldspar, dolomite, clinochlore, goethite and inorganic salt, and approximately 50 % of these compositions are calcite and quartz. The concentration of EPS was 20.78-500.44 μg/mL, and that of the gravel biofilms was less than that in aquatic plants by 18.1-75.3 %. In these three reclaimed waters, 4-7 kinds of PLFA (phospholipid fatty acid) were detected in aquatic plants biofilms, more than one or two kinds than in gravel biofilms. And the dominant PLFA were i15:0 and 18:0, the total contents of which were, respectively, 74.4, 62.9 and 85.9 % in the three kinds of reclaimed water. All biofilm samples contain major microorganisms such as Pseudomonas, Acinetobacter and Comamonas. This study is aimed to provide some support for assessing the health of riverlake ecosystem with biofilm indicator.

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Structural and fractal characteristics of biofilm attached on the surfaces of aquatic plants and gravels in the rivers and lakes reusing reclaimed wastewater

Cited by 19 publications

References 22 publications

Three-Dimensional Cellular Automaton for Modeling of Self-Similar Evolution in Biofilm-Forming Bacterial Populations

Three-Dimensional Cellular Automaton for Modeling of Self-Similar Evolution in Biofilm-Forming Bacterial Populations

Role of extracellular polymeric substances (EPS) production in bioaggregation: application to wastewater treatment

Biofilms on the surface of gravels and aquatic plants in rivers and lakes with reusing reclaimed water

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