scholarly journals Ferroferric Oxide Significantly Affected Production of Soluble Microbial Products and Extracellular Polymeric Substances in Anaerobic Methanogenesis Reactors

2018 ◽  
Vol 9 ◽  
Author(s):  
Qidong Yin ◽  
Kai He ◽  
Shinya Echigo ◽  
Guangxue Wu ◽  
Xinmin Zhan ◽  
...  
Keyword(s):  
Extracellular Polymeric Substances ◽  
Soluble Microbial Products ◽  
Ferroferric Oxide ◽  
Microbial Products

scholarly journals Biomass Characteristics and Their Effect on Membrane Bioreactor Fouling

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2867 ◽  
Author(s):  
Petros K. Gkotsis ◽  
Anastasios I. Zouboulis
Keyword(s):  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Extracellular Polymeric Substances ◽  
Membrane Surface ◽  
Membrane Resistance ◽  
Soluble Microbial Products ◽  
Gelling Properties ◽  
Microbial Products ◽  
Soluble Part

Biomass characteristics are regarded as particularly influential for fouling in Membrane Bio-Reactors (MBRs). They primarily include the Mixed Liquor Suspended Solids (MLSS), the colloids and the Extracellular Polymeric Substances (EPS). Among them, the soluble part of EPS, which is also known as Soluble Microbial Products (SMP), is the most significant foulant, i.e., it is principally responsible for membrane fouling and affects all fundamental fouling indices, such as the Trans-Membrane Pressure (TMP) and the membrane resistance and permeability. Recent research in the field of MBRs, tends to consider the carbohydrate fraction of SMP (SMPc) the most important characteristic for fouling, mainly due to the hydrophilic and gelling properties, which are exhibited by polysaccharides and allow them to be easily attached on the membrane surface. Other wastewater and biomass characteristics, which affect indirectly membrane fouling, include temperature, viscosity, dissolved oxygen (DO), foaming, hydrophobicity and surface charge. The main methods employed for the characterization and assessment of biomass quality, in terms of filterability and fouling potential, can be divided into direct (such as FDT, SFI, TTF100, MFI, DFCM) or indirect (such as CST, TOC, PSA, RH) methods, and they are shortly presented in this review.

Effect of continuously dosing Cu(II) on pollutant removal and soluble microbial products in a sequencing batch reactor

2015 ◽  
Vol 72 (9) ◽  
pp. 1653-1661 ◽  
Author(s):  
YangWei Yan ◽  
YuWen Wang ◽  
Yan Liu ◽  
Xiang Liu ◽  
ChenChao Yao ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Extracellular Polymeric Substances ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Pollutant Removal ◽  
Cod Removal ◽  
Synthetic Wastewater ◽  
Soluble Microbial Products ◽  
Cod Removal Efficiency ◽  
Microbial Products

The effects of synthetic wastewater that contained 20 mg/L Cu(II) on the removal of organic pollutants in a sequencing batch reactor were investigated. Results of continuous 20 mg/L Cu(II) exposure for 120 days demonstrated that the chemical oxygen demand (COD) removal efficiency decreased to 42% initially, followed by a subsequent gradual recovery, which peaked at 78% by day 97. Effluent volatile fatty acid (VFA) concentration contributed 67 to 89% of the influent COD in the experimental reactor, which indicated that the degradation of the organic substances ceased at the VFA production step. Meanwhile, the varieties of soluble microbial products (SMP) content and main components (protein, polysaccharide, and DNA) were discussed to reveal the response of activated sludge to the toxicity of 20 mg/L Cu(II). The determination of Cu(II) concentrations in extracellular polymeric substances (EPS) and SMP throughout the experiment indicated an inverse relationship between extracellular Cu(II) concentration and COD removal efficiency.

The role of extracellular polymeric substances in biofilm community assembly and metabolic functions

2020 ◽  
Author(s):  
Yichao Wu
Keyword(s):  
Microbial Community ◽  
Extracellular Polymeric Substances ◽  
Extracellular Dna ◽  
Transcriptional Analysis ◽  
Synthetic Wastewater ◽  
Soluble Microbial Products ◽  
Exogenous Bacteria ◽  
Real Wastewater ◽  
Microbial Products ◽  
Biofilm Development

<p>Compared with the chemically defined synthetic wastewater (SynWW), real wastewater has been reported to exhibit distinct effects on microbial community development. Whether and how soluble microbial products in real wastewater contribute to different effects of synthetic and real wastewater on the fate of exogenous bacteria remains elusive. In this study, using a model wastewater bacterium <em>Comamonas testosteroni</em>, we first examined the influences of microfiltration filter-sterilized real wastewater (MF-WW) and SynWW on the retention of <em>C. testosteroni</em> in established wastewater flocs during bioaugmentation. In bioreactors fed with MF-WW, augmentation of <em>C. testosteroni</em> to wastewater flocs resulted in a substantially higher abundance of the augmented bacterial cells than those fed with SynWW. To identify the soluble microbial products in MF-WW contributing to the observed differences between bioaugmentation reactors fed with MF-WW and SynWW, we examined the effect of MF-WW and SynWW on the growth, floc formation, and biofilm development of <em>C. testosteroni</em>. When <em>C. testosteroni</em> grew in MF-WW, visible flocs formed within 2 h, which is in contrast to cell growth in SynWW where floc formation was not observed. We further demonstrated that the observed differences were mainly attributed to the high molecular weight fraction of the soluble extracellular polymeric substances (EPS) in MF-WW, in particular, proteins and extracellular DNA. The DLVO analysis suggested that, in the presence of soluble EPS, the bacterial cell surface exhibits an increased hydrophobicity and a diminished energy barrier, leading to irreversible attachment of planktonic cells and floc formation. The RNA-seq based transcriptional analysis revealed that, in the presence of soluble EPS, genes involved in nonessential metabolisms were downregulated while genes coding for Cco (cbb3- type) and Cox (aa3-type) oxidases with different oxygen affinities were upregulated, facilitating bacterial survival in flocs. Taken together, this study reveals the mechanisms underlying the contribution of soluble EPS to the recruitment of exogenous bacteria by microbial aggregates and provides implications to bioaugmentation.</p> <p> </p> <p><strong>References:</strong></p> <ol> <li>Wu, Y., Zaiden, N., Liu, X., Mukherjee, M. and Cao, B., 2020. Responses of Exogenous Bacteria to Soluble Extracellular Polymeric Substances in Wastewater: A Mechanistic Study and Implications on Bioaugmentation. Environmental Science & Technology. In press</li> <li>Wu, Y., Cai, P., Jing, X., Niu, X., Ji, D., Ashry, N.M., Gao, C. and Huang, Q., 2019. Soil biofilm formation enhances microbial community diversity and metabolic activity. Environment international, 132, p.105116.</li> </ol>

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