Search

Biofilms are the predominant habitat of microbes in aquatic ecosystems. The environment in the biofilm is a nutrient-rich microhabitat that contains many types of ions. These nutrient-rich microhabitats are formed through the adsorption and desorption processes of ions. Hence, ion adsorption and desorption characteristics are essential to understanding and using biofilms for various purposes, such as aquatic environmental purification technology. However, the characteristics of ion desorption from biofilms after adding ions, especially cations, have yet to be widely explored. This study aims to analyze the ion desorption characteristics of the biofilm before and after the addition of monovalent dan divalent cations (i.e., K⁺ and Mg²⁺). The samples were biofilm formed naturally in the Lahor Reservoir in Malang Regency, East Java, Indonesia. The results of this study indicate that the ions will be desorbed from the biofilm matrices when the concentration of these ions around the biofilm decreases. Ions desorbed from biofilm matrices are K⁺, NH₄⁺, Na⁺, Ca²⁺, and Mg²⁺. When the concentration of cations in the surrounding water of the biofilm increases, various ions are desorbed from biofilms while the cation is adsorbed into the biofilm matrices. This study shows that the ions with a greater tendency to be desorbed from the biofilm have the same valence as the added ion. The results of this study indicate that one of the main factors driving ion desorption from the biofilm is the similarity of the characteristics with the ions adsorbed into the biofilm matrix. According to the results of this study, biofilm matrices can play an essential role in shaping ion dynamics in aquatic ecosystems and become one of the critical foundations for understanding aquatic microbial ecology and developing biofilm-based eco-aquatic technology. [ABSTRACT FROM AUTHOR]

Diclofenac is a non-steroidal anti-inflammatory drug, commonly detected in natural aquatic environments around the world. This persistent bio-refractory emerging contaminant often occurs in concentrations of ecological significance leading to several physiological implications in living organisms. In this study, diclofenac was degraded by bacterial pure cultures isolated from soil, following which the degradation efficiency was enhanced using activated charcoal. Four bacterial strains were isolated and studied for degradation of 10 mg/L of diclofenac in the presence of acetate for 6 days. The contaminant removal was evaluated using High Performance Liquid Chromatography (HPLC). Diclofenac degradation occurred through co-metabolism with acetate acting as a supplementary carbon source. This degradation was further augmented using 1g/L commercial activated charcoal, which increases the removal efficiency through adsorption. A control consisting of only activated charcoal was also kept to check removal through adsorption without involving bacterial degradation. The control containing activated charcoal showed a removal efficiency of 71.36% through adsorption, whereas bacterial strains A, B, C, and D exhibited removal efficiencies of 86.73%, 80.83%, 77.77%, and 86.06% respectively. On combining activated charcoal with bacterial isolates, these removal efficiencies were considerably improved to 92.34%, 86.38%, 82.6%, and 93.31% respectively. This study will extend the understanding regarding the combination of two different removal methods pertaining to conventional physicochemical and biological treatment. [ABSTRACT FROM AUTHOR]

Vaginal microecology is a very sensitive and complex system in the human body system, which is affected by various factors. In such a special physiological period of pregnancy, the levels of autoimmunity and hormones fluctuate, and the vaginal microecology during pregnancy is easy to change, which leads to a variety of adverse pregnancy outcomes. This study summarizes the analysis and opinions on the vaginal microecological status of pregnant women so far, and clarifies the changing characteristics and influencing factors of vaginal microenvironment during pregnancy. The relationship between vaginal microecological changes during pregnancy and different pregnancy outcomes was reviewed. [ABSTRACT FROM AUTHOR]

Escherichia coli (E. Coli) is a fecal coliform bacteria found in the digestive systems of livestock and humans. Pathological strains of E. Coli are known to cause foodborne illness globally. Previous research on local Anderson, South Carolina streams identified the presence of E. coli with the H7 flagella indicative of the E. Coli O157:H7 strain which is of particular concern. This research was Western Blot based using an antibody against the H7 flagella protein. Our project utilized the SC Adopt-A-Stream protocols to sample the Rocky River and Cox Creek in Anderson using 3M Petrifilm E. coli/Coliform Count Plates to quantify overall E. coli levels. Individual colonies that identified as E. coli through the Petrifilm plates were selected for further characterization. Genomic DNA was purified from the colonies and sent for 16s rRNA Gene Sequencing (V1 to V9 regions) for bacterial identification. Several of the putative E. coli colonies were subsequently identified as other bacterial species by these sequencing-based methods including Raoultella planticola and multiple Shigella species. This genetic sequence data allows for phylogenetic characterization of the bacterial species isolated, and a more detailed understanding of the microbial environment of these bodies of water. [ABSTRACT FROM AUTHOR]

The models of microbial system have a history that includes research in various fields of evolution, ecology and more recently optimization algorithms (we refer there especially the mimetic bacterial growth algorithm). The growth of bacteria population in bioreactors is made often using mathematical models as premises for optimization and control. Food webs and microbial food chains are subject of models by differential equations. The tool proposes to use the most common representation of the microbial systems, a two layered mechanism as a cascade of two biological reaction where one substrate is the subject of consumer by one microorganism that serves a limiter substrate for the second microorganism. The system modeled by system of differential equations call the Matlab solver for numerical solutions. The user has the possibility to use predefined constants, user-defined constants or optimized ones for stability analysis. A second module that are implemented in the main program deals with more recent approach, the three-layered ‘food-web’, where a third organism is added to model. The model can test the influence of growth organisms as interaction between multiple species. The user has the possibility to create the system of equation using a Constructor Builder. The parser from this module will translate the text-code in an .m file callable from Matlab as system used be ODE solver. The visualization module displays in a GUI (Graphic User Interface) the result of simulation. The tool is useful for understanding and prediction of microbial colony growth but also offer a perspective for future development of additional modules for microbial ecology. [ABSTRACT FROM AUTHOR]

A mathematical model is proposed to investigate the effect of microgravity on biofilm growth. We examine the case of biofilm suspended in a quiescent aqueous nutrient solution contained in a rectangular tank. The bacterial colony is assumed to follow logistic growth whereas nutrient absorption is assumed to follow Monod kinetics. The problem is modeled by a coupled system of nonlinear partial di_erential equations in two spatial dimensions solved using the Discontinuous Galerkin Finite Element method. Nutrient and biofilm concentrations are computed in microgravity and normal gravity conditions. A preliminary quantitative relationship between the biofilm concentration and the gravity field intensity is derived. [ABSTRACT FROM AUTHOR]

This paper investigates C3H7NO2S (Cysteine) effect on the inhibition of reinforcing steel corrosion in concrete immersed in 0.5 M H2SO4, for simulating industrial/microbial environment. Different C3H7NO2S concentrations were admixed, in duplicates, in steel-reinforced concrete samples that were partially immersed in the acidic sulphate environment. Electrochemical monitoring techniques of open circuit potential, as per ASTM C876-91 R99, and corrosion rate, by linear polarization resistance, were then employed for studying anticorrosion effect in steel-reinforced concrete samples by the organic hydrocarbon admixture. Analyses of electrochemical test-data followed ASTM G16-95 R04 prescriptions including probability distribution modeling with significant testing by Kolmogorov-Smirnov and student's t-tests statistics. Results established that all datasets of corrosion potential distributed like the Normal, the Gumbel and the Weibull distributions but that only the Weibull model described all the corrosion rate datasets in the study, as per the Kolmogorov-Smirnov test-statistics. Results of the student's t-test showed that differences of corrosion test-data between duplicated samples with the same C3H7NO2S concentrations were not statistically significant. These results indicated that 0.06878 M C3H7NO2S exhibited optimal inhibition efficiency η = 90.52±1.29% on reinforcing steel corrosion in the concrete samples immersed in 0.5 M H2SO4, simulating industrial/microbial service-environment. [ABSTRACT FROM AUTHOR]

In post-mining areas appearance of uncontrolled mining gas exhalations can be observed. Methane migrating through the strata, together with soil air may create explosive mixtures. Occurrences of mining gases are caused due to discontinuation of water pumping process in abandoned mines and fast rising and restoration of water table. However, it's not obvious, that all hydrocarbons in soil pores come from abandoned hard coal mines. Often in soil pores mixtures of microbial and thermogenic gases are observed. For identifying hydrocarbons origins isotopic methods are commonly used. In this article methodology of soil gas collected was presented. Author showed equipment used to surface geochemistry measurements. Short brief of atmogeochemist probes available on market was done. Pros and cons were pointed out. Shallow wells construction was discussed as well as problems which take a place during measurements. Measurement plan and grid in different investigation localization were discussed. Author also made literature review of previous Polish experiences of gas migration. [ABSTRACT FROM AUTHOR]

Research of the optimum concentration of sulfuric acid (H2SO4) on acid hydrolysis and enzyme at the optimum dosage of enzyme hydrolysis of newspaper waste in producing hydrolyzate at optimum levels in reducing sugars and fermentation of its hydrolyzate was conducted. The purpose of this study was to obtain the optimum enzyme dosage and concentration of sulfuric acid hydrolysis of waste paper to produce the best reducing sugar hydrolyzate and microbes to obtain the most effective use of microbial fermentation process. Descriptive and experimental method were used in this research. Descriptive method was applied for evaluating enzyme and acid hydrolysis, preparation hydrolyzate and starter of culture as well as fermentation. The fermentation was conducted by experimental methods using Completely Randomized Design (CRD) with three replications. This study parameter included reducing sugar content, ethanol content, microbial population, Dextrose Equivalent (DE) and pH. Our finding showed that the highest reducing sugar content on sulfuric acid hydrolysis (H2SO4) was at a concentration of 6, whereas the liquefaction α-amylase enzyme was at dosage 0.52 μL ∙ g-1. The optimum dosage for the hemicellulase enzyme hydrolysis was at 0.001 g ∙ g-1, whereas the saccharification cellulase and amyloglucosidase enzyme were 0.83μL ∙ g-1 and 0.56μL ∙ g-1. The most effective and optimum microbial fermentation process was obtained with a consortium of Zymomonas mobilis and Pichia stipitis that produces the highest ethanol content by 6.523 % at 72 h with fermentation efficiency by 45.77 %. Consortium Zymomonas mobilis and Pichia stipitis also reached the highest end of exponential population phase with 27.5 × 1 010 CFU at 36 h with the highest maximum growth rate by 2.48. Additionally the effectiveness was also supported by the lowest reducing sugar content at 9.09 % with the highest growth yield by 1.689 and the end of Dextrose Equivalent (DE) by 56.140 at the lowest pH of 3.34. [ABSTRACT FROM AUTHOR]

Biodegradation in porous media is most often the consequence of coupled transport phenomena in the presence of biofilms. The description of such transport problems involves different scales: the bacteria scale, the scale of a locally homogenized biofilm, heterogeneous biofilms at a scale lower than the pore-scale, the pore-scale problem, the Darcy-scale description, and, possibly, subsequent scales corresponding to heterogeneities effects. In this paper, various upscaling problems are reviewed. Different models may be built, depending on the amount of local non-equilibrium included in the analysis: equilibrium models, multiple-equations models, asymptotic models. These different models feature different effective properties, which can be estimated from real data through the resolution of several “closure problems” linking averaged variables and lower-scale deviations. The relevance of these different models is discussed based on some theoretical analysis and direct numerical simulation. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa is an opportunistic pathogen that grows as a biofilm on implanted medical devices1. Attachment, colonization and biofilm formation are regulated by bacterial quorum sensing (QS)2. Naturally derived compounds (e.g. essential oils) with QS inhibitory activity have shown good pathogen control3. We applied surface treatment strategies with an oil extract from cinnamon, cinnamaldehyde, in electrospun fibres that inhibited biofilm formation. [ABSTRACT FROM AUTHOR]

Biofilms formed on the submerged part of reed and stone surface contained various types of microorganisms, such as eukaryotes, heterotrophic and autotrophic bacteria. Culturable bacteria from biofilms of reed and stone surface were classified into wide range of phylogenetic groups. It was also found that light irradiation affect the mineralization activity of these biofilms. [ABSTRACT FROM AUTHOR]