scholarly journals Effect of Interstitial Velocity on the Adsorption of Bacteria onto Soil

2005 ◽  
Vol 23 (7) ◽  
pp. 535-542 ◽  
Author(s):  
Jamal Abu-Ashour ◽  
Majed Abu-Zreig

The adsorption of bacteria onto soil is affected by the physical and chemical characteristics of the soil and water, the size and morphology of the bacterial cells, and the water-flow characteristics in the soil. The present study focuses on the latter factor by investigating the effect of the interstitial velocity on the adsorption of bacteria onto soil. Columns of 10 cm diameter and 130 cm height, respectively, were packed with a sandy soil. The columns were saturated with water containing nalidixic acid-resistant Escherichia coli as a bio-tracer at three different pH levels. The columns were maintained at 20°C for 24 h before connecting the column outlet to its inlet by a pump in a closed loop. Water containing the biotracer was re-circulated through the column for another 24 h at three different interstitial velocities. Water samples were taken from a sampling tap connected to the pump at 4-h intervals. These samples were analyzed to determine the biotracer concentration. The results show that more biotracer cells were retained in the soil at the lower interstitial velocity. The higher interstitial velocity resulted in higher shear forces which caused more desorption of the biotracer cells from the surfaces of the soil particles. Bacterial adsorption was higher at the acidic pH value. The survival of the biotracer cells in soil solution was also tested at three different pH levels. The results show that no decline in the biotracer concentration occurred during the test period.

Nanomaterials ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 1463 ◽  
Author(s):  
Vishma Pratap Sur ◽  
Marketa Kominkova ◽  
Zaneta Buchtova ◽  
Kristyna Dolezelikova ◽  
Ondrej Zitka ◽  
...  

The physical and chemical synthesis methods of quantum dots (QDs) are generally unfavorable for biological applications. To overcome this limitation, the development of a novel “green” route to produce highly-fluorescent CdSe QDs constitutes a promising substitute approach. In the present work, CdSe QDs were biosynthesized in yeast Saccharomyces cerevisiae using a novel method, where we showed for the first time that the concentration of tryptone highly affects the synthesis process. The optimum concentration of tryptone was found to be 25 g/L for the highest yield. Different methods were used to optimize the QD extraction from yeast, and the best method was found to be by denaturation at 80 °C along with an ultrasound needle. Multiple physical characterizations including transmission electron microscopy (TEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and spectrophotometry confirmed the optical features size and shape distribution of the QDs. We showed that the novel conjugate of the CdSe QDs and a cell-penetrating peptide (hecate) can detect bacterial cells very efficiently under a fluorescent microscope. The conjugate also showed strong antibacterial activity against vancomycin-resistant Staphylococcus aureus (VRSA), methicillin-resistant Staphylococcus aureus (MRSA), and Escherichia coli, which may help us to cope with the problem of rising antibiotic resistance.


1984 ◽  
pp. 375-382
Author(s):  
S. M. Fournier ◽  
M. L. Sentis ◽  
B. M. Forestier ◽  
B. L. Fontaine

Author(s):  
Rizal Awaludin Malik ◽  
Nilawati Nilawati ◽  
Novarina Irnaning Handayani ◽  
Rame Rame ◽  
Silvy Djayanti ◽  
...  

The methods of microbial cells preservation were already known by liquid drying, freeze-drying, and freezing. Those methods could preserve bacteria cells in a long period of time but its survivability was relatively low and used relatively high energy during preservation. Immobilization was known as entrapping, attaching or encapsulating bacterial cells in a suitable matrix. This research was conducted to know the suitability of zeolite as immobilization carrier and also as preservation matrix of two halophilic archaea Haloferax chudinovii and Haloferax lucentense. Variable of this research was the type of the carrier which was raw zeolite, 110oC and 300oC heat-activated zeolite carrier, parameters measured in this study was physical and chemical of zeolite such as chemical content, Si/Al ratio, surface area and pore volume, and biochemical assay, bacterial cells numbers after immobilization and bacterial cells after preservation as bacterial response to the immobilization and preservation. Heat activation was significantly affecting the chemical composition, carrier surface area, and pore volume. Highest surface area, pore volume, and Si/Al ratio were obtained in 110oC pretreated zeolite followed by 300oC pretreated zeolite. The bacterial cells obtained after immobilization process was 1,8x107 cfu/g, 3,0 x 107 cfu/g, and 2,1x107 for raw zeolite, 110oC pretreated zeolite and 300oC zeolite respectively. After 4 months preservation, the slight reduction of the bacterial cells was observed. Immobilization halophilic archaeae using zeolite as carrier was proven as low cost and effective preservation method due to relatively simple process and unspecific preservation temperature requirements.


Author(s):  
Hari Hariadi ◽  
Marleen Sunyoto ◽  
Bambang Nurhadi ◽  
Agung Karuniawan

The purpose of this study was to obtain maltodextrin with the appropriate concentration of purple sweet potato anthocyanin extract to produce the natural dye powder preparations with the best physical and chemical characteristics. The research method used is Experimental Method (Experimental Method) by using Group Random Design (GRD). The experiment consisted of three treatments and each was repeated four times, with the treatment obtained in cassava purple with a concentration of 35.4 mg / 100gr anthocyanin extract.  The  next  stage  was  to  determine  the  best  concentration  of  maltodextrin Consisting of four treatments and each repeated three times. The anthocyanin pigment powder of purple sweet potato with various treatments of maltodextrin concentration addition gave a significant effect on the soluble time, and yield, but did not gave a significant effect on total of anthocyanin, hygroscopicity and solubility. The treatment 10% of maltodextrin concentration addition resulted in best characteristic with total anthocyanin of 48.43 mg / L, color intensity L * (brightness) of 37.86, a * (redness) of 43.66, b * (yellow) of 21.68, water content of 5.56%, hygroscopicity of 11.62%, solubility of  97.13%, soluble time of 159 seconds, pH value of 3.04, and yield of 31.38%. The resulting anthocyanin powder shows that the anthocyanin pigment powder of purple sweet potato with the maltodextrin concentration addition has the potential to serve as a natural dye powder for food and beverages.


Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Zhigang Zeng ◽  
Xiaoyuan Wang ◽  
Bramley J. Murton ◽  
Haiyan Qi ◽  
Berit Lehrmann ◽  
...  

The composition of hydrothermal plumes reflects the physical and chemical characteristics of seafloor hydrothermal fluids, which in turn reflects the host rock and subseafloor reaction conditions as well as the water column processes that act to alter the plumes as they disperse and age. Here, we show that the turbidity, current, pH value, dissolved Fe (dFe), and dissolved Mn (dMn) compositions of hydrothermal plumes can be used to understand the spatial distribution and source of hydrothermal systems in the submarine geological environment. Data were obtained from 18 hydrocast stations, among which the water column samples were collected at 8 stations during the MANUS cruise of R/V KEXUE in 2015. The results showed that the Satanic Mills plume and Fenway plume rose approximately 140 m and 220 m above the seafloor, respectively. In the Satanic Mills plume, dFe remained longer than dMn during lateral plume dispersal. There was a clear intersection of the Satanic Mills plume and Fenway plume between 1625 m and 1550 m in the PACMANUS hydrothermal field, and the varied dispersion trends of the mixed plumes were affected by current velocities at different depths. The physical and chemical properties of the seawater columns in the Manus Basin were affected by the input of high-Mn, high-Fe, and low-Mg vent fluids. The turbidity and dFe, dMn, and dissolved Mg concentrations in the sections of the plumes proximal to the Satanic Mills, Fenway, and Desmos vent sites were generally higher (turbidity, Mn, and Fe) and lower (Mg) than those in the sections of the plumes that were more distal from the vent sites. This implied that the plumes proximal to their vent fluid sources, which were interpreted to have relatively young ages, dispersed chemically over time, and their concentrations became more similar to those of the plumes that were more distal from their vent fluid sources.


2019 ◽  
Vol 110 ◽  
pp. 01037 ◽  
Author(s):  
Igor Kharchenco ◽  
Vyacheslav Alekseev

The effect of the pH of the reaction solution on the crystallization process and the ettringite morphology is theoretically substantiated and experimentally proved. Using physical and chemical research methods, the dependence of the morphology of crystallizing ettringite on the pH value of the reaction solution was established. It has been established that by introducing mineral micro fillers into the composition of expanding cement, it is possible to actively influence the pH value, the morphology of the resulting ettringite, the expansion kinetics, and the strength of cement stone and concrete based on it. The studies of the technical properties of concrete on the basis of expanding cements of various types have shown that with the introduction of micro fillers into the concrete composition, which intensify volume expansion during hydration of cement stone at the building site or factories for the production of ready-mixed concrete, it is possible to control the kinetics and extent of expansion, expansion pressure, deformative and strength characteristics of concrete and reinforced concrete structures.


2019 ◽  
Vol 944 ◽  
pp. 1144-1151
Author(s):  
Lin Yan Zhao ◽  
Yue Gang Shen ◽  
You Shu Fan ◽  
Li Wen Ma ◽  
Xiao Li Xi

As a cheap and stable transition metal oxide, tungsten trioxide (WO3) has received extensive attentions due to superior physical and chemical properties that could be used in electronic devices, lithium-ion batteries, gas sensors, dye sensitized solar cells, catalysts. In this study, the well-designed 1D architecture of nanowires and nanorods was successfully synthesized via a simple and facile solvethermal method with no template or additives. It is found that both solvent type and concentration of W raw material can affect the size and morphology of WO3significantly in a regular way. Different products showed distinct photocatalytic activities during the processing of degradation methylene blue under visible light, and the underlying reasons for the different photocatalytic activities were discussed.


2009 ◽  
Vol 71-73 ◽  
pp. 449-452
Author(s):  
G. Gu ◽  
Li Jun Su ◽  
Guan Zhou Qiu ◽  
Y. Hu

Acidithiobacillus caldus and Leptospirillum ferriphilum cells grown in different energy substances (ferrous ion, sulfur and pyrite) were used. The adhesion of A. caldus and L. ferriphilum cells on pyrite and their effect on pyrite surface properties were studied by adsorption, zeta-potential and FT-IR methods, and the corrosion images of pyrite interaction with bacteria were examined using atomic force microscopy. Research showed that pyrite isoelectric point (IEP) after interaction with bacterial cells shifted towards cells isoelectric point, and the shift degree in case of interaction with A. caldus was observed to be much more pronounced than for interaction with L. ferriphilum, which can be due to higher affinity of A. caldus towards pyrite. The FT-IR spectra of pyrite treated with bacterial cells revealed the presence of the cell functional groups signifying cells adsorption. Although the adsorption density of A. caldus on pyrite was higher than that of L. ferriphilum, L. ferriphilum with strong ability to oxidize ferrous ion showed better leaching efficiency than A. caldus with strong ability to oxidize sulfur for pyrite leaching. The results demonstrated that more important of indirect action (L. ferriphilum) than direct action (A. caldus) on pyrite.Introduction Bacterial adsorption to minerals is an initial step in bacterial leaching for metal recovery [1]. It has been reported that bacterial adhesion is dependent not only on the biochemical properties of the organism but also on the interfacial properties of the various interfaces existing in a bioleaching system[2].The bacteria-mineral interactions result in the changes of their surface properties. The elucidation of their alternate will be beneficial for bioleaching processes. Both Acidithiobacillus caldus and Leptospirillum ferriphilum are known for their ability to inhabit acidic environments and derive energy from oxidation of inorganic substances with natural occurrence in ore deposits and acid mine drainage and high affinity towards sulfide minerals [3-5]. In this work, the alterations of surface properties of pyrite after interaction with L. ferriphilum and A. caldus are studied, and the changes in surface properties caused by bacterial adsorption are discussed with reference to bioleaching behavior of pyrite.


2011 ◽  
Vol 281 ◽  
pp. 223-227 ◽  
Author(s):  
Jun Yin ◽  
Ju Kui Zhang ◽  
Lei Wu ◽  
Xin Li

Choose three kinds of clean drinking water distilled water, tap water, mineral water for the object, study the impact of magnetization on water’s conductivity, pH value, ORP and the solubility of insoluble salts by experiment of magnetic field intensity 500mT and different time, the results showed that magnetic treatment can improve the conductivity, pH of three kinds of water samples, lower ORP value, and has a certain significance on human health, but it is limited in improve the solubility of insoluble salts with the characterization of calcium carbonate.


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