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Copyright of Romanian Journal of Materials / Revista Romana de Materiale is the property of Foundation for Materials Science & Engineering Serban Solacolu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

ZnSe, ZnSe-TiO2 microspheres and nanostructured TiO2 obtained by hydrothermal and sol–gel methods were tested against Staphylococcus aureus ATCC 25923 and Micrococcus lysodeikticus ATCC 4698 before and after lysozyme (Lys) loading. Morphological characterization of inorganic matrices and hybrid organic–inorganic complexes were performed by microscopy techniques (SEM, AFM and Dark Field Hyperspectral Microscopy). Light absorption properties of ZnSe, ZnSe-TiO2 and TiO2 powders were assessed by UV–visible spectroscopy and their ability to generate reactive oxygen species (•OH and O2•−) under visible light irradiation was investigated. Antibacterial activity of ZnSe, ZnSe-TiO2, TiO2, Lys/ZnSe, Lys/ZnSe-TiO2 and Lys/TiO2 samples under exposure to visible light irradiation (λ > 420 nm) was tested against Staphylococcus aureus and Micrococcus lysodeikticus and correlated with ROS photogeneration. [ABSTRACT FROM AUTHOR]

In this preliminary screening, we assessed the antibacterial activity of in vitro obtained plant material, namely shoots of Artemisia eriantha (Asteraceae) and callus of Ocimum basilicum L. var. 'Spicy globe', against two bacteria strains, the Gram-positive ones including Staphylococcus aureus ATCC 25923, and Gram-negative, Escherichia coli ATCC 25922 by the plate-counting method. Artemisia sprouted on the Murashige-Skoog medium added with 1.5 mg/L benzylaminopurine and 'Spicy globe' basil developed callus on Murashige - Skook basal medium supplemented with 2.5 mg/L naphtylacetic acid (NAA). The method of using small pieces of vegetal material inoculated in Erlenmeyer flasks on liquid Luria-Bertani medium added with standardized microbial cell suspension was not effective against the pathogenic bacteria in the case of the Artemisia species, but the same method was efficient for basil cultivar 'Spicy globe'. [ABSTRACT FROM AUTHOR]

This study analyzed the metabolic potential of some functional groups of bacteria in aquatic urban systems and evaluated the abundance of communities of total heterotrophic bacteria in the water in relation to the monitored physico-chemical factors. The results obtained showed seasonal differences, especially in spring. The high values of the abundance of heterotrophs in winter are related to human activity at the sampling stations. Screening for four types of extracellular hydrolytic enzyme with potential for degradation of organic matter (amylases, lipases, proteases and cellulases) led to the conclusion that lipolytic bacteria were dominant in the studied ecosystems, while proteolytic bacteria were observed in low numbers, but were present in urbanized areas. The presence of cellulolytic bacteria is correlated with the development of macrophytic vegetation. The aim of the present study was oriented towards the evaluation of the anthropogenic input in several lakes surrounding Bucharest in the Nord-Eastern region. These urban ecosystems are generated as a requirement of city development. The microbiological and general enzymatic approaches generated some novel results concerning the pollution degree of aquatic urban ecosystems and could be considered as a platform for further investigation. [ABSTRACT FROM AUTHOR]

Copyright of Romanian Journal of Materials / Revista Romana de Materiale is the property of Foundation for Materials Science & Engineering Serban Solacolu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The present paper deals with the seasonal dynamics of microbial communities in Letea saline lake which is located nearby of the village with the same name by classical microbiological methods. The chloride content is variable, with values from 8.9 g/L (spring of 2018) up to 38.3 g/L (autumn of 2017). There are different similarities between the values obtained over seasons. Thus, in the spring of 2017, an average of 11.8 g/L was obtained, a value close to that obtained in the spring of 2018 (8.9 g/L). The average of chlorides in autumn 2016 (25.5 g/L) is relatively different to the autumn of 2017 (38.3 g/L). During the autumn of 2016 and spring of 2018, the dynamics of several microbial communities was assessed as follow: heterotrophic, sulphate reducing, ammonifying and denitrifying bacteria respectively. The recorded results revealed that the best represented communities appear to be ammonifying bacteria, being high in the spring months. Denitrifying bacteria have registered high values in autumn 2017 and sulphate reducing bacteria in April 2017. The dynamics of halophilic bacteria were also recorded and more than 100 strains were randomly selected for purification, characterization and extracellular enzymatic activity analyses for the future biotechnological applications. [ABSTRACT FROM AUTHOR]

The present study reveals the influence of the culture medium composition on decarboxylase production by a strain of halotolerant bacteria isolated from the Letea salt lake in the Danube Delta, namely strain LN 1-17, the purification of the enzyme obtained on the culture medium that offers optimal conditions for its production, as well as the enzyme characterization. The results of this study confirm that the investigated strain harbors the capacity to produce lysine decarboxylase. Related to the influence of culture medium composition the best result was recorded on MH medium supplemented with lysine and casamino-acids. The purification of the enzyme by precipitation with acetone followed by gel filtration was considered appropriate due to the increase of the enzymatic specific activity even if it has led to a decrease in the protein content. The biochemical characterization of the enzyme showed an optimal activity at neutral pH (7), in the absence of NaCl and at a temperature of 60°C. [ABSTRACT FROM AUTHOR]

The waste glycerol representing the main secondary product in biodiesel industry is obtained in large amounts whose storage raise environmental problems. The bioconversion of this product to other product by various microorganisms represents a convenient alternative. Several enzymes are involved in waste glycerol conversion and among these the lipase has a great biotechnological importance. This work deals with the isolation, purification and kinetic characterization of lipase from moderately halophilic and halotolerant strains, namely Marinococcus halophilus JCM 2472 and strain S3-6. The purified enzyme showed catalytic activity at pH 8-10 and in a wide range of temperatures between 15 and 70 °C with optimum at values over 60 °C. The data recorded for the effect of sodium chloride content revealed the halotolerant character of the investigated enzymes with optimum activity at 1 M NaCl and being active between 0 and 3 M. The concentration of the substrate i.e. olive oil, sun-flower oil, has no effect on the lipase activity. The cultivation conditions of the microbial strains and the effect of culture media composition for obtaining the enzyme are also presented in this study. [ABSTRACT FROM AUTHOR]

Copyright of Oltenia, Studii si Comunicari Seria Stiintele Naturii is the property of Museum of Oltenia Craiova and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Romanian Journal of Materials / Revista Romana de Materiale is the property of Foundation for Materials Science & Engineering Serban Solacolu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chemically, biodiesel is obtained from the trans esterification of vegetable oil or animal fat, in the presence of alcohol, such as methanol or ethanol, generating glycerol as by product. The aim of this work was to test the capacity of several halophilic microorganisms to grow on culture media supplemented with waste glycerol, derived from different sources (Mediaş and Slobozia), and to produced lipases and decarboxylases used as biocatalysts to convert residual glycerol to valuable compounds. From a total of 30 halophilic bacterial strains, isolated from Balta Albä, Buzäu County, and Techirghiol salt lakes, a number of eight halophilic/halotolerant strains showed lipolytic activity. Marinococcus halophilus strain JCM 2472, a moderately halophilic bacteria, was used in this study for its capacity to synthesized extracellular lipases and decarboxylases. [ABSTRACT FROM AUTHOR]

Since most industrial processes are characterised by harsh physicochemical conditions that rapidly inactivate enzymes from mesophiles, current studies are geared towards the detection of extremophilic microorganisms producing enzymes that exhibit optimal activities in extreme ranges of salt concentration, temperature and pH. Halophilic microorganisms are an important source of salt-tolerant hydrolytic enzymes that can be used in bioremediation processes and in various biotechnological applications. In this context, the aim of our research is to screen the halophilic microorganisms producing hydrolases, isolated from the Atacama Desert, the driest and oldest desert on Earth. In order to isolate halophilic microorganisms, suspensions of salt crystals from the Atacama Desert in dilute salt solutions were inoculated on growth media like MH, JCM168, YGC, MEA and BG11. Screening of isolates for extracellular hydrolases (amylase, protease, cellulase, lipase, inulinase, pectinase) was performed on different assay media supplemented with specific substrates (starch, casein, carboxymethyl cellulose, Tween 80, inulin, pectin). Some isolates were selected with respect to their potential of producing hydrolases and studied in detail. The results of the present study represent a preliminary, but essential, step to identify novel biological sources of salt-tolerant enzymes, which would be of great importance particularly in biotechnology. Further investigations should be directed towards the biochemical characterization of these extremozymes and the cloning of encoding genes in order to elucidate the salt tolerance mechanisms and to obtain the best hydrolases producers, respectively. [ABSTRACT FROM AUTHOR]

This paper presents preliminary results of an investigation that had as main objective to quantify the seasonal variations of halophilic bacteria in the saline Lake Letea (Romania), which has an alkaline pH and a salt (chloride) concentration that varies in time, and their ability to produce extracellular hydrolytic enzymes. The investigations were performed from October 2016 until May 2018. Numbers of cultivable putative moderately halophilic bacteria were estimated using culture medium MH with 10% NaCl. The recorded number of colony forming units/mL was between 41 (October 2016) and 3.7x103 (April 2017). After a random selection, colonies were grown for three successive passages for purification, and 82 isolates were investigated. Based on their salt requirement and tolerance, 69 isolates were halotolerant and 13 isolates were moderately halophilic bacteria. The generation time was also determined for several isolates. Seventeen percent of the isolates were oxidase-negative and 83% oxidase-positive. Forty eight percent of isolates were catalase-negative and 52% catalase-positive. Presence of extracellular enzymatic activities was tested using MH medium with salinity varying between 0-4 M and supplemented with a substrate to induce the production of the hydrolases tested. The highest hydrolytic activities were recorded for Tween 80, casein and inulin. This study represents a preliminary investigation of the diversity and extracellular enzymatic activities of halophilic bacteria isolated from Lake Letea. [ABSTRACT FROM AUTHOR]

The Humor Monastery located in Suceava County, Romania has been included since 1993 in the UNESCO heritage, as a cultural site. Due to the presence of efflorescences and improper microclimate conditions for conservation, pink pigmented areas showed on the wall surface, both in the prenave of the monastery and in the Burial Chamber, up to a height of 0,7 m from the ground. The aims of the present study were to establish the origin of pink pigmentation and to test colloidal solutions of gold and silver nanoparticles in order to establish a decontamination strategy for the affected areas and a treatment to prevent future colonisations. Moderately halophilic and halotolerant bacterial strains were isolated from samples of infilling mortar. They were morphologically characterised by optical microscopy and SEM, tested for salinity, pH and temperature optimal values for growth, enzyme synthesis, antibiotic susceptibility and capacity to form biofilms. The pigments produced by the isolated bacterial strains were extracted for FT-IR analysis, and some vegetal origin colloidal silver and gold nanoparticle solutions were tested for their inhibitory effect on the biodeteriogens growth. Based on the results obtained we suggest a bacterial origin of the pink discoloration responsible for the biodeterioration process in Humor Monastery. The efficiency of silver nanoparticles, obtained from white strawberry callus extract, in inhibiting the growth of carotenoid-producing halotolerant strains recommends them for decontamination treatment and for incorporation into infilling mortars used in restoration in order to prevent the biodeterioration process. [ABSTRACT FROM AUTHOR]

Saline environments are widely distributed in the world as a consequence of the geological steps in the evolution of the Earth. A lot of saline lakes and salt deposit are also found on the Romania territory, the most representative being Ursu Lake, complex of saline lakes in Slanic Prahova or Ocna Sibiului and Salt Lake (Braila County). The salt deposits on the Romania territory have geological age from the periods of Triassic (in Moesic platform - south of Romania) and Miocene (Transylvania and Maramures areas). Over 300 salt massifs were identified in- or extra-Carpathian areas and in some places (Slanic Prahova, Praid, Sarata Monteoru) piercing the Earth in the form of salt „mountains” (Ciobanu, 2002). This work will be focused on the main results obtained in our laboratories in last years and the main investigated saline ecosystems will be presented. The studies on the salt lake complex and from salt deposit from Slanic Prahova area conducted to the isolation of a novel haloarchaea strain, namely Haloferax prahovense and have highlighted some relationship between microbial composition in lakes and deposit. Recently investigated saline lake Letea, located inner Danube Delta revealed a seasonally variable salinity of this ecosystem which is reflected in microbial communities not only halophilic one, but also involved in main biogeochemical cycles of nitrogen and sulphur. On the other hand, the halophilic microorganisms belonging to Garicola genus have been isolated from so called „unusual habitat for halophiles”, namely mural painting from refectory of Hurezi Monastery. [ABSTRACT FROM AUTHOR]