Guven Ozdemir

Heavy metal biosorption by biomass of Ochrobactrum anthropi producing exopolysaccharide in activated sludge

The removal of chromium, cadmium and copper, toxic metals of high environmental priority due to their toxicity, from dilute aqueous solutions has been studied in the present work, applying a dead exopolysaccharide producing bacterium, Ochrobactrum anthropi, isolated from activated sludge. Particularly, the effect of pH, metal concentration and the effects of contact time were considered. Optimum adsorption pH values of chromium(VI), cadmium(II) and copper(II) were 2.0, 8.0 and 3.0 respectively. Experimental results also showed the influence of initial metal concentration on the metal uptake for dried biomass. Both the Freundlich and Langmuir adsorption models were suitable for describing the short-term biosorption of chromium(VI), cadmium(II) and copper(II) by O. anthropi.

Metal biosorption capacity of the organic solvent tolerant Pseudomonas fluorescens TEM08

Many kinds of biomass are being tested as a biosorption material for metal removal from the contaminated waters. In the present study the biosorption capacity of an organic solvent tolerant (OST) bacterium was investigated against Cr(VI) and Ni(II). The OST strain of Pseudomonas fluorescens TEM08 was isolated from an oil contaminated soil sample and grown in normal culture conditions (type I) and in the presence of the cyclohexane (type II). Two types of cells were used in the biosorption experiments to compare the organic solvent effect on the biosorption capacity. The biosorption equilibrium was described by Langmuir and Freundlich adsorption isotherms. The value of Q(0) was higher for type I cells (40.8 for Cr(VI); 12.4 for Ni(II)) then the type II (40.7 for Cr(VI); 11.2 for Ni(II)). The adsorption capacity constants (K(F)) of Freundlich model for type I cells and for type II cells were 10.87 and 8.78 for Ni(II) and 13.60 and 10.99 for Cr(VI), respectively.

Effect of azithromycin, as an adjunct to nonsurgical periodontal treatment, on microbiological parameters and gingival crevicular fluid biomarkers in generalized aggressive periodontitis

UNLABELLED Emingil G, Han B, Özdemir G, Tervahartiala T, Vural C, Atilla G, Baylas H, Sorsa T. The effect of azithromycin, as an adjunct to nonsurgical periodontal treatment, on microbiological parameters and gingival crevicular fluid biomarkers in generalized aggressive periodontitis. J Periodont Res 2012; 47: 729-739.

Azithromycin as an Adjunctive Treatment of Generalized Severe Chronic Periodontitis: Clinical, Microbiologic, and Biochemical Parameters

BACKGROUND This study examines the efficacy of azithromycin in combination with non-surgical periodontal therapy on clinical and microbiologic parameters and gingival crevicular fluid (GCF) matrix metalloproteinases-8 (MMP-8) levels over 6 months in patients with severe generalized chronic periodontitis (CP). METHODS Twenty-eight of 36 patients with severe generalized CP were included in this randomized, double-masked, placebo-controlled, parallel-arm study. They were randomly assigned to azithromycin or placebo groups (500 mg, once daily for 3 days). Probing depth (PD), clinical attachment level, dichotomous presence or absence of supragingival plaque accumulation, and bleeding on probing were recorded. GCF samples were obtained from one single-rooted tooth with PD ≥ 6 mm, whereas microbiologic samples were collected from two single-rooted teeth with PD ≥ 6 mm. Microbiologic parameters were analyzed by quantitative real-time polymerase chain reaction for Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Fusobacterium nucleatum, Prevotella intermedia, and total bacteria. GCF MMP-8 levels were determined by immunofluorescence assay. RESULTS Azithromycin and placebo groups demonstrated similar but significant improvements in all clinical parameters (P <0.05). A. actinomycetemcomitans, P. gingivalis, T. forsythia, P. intermedia, and total bacteria significantly decreased over the 6-month period in both groups, whereas F. nucleatum was significantly reduced in all visits in the azithromycin group, with the levels also being lower compared with those of the placebo group (P <0.05). The azithromycin and placebo groups exhibited significant reduction in GCF MMP-8 levels at the post-treatment visit and at 2 weeks (P <0.05). CONCLUSION On the basis of the present findings, it can be concluded that adjunctive azithromycin provides no additional benefit over non-surgical periodontal treatment on parameters investigated in patients with severe generalized CP.

1,3-Propanediol production potential of Clostridium saccharobutylicum NRRL B-643

Owing to the significant interest in biofuel production in the form of biodiesel, vast amount of glycerol as a waste product is produced all over the world. Among the economically viable and ecologically acceptable solutions for the safe disposal of this waste, biotechnological conversion of glycerol into a valuable bioplastic raw material, namely 1,3-propanediol (1,3-PDO) seems to be very promising. In this study, 1,3-PDO production potential of Clostridium saccharobutylicum NRRL B-643 was studied and the results were compared with other types of anaerobic microorganisms (Clostridium spp., Pantoea agglomerans, Ochrobactrum anthropi, Chyreseomonas luteola, and Klebsiella pneumoniae) and aerobic microorganisms (Lactobacillus spp.). The results were important for understanding the significance of C. saccharobutylicum NRRL B-643 among other well-known 1,3-PDO producer species. According to the screening results only C. saccharobutylicum (B-643) was able to consume feed glycerol almost entirely. However, 1,3-PDO production yield was found to be 0.36mol/mol which is lower than that of Clostiridium beijerinckii (B-593). B-593 showed the highest value of production yields with 0.54 mol/mol. This microorganism is seen as a promising type for further 1,3-PDO studies, because it has the highest substrate utilization percentage among others. In this regard, this microorganism may have an important role in tolerating and converting glycerol during fermentation into 1,3-PDO.

Antimicrobial Activities of Volatile Components and Various Extracts of Dictyopteris membranaceae. and Cystoseira barbata. from the Coast of Izmir, Turkey

Abstract The methanol, dichloromethane, hexane, chloroform, and volatile components of Dictyopteris membranaceae. (Stackhouse) Batters (Dictyotaceae) and Cystoseira barbata. (Good et Woodw.) J. Agardh (Cystoseiraceae) were tested for their antimicrobial activities (four Gram-positive bacteria, four Gram-negative bacteria, and Candida albicans. ATCC 10239). Five compounds were identified in the volatile oil of D. membranaceae. accounting for >85% of the composition of the volatile oil. Twenty-eight compounds were identified in the volatile oil of C. barbata. accounting for >67% of the composition of the volatile oil. Major components were 6-butyl-1,4-cycloheptadiene (43.21%) for D. membranaceae. and docosane (7.61%) and tetratriacontane (7.47%) for C. barbata.. Many compounds in the volatile oil of C. barbata. were identified as hydrocarbon compounds. The volatile oils of these algae did not remarkably inhibit the growth of tested microorganisms. However, the hexane extracts showed more potent antimicrobial activity than methanol, dichloromethane, and chloroform extracts.

Extracellular polysaccharides produced by cooling water tower biofilm bacteria and their possible degradation

The extracellular polymers (EPS) of biofilm bacteria that can cause heat and mass transfer problems in cooling water towers in the petrochemical industry were investigated. In addition, these microorganisms were screened for their ability to grow and degrade their own EPS and the EPS of other species. Twelve bacteria producing the most EPS were isolated from cooling water towers and characterized biochemically by classic and commercial systems. These were species of Pseudomonas, Burkholderia, Aeromonas, Pasteurella, Pantoea, Alcaligenes and Sphingomonas. EPS of these species were obtained by propan-2-ol precipitation and centrifugation from bacterial cultures in media enriched with glucose, sucrose or galactose. EPS yields were of 1.68–4.95 g l−1. These EPS materials were characterized for total sugar and protein contents. Their total sugar content ranged from 24 to 56% (g sugar g−1 EPS), and their total protein content ranged from 10 to 28% (g protein g−1 EPS). The monosaccharide compositions of EPS were determined by HPLC. Generally, these compositions were enriched in galactose and glucose, with lesser amounts of mannose, rhamnose, fructose and arabinose. All bacteria were investigated in terms of EPS degradation. Eight of the bacteria were able to utilize EPS from Burkholderia cepacia, seven of the bacteria were able to utilize EPS from Pseudomonas sp. and Sphingomonas paucimobilis. The greatest viscosity reduction of B. cepacia was obtained with Pseudomonas sp. The results show that the bacteria in this study are able to degrade EPS from biofilms in cooling towers.

Candida albicans adherence on silicone elastomers: Effect of polymerisation duration and exposure to simulated saliva and nasal secretion

OBJECTIVES The surfaces of maxillo-facial prostheses made of silicone elastomers exposed to soft tissues may interact with saliva and nasal secretion. These body fluids may lead to colonisation of microorganisms on their surfaces leading to their degradation or infection. This study investigated Candida albicans adhesion onto commercial maxillo-facial silicone elastomers based on different polymerisation processes. METHODS Room-temperature polymerised maxillo-facial silicone elastomers (N=48) (10 mm x 10 mm x 2 mm) processed at different durations [VerSilTal VST-30 (20 min), VST-50 (12h overnight), VST-50F (6h)] were studied. C. albicans was chosen as a model organism for this study. The specimens were randomly divided into two subgroups and incubated in either 1.5 ml simulated saliva or nasal secretion containing C. albicans (ATCC 60193, set to 0.5 OD, 540 nm in advance) for 2h. Candida assays and adherence assays were made by inoculating C. albicans into Mueller Hinton Broth, Fluka added 500 mmol sucrose overnight. After fixation, specimens were stained by using sterilised Methylene Blue stain (Merck) and evaluated under optical microscope and SEM. For each material, on each specimen 15 different areas (mm(2)) were counted. Data were analysed using one-way ANOVA, paired sample t-test and Tukeys HSD (alpha=0.05). RESULTS Material type (p<0.05) and exposure media (p<0.05) showed a significant influence on the C. albicans adherence. VST-30 material showed the most C. albicans adherence in both saliva and nasal secretion (mean rank: 99.84 and 53.47, respectively) (p<0.05) and VST-50 had the least colonisation in both media (10.35 and 5.57, respectively). Microscopic evaluation showed clusters of blastospore cells of C. albicans being more spread out on VST-30 whereas cells were more localised on VST-50 and VST-50F. SIGNIFICANCE Among the tested materials, 12h room-temperature polymerised silicone elastomer resulted in less C. albicans adherence in both artificial saliva and nasal secretion.

Antimicrobial activity of volatile component and various extracts ofEnteromorpha linza (Linnaeus) J. Agardh from the coast of Izmir, Turkey

The methanol, dichloromethane, hexane, chloroform and volatile components ofEnteromorpha linza were testedin vitro for their antimicrobial activity against five Gram-positive, four Gram-negative bacteria andCandida albicans ATCC 10239. GC-MS analysis of the volatile components ofE. linza resulted in the identification of 35 compounds which constituted 84.76% of the total compounds. The volatile components ofE. linza consisted of n-tetratriacontane (8.45%), 1-heptadecanamine (6.65%) and docosane (6.46%) as major components. The methanol and chloroform extracts showed more potent antimicrobial activity than hexane and dichloromethane extracts. The volatile oils of these algae did not remarkably inhibit the growth of tested microorganisms.

Production of laccase from Trametes trogii TEM H2: a newly isolated white‐rot fungus by air sampling

This work represents the first report of isolation of potential laccase producers by air sampling using media supplemented with 2,2‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate) and guaiacol for laccase production and secretion indicators. Nine fungal isolates showed positive reactions with 2,2‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate) and guaiacol. The isolate named TEM H2 exhibited the largest and intensive oxidation zones with 2,2‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate) (85 mm) and guaiacol (66 mm) and therefore it was selected for detailed investigations. The strain was identified as Trametes trogii TEM H2 due to the morphological characteristics and the comparison of internal transcribed spacer ribosomal DNA gene sequences. The laccase production was screened in different liquid cultures. The best laccase production medium was determined as soluble starch yeast extract medium in which laccase production was reached to a maximum level (989.6 U l–1) on the 8th day of cultivation. Effects of different initial pH values on laccase production were tested. Optimum pH value for laccase production in soluble starch yeast extract medium was determined as pH 3.0 with 15425.0 U l–1laccase production at 12th day of cultivation. In addition, effects of eight inducers (veratryl alcohol, ferulic acid, 1‐Hydroxybenzotriazole, syringic acid, 2,2‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate), 1 mmol l–1 CuSO4, 3% ethanol, guaiacol) were examined. Only cultures with 2,5‐xylidine exhibited 1.9 fold increase in laccase activity reaching to 28890.0 U l–1. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)