Remediation of anionic surfactants and ammonium by biological materials

Ankara : The Materials Science and Nanotechnology Program of the Graduate School of Engineering and Science of Bilkent University, 2012.Thesis (Master's) -- Bilkent University, 2012.Includes bibliographical references leaves 83-97.Surfactants are the main components in detergents and they are primarily discharged from household and industry. Ammonia (or ionized form ammonium) is a byproduct of animal and human metabolism and it is formed in and discharged from aquaculture. Contamination of soil and water sources by surfactants and ammonium is becoming a big problem because of their harmful effects. These substances are highly toxic to many organisms, leading to possible mass deaths in the freshwater ecosystem. As their presence causes a potential environmental risk, industrial and household wastewater systems should be adequately treated to reduce the concentration of ammonium and surfactants. Chemical and biological methods are primarily used to treat wastewater systems. Biological treatment methods are more eco-friendly in comparison to chemical methods. Among biological treatment methods, the use of specific bacteria strains for removal of chemical contaminants is a widely applied process for treatment of industrial and municipal wastewater. However, those bacteria may not be capable of withstanding harsh environmental conditions or they may not specifically degrade the contaminant of interest, so isolation of bacterial strains more resistant to environmental extremes and more suitable for bioremoval is a possible strategy to improve current wastewater treatment strategies. By isolating bacteria well-adapted to the environmental and physical conditions of the system to be cleaned, very high efficiencies can be obtained for wastewater cleaning. To this end, a two-step approach was used. In the first part of this project, our aim was to find an integrated efficient biological based method to clean up industrial wastewater from anionic surfactants. Two main strategies were utilized to solve this problem: Finding and applying a more biodegradable and eco-friendly detergent alternative, and developing a biological treatment method specific for the anionic surfactants in the wastewater system of interest. It is expected that, by combining these two strategies, anionic surfactants in wastewater can be removed more efficiently. In the second part of this project, a novel bacterial strain, which we termed STB1, was isolated from a commercial sea bass farm and found to display high heterotrophic ammonium removal characteristics. The species identity of STB1 was determined to be Acinetobacter calcoaceticus. We evaluated ammonium removal characteristics of STB1 at varying ammonium concentrations, and observed that STB1 can almost completely remove ammonium at low (50 mg/l) and medium (100 mg/l) concentrations within 72 h, while 45% ammonium removal was observed at a higher concentration (210 mg/l) during the same time period. Trace amounts of metabolized ammonium was converted to nitrite or nitrate and 22.16% of ammonium was introduced to cell biomass, while 4.34% of total nitrogen was initially incorporated into biomass and subsequently released to the supernatant fraction in the 100 mg/l sample. Most of the remaining conversion products are expected to be gaseous denitrification products. Toxicological studies with Artemia salina (brine shrimp) nauplii revealed that STB1 strain is non-toxic to Artemia larvae, which suggests that STB1 can be safely and efficiently utilized for water quality enrichment in aquatic ecosystems.Sarıoğlu, Ömer FarukM.S

Elektrospin yöntemi ile üretilmiş nanolif yapılara biyolojik malzemelerin entegre edilerek çevresel uygulamalar için kullanılması

Cataloged from PDF version of article.Thesis (Ph.D.): Bilkent University, Department of Materials Science and Nanotechnology, İhsan Doğramacı Bilkent University, 2016.Includes bibliographical references (leaves 157-165).Electrospinning is an easy and economical production technique to produce nanofiber/nanofibrous webs from different polymers, polymer mixtures, inorganic materials, supramolecular structures and composite materials. These nanofibers have unique physical/chemical properties due to their large surface areas and highly nanoporous structures. Since these nanofibers have superior properties, various functions and can be modified by physical/chemical methods, they have a great potential to be applied in membrane/filter applications. Bioremediation is a commonly used technique for removal of water contaminants, and different kinds of bacteria have been used for bioremediation of water systems. Use of biointegrated hybrid materials is an alternative approach for bioremediation, and this may provide higher efficiency, ease of application and reusability. As a carrier system, electrospun nanofibers are suitable materials for integration of bacteria, since electrospinning can allow production of nano/micro scale composites with tunable physical/chemical properties. In this thesis, it was aimed to integrate bacteria that have bioremediation capability with electrospun nanofibers by using immobilization/encapsulation techniques and test the potential of these biocomposites for treatment of contaminated water systems. The integration of bacteria that can remediate ammonium, heavy metal, textile dye and surfactant with electrospun nanofibers was achieved by two different approaches. In the first approach, bacterial cells were physically immobilized on cellulose acetate (CA), polysulfone (PSU), polystyrene (PS), polycaprolactone (PCL) and polylactic acid (PLA) electrospun nanofibers. In order to observe effects of nanofiber/nanofibrous web morphology and arrangements on the immobilization of bacteria, some of these nanofibers were produced as porous, parallelly arranged, and with different diameters. In the second approach, by using polyvinyl alcohol (PVA) and polyethylene oxide (PEO) polymers, simultaneous encapsulation of bacteria in nanofiber structures was provided. Afterwards, all these different kinds of biocomposites were tested for their remediation potential in accordance with the intended use of the integrated bacteria.by Ömer Faruk Sarıoğlu.Ph.D

Fourier transform infrared spectroscopy as a novel approach for analyzing the biochemical effects of anionic surfactants on a surfactant-degrading arcobacter butzleri strain

Anionic surfactant-biodegrading capability of an Arcobacter butzleri strain was analyzed under aerobic conditions. The A. butzleri isolate displayed efficient surfactant-biodegrading capacity for sodium dodecyl sulfate (SDS) at concentrations of up to 100 mg/L in 6 days, corresponding to 99.0% removal efficiency. Fourier transform infrared spectroscopy was applied to observe the effects of varying concentrations of SDS on the biochemistry of bacterial cells. Results suggest that protein secondary structures were altered in bacterial cells at sufficiently high SDS concentrations, concurrent with SDS biodegradation

Characteristics of pediatric multiple sclerosis: The Turkish pediatric multiple sclerosis database

Objective To document the clinical and paraclinical features of pediatric multiple sclerosis (MS) in Turkey. Methods Data of MS patients with onset before age 18 years (n = 193) were collected from 27 pediatric neurology centers throughout Turkey. Earlier-onset (<12 years) and later-onset (?12 years) groups were compared. Results There were 123 (63.7%) girls and 70 (36.3%) boys aged 4–17 years, median 14 years at disease onset. Family history of MS was 6.5%. The first presentation was polysymptomatic in 55.4% of patients, with brainstem syndromes (50.3%), sensory disturbances (44%), motor symptoms (33.2%), and optic neuritis (26.4%) as common initial manifestations. Nineteen children had facial paralysis and 10 had epileptic seizures at first attack; 21 (11%) were initially diagnosed with acute disseminated encephalomyelitis (ADEM). Oligoclonal bands were identified in 68% of patients. Magnetic resonance imaging revealed periventricular (96%), cortical/juxtacortical (64.2%), brainstem (63%), cerebellum (51.4%), and spinal cord (67%) involvement. Visual evoked potentials (VEP) were abnormal in 52%; serum 25-hydroxyvitamin D levels were low in 68.5% of patients. The earlier-onset group had a higher rate of infection/vaccination preceding initial attack, initial diagnosis of ADEM, longer interval between first 2 attacks, and more disability accumulating in the first 3 years of the disease. Conclusion Brainstem and cerebellum are common sites of clinical and radiological involvement in pediatric-onset MS. VEP abnormalities are frequent even in patients without history of optic neuropathy. Vitamin D status does not appear to affect the course in early disease. MS beginning before 12 years of age has certain characteristics in history and course