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    Cyanobacterial Communities in Mucilage Collected from Çanakkale Strait (Dardanelles): Metagenomic Approach
    (Çanakkale Onsekiz Mart Üniversitesi, 2022) Yılmaz, Sevdan; Çelik, Ekrem Şanver; Yılmaz, Dilek Kahraman; Küçüker, Mehmet Ali
    In this study, cyanobacterial communities in mucilage samples collected from three stations in the Dardanelles Strait were analyzed with a metagenomic approach. Mucilage samples were collected at the beginning of June 2021 from three points of the Dardanelles (Station 1: 40°6'42.78"N, 26°23'57.00"E; Station 2: 40°9'8.09"N, 26°24'16.19"E; Station 3: 40°6 '21.62"N, 26°22'41.25"E). The dominant cyanobacteria were Prochlorococcus marinus (39.17%), Synechococcus sp. (20.85%), Lyngbya sp. (12.00%), Trichodesmium erythraeum (7.33%), Aphanocapsa sp. (4.33%) and Leptolyngbya sp. (3.33%), which constituted 87.00 % of the total number of sequences. In this study, cyanobacteria species that can cause harmful algal blooms and have toxic effects on the mucilage structure have been determined. The Marmara Sea and the Dardanelles Strait, which have been affected by serious disturbances, including industrial activities, anthropogenic impacts, tourism and artificial lighting, will never be fully restored to their former ecological state. In addition, cyanobacteria species in the mucilage may cause harmful algal blooms and have toxic effects that threaten the future well-being of coastal populations and ecosystem stability. Thus, the government and local authorities should pay more attention to combating the mucilage.
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    Fabrication of superhydrophilic TEOS-lactic acid composite films and investigation of biofouling behaviour
    (Kare Publishing, 2022) Ervan, Tuğçe; Küçüker, Mehmet Ali; Cengiz, Uğur
    Phytoplankton and diatom microalgae species cause biofouling by adhering to the surfaces, especially in closed cultivation systems such as tubular photobioreactors. This biofilm formation blocks the sunlight; after harvesting, it is necessary to clean the reactor. This cleaning process causes loss not only in time and finance but also in terms of environmental pollution due to using toxic chemicals and excess water usage. This study aimed to investigate the reduction of the microorganism cell adhesion on the hybrid surface. To succeed in this, the composite surface of tetraethoxysilane (TEOS) and lactic acid (LA) was prepared by the sol-gel process. Then the hybrid surfaces were coated on glass slides by the dip coating method. The wettability performance of the TEOS-LA hybrid surface was investigated using contact angle measurement and light transmittance. The wettability result showed that the super hydrophilic surface having 54 mJ/m2 of surface free energy values was obtained. Furthermore, the increased lactic acid content of the composite films increased the surface free energy (SFE) values, decreasing the water contact angle. A pencil hardness test characterized the mechanical strength of the surfaces, and it was determined that the hardness of the composite films was decreased by increasing the LA content of the composite films. Resultantly, it is found that the TEOS-LA superhydrophilic composite film reduces the adhesion of microalgae. © 2022, Kare Publishing. All rights reserved.
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    Hydrometallurgical recovery of neodymium from spent hard disk magnets: A life cycle perspective
    (Elsevier Ltd, 2021) Karal, Engin; Küçüker, Mehmet Ali; Demirel, Burak; Copty, Nadim K.; Kuchta, Kerstin
    Rare earth elements (REEs) are commercially used in an increasing number of critical or widely popular consumer and industrial products. Neodymium (Nd) element has emerged in recent years as one of the most critical REE, due to risks associated with its security of supply at required amounts. It has been widely reported that end of life (EoL) consumer electrical products contain significant amounts of metals and plastics. Thus, recovery of Nd from magnet scraps, EoL appliances or industrial applications is gaining even more strategic importance nowadays. In this study, an ex-ante life cycle assessment (LCA) of the hydrometallurgical recovery of Nd from waste electric and electronic equipment (WEEE) was conducted. The hydrometallurgical Nd recovery route consists of pretreatment, chemical leaching and Nd metal precipitation The feasibility and environmental performance of Nd metal recycling experiment model was investigated with an LCA scenario focusing on neodymium-iron-boron (Nd-Fe-B) magnet production. The LCA results were compared to that due to Nd-Fe-B magnet production from bastnäsite/monazite mineral ores using the traditional sintered magnet route. LCA sensitivity analysis and cost analysis were also performed. It was found out that, from both an economical and environmental point of view, magnet production from recovered Nd performed better than that of virgin magnet production. The scaled-up Nd metal recovery system reduced environmental impacts of Nd-Fe-B magnet production system by up to 65% for eight of the eleven environmental impact categories. Nd recycling reduced production cost from 8.55 to 3.98 USD/kg.
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    Metagenomic characterization of planktonic communities during a mucilage event in the Çanakkale Strait (Dardanelles), Turkey
    (2021) Yılmaz, Sevdan; Küçüker, Mehmet Ali; Kahraman, Dilek
    The present study investigates the planktonic communities through metagenomics sequencingduring a mucilage event in the Çanakkale Strait (Dardanelles), Turkey. Mucilage samples were collected inMay 2021 during an intense period of mucilage formation in three different stations of Dardanelles (Station1: 40°9'8.09\"N, 26°24'16.19\"E; Station 2: 40°6'21.62\"N, 26°22'41.25\"E; Station 3: 40°6'42.78\"N,26°23'57.00\"E). The dominant planktonic eukaryotes, at the phylum level, were Dinoflagellata (38.57%),Protalveolata (15.03%), Diatomea (12.41%), Nematozoa (8.44%), Apicomplexa (6.79%) and Chlorophyta(5.43%), which constituted 86.68 % of the total number of sequences. The most dominant OTUs (>10%),were Alexandrium and Syndiniales Group II. other dominant OTUs (>2%) were Viscosia sp., Lankesteria,Arcocellulus, Thalassiosira and Nannochloris. This study has clarified the situation of planktoniccommunities during a mucilage event in the Çanakkale Strait (Dardanelles), Turkey. As a result, the mostdominant genus was Alexandrium, which has been known to produce mucilage. Some Alexandrium speciescan produce toxins, cause severe impacts on human health, and lead to bivalve, shrimp, and fish mortality.Therefore, a more detailed study is needed to determine the Alexandrium toxins in the mucilage structure. Inaddition, the heavy metal content of the obtained mucilage was investigated, and the concentrations of the Asand Cr are above the disposal limits in the landfill sites. Therefore, collected mucilage from the sea surfaceshould be checked before sending it to landfill sites in terms of the heavy metal content.
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    Microalgal potential for nutrient-energy-wastewater nexus: Innovations, current trends and future directions
    (SAGE Publications, 2021) Panda, Sandeep; Mishra, Srabani; Akçıl, Ata; Küçüker, Mehmet Ali
    Agricultural, domestic and industrial activities contribute in releasing several organic and inorganic substances into the water streams that result in environmental pollution. Biological treatment of industrial and domestic wastewater using Activated Sludge Nutrient Removal (ASNR), the conventional process, is well known; however, it is relatively expensive due to the requirement for high energy inputs. Microalgal applications have been gaining interest as they offer potential cost-effective measures for the treatment of wastewater in the peri-urban and rural areas. Such systems provide an interesting tertiary biological treatment method where valuable biomass is produced with simultaneous uptake of nutrients such as nitrogen and phosphorous with reduction in coliform bacteria, heavy metals, chemical and biochemical oxygen demand (COD & BOD) and the removal/degradation of xenobiotic compounds etc. This paper provides a systematic review on the current microalgal applications (phycoremediation) for wastewater treatment with advanced information on their role towards nutrient recovery and energy (biogas) production under the third generation biorefinery concept. The use of advanced algal pond systems for wastewater treatment including pollutant degradation, microalgal cultivation and employing such facilities for biogas production in view of technology applications is emphasized. This inter-linked network indicating microalgal role into the Nutrient-Energy-Wastewater nexus with future directions and concluding remarks are discussed.
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    Mikroyosun Üretiminde Biyolojik Olarak Kirlenmeyen Akıllı Fotobiyoreaktör Üretimi
    (2023) Cengiz, Uğur; Haznedaroğlu, Berat Zeki; Küçüker, Mehmet Ali; İpsalalı, Özde; Belen, Sema Nur; Durmaz, Fatma Gülçin; Güneş, Kaniye
    Dünyamızda son zamanlarda karşılaşılan doğa olayları, iklim değişiklikleri ve bunlara ek olarak son pandemi süreci insanoğluna sürdürülebilir gıdanın önemi ve gerekliliğini net bir şekilde hatırlatmıştır. Bu yüzden alternatif sürdürülebilir gıda kaynaklarına olan arayış son zamanlarda bilim insanlarının ilgi odağı haline gelmiştir. Yosunlar gün ışığı altında fotosentez yaparak açık ve kapalı sistemlerde üretilebilir. Gıda ve ilaç gibi saf ürünlerin üretilmesinde tür çeşitliğinin kontrolü açısından kapalı sistemlere ihtiyaç vardır. Ancak, kapalı sistemlerde mikroyosunların büyümesi sırasında reaktör yüzeyine yapışıp biyofilm oluşturma gibi bir dezavantajı vardır. Biyofilm oluşumu da güneş ışınının reaktör içerisine girmesini engeller. Ayrıca, biyofilm varlığı hasat sonrası reaktörün bazı kimyasallar ile temizlenmesi gerekliliğini ortaya çıkarmaktadır. Reaktörün temizliği hem zaman hem de maddi kayıpla birlikte temizlik esnasında kullanılan kimyasalların ve fazla su tüketimi yüzünden çevre kirliliğine neden olmaktadır. Bu problem, mikroyosun üretiminde kullanılan reaktör yüzeyinin modifiye edilerek, üretim sırasında yosunların bu yüzeye yapışması engellenerek çözülebilir. Bu projede yapısında OH grupları olan yüksek yüzey enerjili monomerler ve polimerlerden oluşan yeni Ormosil kaplamalar üretilmiştir. Bu kaplamalar daldırma tekniği ile mikroskop camı yüzeyi kaplayıp açık havada hidrofilik, su altında süperoleofobik yüzeyler üretilmiştir. Mekanik ve kimyasal testlerden geçen yüzeyler, biyopolimer içeriği fazla, tatlı su mikroyosunları olan Chlorella vulgaris, Chlorella sorokiniana, Ettlia oleoabundans ve deniz suyu türü olan Nannochloropsis sp ile adezyon testine tabi tutulmuştur. Bu test yüzeyin hasat süresince mikroyosun içerisinde bekletilip her geçen gün yüzeyde oluşan biyofilm miktarının ölçülmesi ile yapılacaktır. Yapılan deneysel ve model sonuçları karşılaştırılarak mikroyosun yapışmasını engelleyen en iyi yüzey sentezi sonucunda proje nihai hedefi olan ?mikroyosunlara karşı biyolojik olarak kirlenmeyen ve hasat sonrası temizlenme ihtiyacı duyulmayan akıllı reaktör tasarımı? için fotobiyotakörler özel bir düzenekte daldırma tekniğinin tersi bir şekilde kaplanmıştır. Daha sonra kaplanmış ve kaplanmamış PBR içerisinde seri mikroyosun üretimi yapılmıştır. Yapılan çalışmalar sonunda en fazla protein içeriği olan Chlorella vulgaris? in seri üretiminde modifiye fotobiyoreaktörün kaplanmamışa göre % 50 daha az kirlendiği bulunmuştur. Proje Çanakkale Onsekiz Mart Üniversitesinde yürütülmüştür. Proje danışmanı Boğaziçi Üniversitesi, Çevre Bilimleri Enstitüsü öğretim üyesi ve aynı zamanda İstanbul Mikroyosun Biyoteknolojileri Araştırma ve Geliştirme Birimi Müdürü Dr. Öğr. Üyesi Berat Z. Haznedaroğlu?dur. Kendisi kullanılması planlanan mikroyosun türleri için saf türün sağlanmasında ve tecrübe aktarımında proje ekibine destek olmuştur. Proje araştırmacısı Dr. Öğr. Üyesi Mehmet Ali Küçüker, uzmanlık alanı mikroyosun üretimi ve teknolojileri üzerinedir. Kendisi cam kaplamaların ve sonrasında fotobiyoreaktörlerin mikroyosun türlerine karşı yapışma testlerini yapmıştır. Proje yürütücüsü polimer sentezi ve uygulamaları ile polimerik yüzeylerin ıslanabilirlik davranışları üzerine uzmandır. Kendisi tüm kaplama çözeltilerinin üretilmesinde ve kaplamların yapılmasında, ıslanabilirlik testleri ile mekanik ve kimyasal datanım testlerin yapılmasından sorumludur. Önerilen bu projede bir lisans (star bursiyer) bir yüksek lisans (Ocak ayında mezun olacak) ve iki de doktora öğrencisi (biri biyolojik kirlenme üzerinde diğeri polimer sentezi ve karakterizasyonu üzerinde) çalışmışlardır.
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    Shotgun Metagenomic Analysis for Mucilage in the Surface Waters of The Çanakkale Strait (Dardanelles): Metabolic Diversity, Microbial Community Structure and Antibiotic Resistance Genes
    (2021) Yılmaz, Sevdan; Kahraman, Dilek; Çelik, Ekrem Şanver; Küçüker, Mehmet Ali
    In this study, we used shotgun metagenome sequencing to examine the metabolic diversity, microbial community structure and diverse antimicrobial resistance genes of mucilage in the surface waters of the Çanakkale Strait (Dardanelles). Mucilage samples were collected in April 2021 from the three different stations of the Dardanelles. The dominant microbial communities at the phylum level were Bacteroidetes (20.06%), Proteobacteria (13.68%), Verrucomicrobia (6.25%), Planctomycetes (3.02%) and Cyanobacteria (2.5%). Metabolic pathway analysis using KEGG (Kyoto Encyclopedia of Genes and Genomes) revealed that most of the genes of mucilage samples were involved in unclassified (73.86%) followed by metabolism (14.45%), genetic information processing (4.16%), environmental information processing (2.57%), cellular processing (1.88%), human diseases (1.61%), and organismal systems (1.47%). The dfrA3 gene was the most prevalent (20.36%) followed by CRP (18.17%), PmrE (14.92%), rpoB2 (11.17%), SoxR (7.49%), AbeS (6.83%), baeR (5.22%), PmrF (3.70%), dfrA22 (2.20%), dfrA26 (1.76%), dfrA20 (1.63%), golS (1.26%), CAT (1.03%), mtrA (1.01%), TMB-1 (0.64%), novA (0.64%), dfrK (0.59%), vanXB (0.48%), dfrG (0.39%), FosC2 (0.31%), and MexA (0.20%) genes. Antibiotic resistance gene (ARG) types mainly included the resistance genes of multidrug (40.19%), trimethoprim (26.93%), polymyxin (18.62%), rifamycin (11.17%), chloramphenicol (1.03%), aminocoumarin (0.64%), beta-lactamase (0.64%), fosfomycin (0.31%), and vancomycin (0.48%). Antibiotic-resistant bacteria in mucilage can adhere to human skin during swimming, fishing, water sports etc., enter the body through the nose and mouth, and transfer genetic information to the bacteria in contact areas in the human body. Therefore, this situation is risky in public health, and necessary precautions should be taken. In the light of these findings, it has been observed that there is a need for more detailed studies in the future.