Plastic waste production around the world is increasing, which leads to global plastic waste pollution. The need for an innovative solution to reduce this pollution is inevitable. Increased recycling of plastic waste alone is not a comprehensive solution. Furthermore, decreasing fossil-based plastic usage is an important aspect of sustainability. As an alternative to fossil-based plastics in the market, bio-based plastics are gaining in popularity. According to the studies conducted, products with similar performance characteristics can be obtained using biological feedstocks instead of fossil-based sources. In particular, bioplastic production from microalgae is a new opportunity to be explored and further improved. The aim of this study is to determine the current state of bioplastic production technologies from microalgae species and reveal possible optimization opportunities in the process and application areas. Therefore, the species used as resources for bioplastic production, the microalgae cultivation methods and bioplastic material production methods from microalgae were summarized.

Waste mobile phones constitute one of the fastest growing Waste Electrical and Electronic Equipment (WEEE) types all over the world due to technological innovations and shortening of their life span. They contain a complex mix of various materials, such as basic metals, precious metals and rare earth elements and represent an important secondary raw metal source. The main objectives of this study were to characterize the metal concentration of waste mobile phones by optimizing the inductively coupled plasma optical emission spectrometer (ICP-OES) operation parameters and estimate the metal recovery potential of waste mobile phones in Turkey. Therefore, selected mobile phone samples collected from a recycling center in Turkey were analyzed to determine their metal concentrations. Then, the theoretical recovery potentials of precious and rare earth metals from waste mobile phones were estimated for Turkey. The analytical methods optimized in this study can help further research activities to obtain comprehensive data for determination of the critical metals (precious metals and rare earth elements) in WEEE samples so that proper recycling and recovery strategies can be selected and implemented.

Bu çalışma da Çanakkale Boğazı'ında (Dardanel) müsilaj oluşumu sırasında planktonik toplulukların kompozisyonları metagenomik yaklaşımla araştırılmıştır. Müsilaj örnekleri, Çanakkale Boğazı'nın üç farklı istasyonunda (İstasyon 1: 40°15'22.53"K, 26°40'43.58"D; İstasyon 2: 40°10'59.21"K 26°37'81.17"D; İstasyon 3: 40°11'15.67"K, 26°39'90.81"D) yoğun müsilaj oluşumu gözlemlenen Mayıs 2021'de toplanmıştır. Filum düzeyinde toplam sekans sayısının 86.68% ini kapsayan baskın planktonik ökaryotlar, Dinoflagellata (%38.57), Protalveolata (%15.03), Diatomea (%12.41), Nematozoa (%8.44), Apicomplexa (%6.79) ve Chlorophyta (%5.43) olarak belirlenmiştir. En baskın OTU'ler (>%10), Alexandrium ve Syndiniales_Group_II olup, diğer baskın OTU'lar (>%2) ise Viscosia sp., Lankesteria, Arcocellulus, Thalassiosira ve Nannochloris olmuştur. Bu çalışma, Türkiye'de meydana gelen bir müsilaj olayı sırasında Çanakkale Boğazı'nda planktonik toplulukların durumunu netleştirmiştir. Sonuç olarak, en baskın cinsin müsilaj üretme kabiliyeti olduğu bilinen Alexandrium olduğu belirlenmiştir. Bazı Alexandrium türleri toksin üretebilir, insan sağlığı üzerinde ciddi etkilere neden olabilir ve çift kabuklu, karides ve balık ölümlerine yol açabilir. Bu nedenle müsilaj yapısındaki Alexandrium toksinlerinin belirlenmesi için daha detaylı bir çalışmaya ihtiyaç vardır. Ayrıca elde edilen müsilajın ağır metal içeriği araştırılmıştır. Müsilajın yapısındaki As ve Cr konsantrasyonları atıklar için belirlenen düzenli depolama sahalarına bertaraf etme sınırlarının üzerindedir. Bu nedenle deniz yüzeyinden toplanan müsilajın düzenli depolama sahalarına gönderilmeden önce ağır metal içeriği kontrol edilmelidir.

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.

Asbestos is a general term employed for crystallized silicate minerals in fibril form. It can be commonly found in nature and from which fibre uses in the industry through processing are obtained. It is dielectric and fibrous, having an elastic feature. However, there is limited information about the air quality in terms of asbestos for the companies that produce refractory materials from magnesite ore. This deficiency in the literature can be eliminated with this study for a company with high quality and durable refractory materials. Among the most commonly used asbestos analysis are scanning electron microscope (SEM), transmission electron microscope (TEM). Asbestos analyses have been performed in two different institutions on the parallel samples whose preliminary processes have been completed. According to the results of the examinations conducted by SEM, 23 of the fibrils observed in a total area are bigger than five µmin lengths and less than 3 µm in width. Three of these fibrils were observed to have the characteristics of chrysotile fibres morphemically and elementally. In addition, airborne samples were analyzed using a TEM instrument. According to the results obtained, 13 of the fibrils observed in total were bigger than 5 µm in length and less than 3 µm in width and based on ED analysis and elemental composition (EDXA) results of these fibrils, and they were not observed to have the characteristics of chrysotile fibres. The majority of the fibrils observed were noted to be other inorganic minerals (lizardite) fibrils. Additionally, the obtained results show that the asbestos concentration in the air is below the limit specified by the provision (0,1 fiber/cm3).