Determination Of The Synergistic Acute Effects Of Antibiotics On Methanogenic Pathway

Tez (Yüksek Lisans) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2012Thesis (M.Sc.) -- İstanbul Technical University, Institute of Science and Technology, 2012Bu çalışmada, seçilmiş antibiyotik karışımlarının havasız koşullarda mikrobiyal komünitenin metanojenik aktivitesi üzerindeki kısa süreli inhibisyon etkisi incelenmiştir. Bu kapsamda, üç değişkenli akut testler tasarlanmıştır. Birinci değişken substrat çözeltisinin içeriğidir (asetat, bütirat ve uçucu yağ asidi karışımı). Diğer değişken antibiyotik karışımının kompozisyonudur (Sulfametoksazol, Eritromisin ve Tetrasiklin). Son değişken ise antibiyotik konsantrasyonudur (1 – 250 mg/L). Yapılan istatistiksel analizler antibiyotik karışımının konsantrasyonu ile toplam metan üretimi arasında anlamlı bir ilişki olduğunu göstermektedir. Tüm substrat koşullarında, en yüksek inhibisyon etkisini 250 mg/L Sulfametoksazol ve Tetrasiklin karışımı içeren test şişeleri göstermiştir. Test şişelerinin tamamında, antibiyotik karışımlarının kısa süreli inhibitör etkisi 100 mg/L konsantrasyondan sonra gözlenmiştir. Test sonuçları antibiyotik karışımlarının asetoklastik metanojenlerin toplam metan üretimi üzerindeki inhibisyon etkisinin, karışımı oluşturan antibiyotiklerin her birinin oluşturduğu etkiden daha fazla olduğunu göstermiştir.In this study, the mixture short-term effects of selected antibiotics on methanogenic activity of a microbial community under anaerobic conditions were determined. In this scope, acute tests were designed based on a three-way factorial design where one factor was the composition of the substrate solution (acetate, butyrate, and VFA mixture), another factor was the composition of antibiotic mixtures (Sulfamethoxazole, Erythromycin, and Tetracycline) and the last factor was concentration of antibiotics added (1 – 250 mg/L). Statistical analyses showed that, there is a strong correlation between antibiotic mixture concentration and methane generation. For all substrate conditions, 250 mg/L ST mixture had the highest inhibitory effect on total methane production. After 100 mg/L, short-term inhibitory effect of antibiotic mixtures was seen clearly in all test bottles. The results showed that, mixtures had higher inhibition effect on total methane production of acetoclastic methanogens than single compounds.Yüksek LisansM.Sc

Waste to energy: valorization of spent tea waste by anaerobic digestion

The conversion of renewable resources into value-added products such as bioenergy is one of the growing concerns of bioeconomy strategy. Within this concept, assessing the proper combination of local wastes has major importance. This study set out to assess the feasibility of using spent tea waste as a single and co-substrate on anaerobic digestion and to explore the influence of the amount of microorganisms on the digester performance. For this purpose, biomethane potentials tests were conducted for seven different mixing ratios of spent tea waste and cow manure on a mass basis. The reactors operated under mesophilic conditions for 20 days with two inoculum/substrate ratios. The results revealed that using spent tea waste as a co-substrate did not reveal a significant effect on biomethane production in the reactors. Contrarily, the amount of inoculum had a remarkable effect on biomethane production, resulted in an increase in methane production between 28 and 32%. While the biomethane yields were in the range of 129-138 mL(N)CH(4)g(VS)(-1)for the co-digesters operated with inoculum/substrate ratio of 1, the range was 165-181 mL(N)CH(4)g(VS)(-1)for the co-digesters operated with inoculum/substrate ratio of 2. These findings represent the potential usage of the spent tea waste as a co-substrate within the sustainable waste management approach and are relevant to plant operators

Bioenergy generation from spent tea and potato wastes through anaerobic codigestion within bioeconomy approach

INTRODUCTION Anaerobic digestion is a well-established process in which renewable energy carrier-biogas is simultaneously generated through upcycling of organic waste streams. Biogas is a green energy vector having a crucial role in the future sustainable bioeconomy development. Flexibility of these systems such as digestion of multiple feedstock enables not only energy production but also waste management and has an economic potential for the locals. The combination of the local wastes has a great concern within this perspective. Potato production is one of the major agricultural activities in worldwide including Turkey and nearly 100 ktons/year of peels are produced from potato industry globally. Turkey is one of the important tea producers worldwide, the production is over 225 thousand tons/year. Since tea is a popular beverage, spent tea waste amount is considerable potential in the country. The aim of this study was to optimize the inoculum amount in the anaerobic digesters treating spent tea and potato waste.MATERIALS&METHODS Within this scope, biomethane potential tests were set up for five different inoculum/substrate ratios (I/S: AD1:1.0, AD2:1.5, AD3:2.0, AD4:2.5, AD5:3.0) on the basis of volatile solids (VS). Anaerobic batch tests were conducted by Automatic Methane Potential Test System (AMPTS) II (Bioprocess Control, Sweden), active reactor volume was 400 mL. The reactors were operated in triplicates under mesophilic conditions for 20 days. The blank reactors including only standard inoculum without feedstock were also conducted and the background biomethane production was subtracted from the experimental setups. The results were reported based on the VS content of the feedstock in the reactors.RESULTS The results showed a clear effect of I/S ratio in biomethane production (Figure 1). Whereas increasing I/S ratio resulted faster biogas production in the system, the highest methane yield was recorded as 244 mLN CH4 gVS-1 in AD4 operated with I/S of 2.5. The methane yields were gradually increased with increasing I/S ratio and ranged between 225-244 mLN CH4 gVS-1 except AD5 in which the methane yield was 233 mLN CH4 gVS-1. There was not a significant difference on VS values between the reactors s at the end of the operation period (%1.9 ± 0.01). Soluble COD values were in the range of 2180 mg/L - 410mg/L. Alkalinity was measured as 4250 ± 45 mg/L showing there was not a limitation in the reactors regarding buffering acidity. I/S ratio is a key parameter affecting VFA production and methane generation rates. Since increasing amount of inoculum enables higher biomethane yield, while shortening the incubation period, it should be noted that, the optimum value for I/S ratio is highly dependent on substrate characterization and inoculum source.CONCLUSION In the sustainable circular economy approach, bioenergy has a major role in green energy production and optimization of optimization of the operating conditions for local feedstock has a crucial role. Results revealed that, the spent tea waste and potato waste are potential feedstock in anaerobic digesters whereasthe optimum I/S ratio is 2.5. These findings offer practical information to future applications of biomethane production with spent tea and potato waste as feedstock.Keywords: anaerobic co-digestion, bioeconomy, biomethane potential, tea waste, potato wast

Comparative Assessment of Biogas Production Potential of the Most Abundant Agro-residues in Turkey

Recent energy policies promote energy generations from green resources to meet sustainability criteria. Since Turkey is one of the largest agricultural producers globally, it has great biogas production potential. This study aims to evaluate the biomethane yields of the most abundant agro-residues in Turkey and to assess their potentials for contribution to biogas production. Within this scope, sunflower heads, tea residues, cotton stalks, and crop residues; wheat, rye, and triticale straws were collected from different regions of Turkey. Anaerobic batch digesters were conducted to investigate the biomethane production of the selected feedstock and operated for 30 days at 37°C. Each setup was conducted in triplicates and methane productions were monitored online. The main methane production route of the inoculum was determined as acetoclastic methanogenesis while Cloacimonetes, Firmicutes, and Bacteroidetes composed the core bacterial phyla. The greatest methane yield was observed in the digesters operated with the wheat straw followed (164 NmL/gVSinfluent) by triticale straw and sunflower head. The lowest yields were calculated for the digesters fed with the cotton stalks (71 NmL/gVSinfluent). To increase the biomethane potential yields in the anaerobic digesters operated with agro-residues and to make the anaerobic digesters more feasible, operational conditions should be optimized and physico-chemical and biological pre-treatment techniques and/or bioaugmentation applications should be integrated into the systems

Comparative study of benthic diatom community using 18S rDNA metabarcoding and light microscopy in the Bosphorus, Turkey

Diatoms are one of the major algal groups having an important role in the aquatic systems in which they constitute the main primary production with dinoflagellates in the coastal regions, and can contribute to photosynthesis at great rates. There had been intense effort to reveal diatom community with light microscopy (LM) and scanning electron microscopy (SEM), on the other hand, DNA barcoding techniques had been an interest to understand the microbiome in the last decades. Barcoding provided rapid response on the targeted organisms and introduced many new species. Recently, monocultural molecular studies showed that species could be described with accurate and reliable results. DNA metabarcoding approaches yielded to determine the whole organisms with available DNA data in the sample and major advances on next-generation sequencing platforms enable to widen the application of metabarcoding approach to various environmental samples.The aim of this study was to perform a comparative assessment of the diatom community structures in Bosphorus of Istanbul, Turkey by LM and 18S rDNA metabarcoding. Diatom samples were collected by brushing from the submerged stones of 10 cm2 of area taken from the coast of Beykoz on the Asian part of the Bosphorus, Istanbul and processed for LM and metabarcoding in June 2020. To concentrate the sample, the scrapes of the biofilm filtered from a 0.22-micron filter, and eDNA was extracted from that filter paper using MN NucleoSpin Soil DNA isolation kit (Macherey-Nagel, Germany) following the manufacturer's protocol and diatom community profile was analyzed by targeting the V4 region of the 18S rRNA gene using Illumina® MiSeq™.DNA metabarcoding results revealed two classes Bacillariophyceae (91%) and Mediophyceae (9%) (Fig. 1). While small-celled Hyalosira delicatula Kützing was the most abundant taxa with 40% abundance and it was followed by Licmophora spp. (33%). 28% of Licmophora sequences could not be assigned to any species and remained as unidentified, Licmophora gracilis (Ehrenberg) Grunow (4%), and L. flabellata (0.9%) detected at lower abundances. Besides, one of the common genera of diatoms, Navicula spp., showed a relative abundance of 4% and another common genus Nitzschia spp. were represented only by N. commutata Grunow and composed 0.5% of the community.While 18S rDNA metabarcoding revealed 11 genera, LM investigation identified 17 genera belonging to 21 species. 4 genera were common in both techniques and Licmophora flabellata was detected in both LM and metabarcoding methods. Interestingly, small celled taxa which could be easily overlooked in LM was detected with 18S metabarcoding. The results presented a promising number of genera which could be detected by both methods (Fig. 2).DNA metabarcoding of diatoms is a new area of research in the coastal waters and there are few studies performed so far and this is the first study relying on the rDNA metabarcoding of diatoms in the aquatic systems in Turkey. The comparison of the taxa using microscopy methods and metabarcoding techniques indicated some significant differences in the diatom composition. However, the results here with 18 species with metabarcoding vice-versa 21 taxa with microscopy methods confirms poor biodiversity in the Bosphorus. However, this study based on one sampling effort in one station for the comparison of the two methods, we had LM results from more stations in different seasons supporting the lower biodiversity. eDNA data is scarce from the coastal areas and our results comprise a promising number of genera. Results of this study could provide data for further research, which high number of diatoms could be determined with eDNA metabarcoding

Assessment of microbial community diversity in lakes of İğneada floodplain forest by metabarcoding approach

This paper aims to contribute to the understanding of bacterial community patterns of the lakes of İğneada Floodplain Forest by metabarcoding approach. Within this scope, surface water samples were collected from three lakes located in the area namely Mert Lake, Hamam Lake, and Saka Lake, and the bacterial diversity was assessed by a high throughput sequencing of the 16S rRNA gene. Chao1 richness and Shannon diversity were higher in Saka Lake indicated a more diverse bacterial community. Proteobacteria was by far the most abundant phyla in all lakes. Although Bacteroidetes and Actinobacteria also dominated the community, their abundances differed in each lake. While the family Burkholderiaceae represented 25% of the bacterial community in Saka Lake, the abundances were 9% and 4% in Hamam Lake and Mert Lake, respectively. This study is one of the first investigations specifically focused on the bacterial communities in three lakes of İğneada Floodplain by next-generation sequencing platform and gave a prescreening of the bacterial diversity. Further studies are required to determine the biotechnological potential of this unique habitat

Pachnoda Marginata Larva'sının arka bağırsağından anaerobik lignoselülitik mikrobiyal kültür geliştirilmesi

Tarım atıkları, yüksek enerji içerikleri ve üretim miktarları ile düşük maliyetleri nedeniyle anaerobik çürütücüler için en önemli biyokütle olarak değerlendirilmesine rağmen karmaşık lignoselülozik yapıları bu maddelerin hidroliz aşamalarını sınırlandırmaktadır. Hidroliz verimini artırmak için etkin lignoselüloz degradasyon stratejileri geliştirilmektedir. Bu çalışmanın amacı, Pachnoda marginata larvalarının arka bağırsağından lignoselüloz parçalayabilen anaerobik mikrobiyal topluluğun zenginleştirilmesidir. Bu kapsamda, Pachnoda marginata larvaları 3 hafta süre ile lignoselülozik substrat ile beslenmiş, sonrasında disekte edilmiştir. Arka bağırsak kültür şişelerine transfer edilmiştir. Bakteriyel topluluk çeşitliliği 16S rRNA amplikon dizileme yöntemi ile Illumina MiSeq platformunda analiz edilmiş, metanojenik arkeal topluluk ise T-RFLP yöntemi ile incelenmiştir. Kültür şişelerinde biyogaz üretimi zaman ile artış göstermiş, tüm şişelerde metan üretimi gözlenmiştir. Zenginleştirme prosedürü sonucunda, kültürün bakteriyel topluluk profili değişiklik göstermiş, üç transfer sonrasında alınan örneklerde Porphyromonadaceae (phylum: Bacteroidetes) bolluğunun artarak baskıladığı görülmüştür. Metanojenik topluluk ise Methanobrevibacter ile baskılanmıştır. Çalışmada elde edilen sonuçlar, Pachnoda marginata larvasının sindirim sisteminden üretilen zenginleştirilmiş kültürün, lignoselülozca zengin kompleks biyokütleyi etkin bir şekide parçalayabildiğini göstermiştir