Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
5 results
Search Results
Article Citation - WoS: 2Citation - Scopus: 1Dynamics of Co2 Consumption, and Biomass and Lipid Carbon Production During Photobioreactor Cultivation of the Diatom Cyclotella(TÜBİTAK - Türkiye Bilimsel ve Teknolojik Araştırma Kurumu, 2023) Ökten, HaticeUnderstanding of CO2 delivery and consumption dynamics in algal photobioreactors are critical to unravel microalgae’s full potential for bioproduct generation and carbon capture from flue gas streams. This study aims to expand our current understanding by cultivating the diatom Cyclotella under controlled process conditions of a bubble column photobioreactor and analyzing CO2 consumption dynamics in real time using results from an online CO2 sensor connected to the reactor exhaust. Two sets of experiments were conducted: they served to contrast the influence of silicon and nitrate (Si&N colimitation) and Si limitation, and the light availability, respectively. CO2 consumption was calculated based on the mass balance around the reactor inlet and outlet gas streams. Biomass samples and lipid extracts were analyzed for carbon (C) content to determine biomass-C and lipid-C concentrations. The outlet CO2 concentrations varied significantly with cultivation time and process conditions. More than 15% to 65% of the CO2 introduced left the reactor in the exhaust at any instance based on the set CO2 transfer rates. The highest average daily capturing efficiency was 60%. Nutrient limitation regimes imposed generated unique CO2 consumption profiles undiscernible by the biomass-C analysis, i.e. unlike Si limitation, N limitation had more immediate detrimental effects on C consumption. Final biomass-C concentration increased with increasing N and light availability, 275 mg/L vs. 336 mg/L, and 270 mg/L vs. 501 mg/L, respectively. Biomass-C based capturing efficiency approximations resulted in 20% to 40% underestimation. Under Si-limited conditions, the higher light intensity increased the final lipid-C to biomass-C ratio by two times (from 20% to 40%) and the final lipid-C concentration and peak productivity by four times (from 56 mg/L to 216 mg/L, from 7 to 30 mg/L-day, respectively). This study demonstrates online exhaust CO2 concentration-based analysis’s unique capabilities for assessing carbon availability and capture, organic-C production, and its diversion to biomass and lipid production.Article Citation - WoS: 2Citation - Scopus: 2Evaluating the Performance of Conventional Daf and Posidaf Processes for Cyanobacteria Separation at a Pilot Plant Scale(IWA Publishing, 2022) Yap, Russell K.L.; Rao, N. R.H.; Holmes, M.; Whittaker, Michael; Stuetz, Richard M.; Jefferson, Bruce; Bulmuş, Volga; Peirson, William Leslie; Henderson, R. K.In this work, a commercially available water treatment polymer poly(N,N-diallyl-N,N-dimethylammonium chloride) (PDADMAC) and a hydrophobically modified polymer (HMP) designed to adhere to bubble surfaces were applied for the first time in the novel Posi-dissolved air flotation process (PosiDAF) that uses polymer-modified bubbles, at pilot-scale for the treatment of waste stabilisation pond samples rich in algae. It was found that PDADMAC in PosiDAF gave comparable removal to that achieved using conventional DAF at .95% cell separation. Furthermore, the float layer was more uniform and thicker with up to 8% solid contents compared to conventional DAF, which comprised discrete floc clusters with an average solid concentration of ∼4.1%. In contrast to the use of PDADMAC, the application of the HMP did not achieve similarly good separation at pilot scale. It was hypothesised that this may be due to the micellisation of the HMP on the bubble surface, creating unstable bubbles that coalesced and prevented polymer-bubble-cell interactions, which are crucial for effective cell separation. On comparison of the costs of PosiDAF and conventional DAF, it was found that PosiDAF resulted in cost-savings of up to 74% due to low chemical consumption. In summary, PosiDAF reduced chemical cost and increased solid contents in the metal-free float.Article Citation - WoS: 11Citation - Scopus: 12Phytohormone Release by Three Isolated Lichen Mycobionts and the Effects of Indole-3 Acid on Their Compatible Photobionts(Springer, 2020) Candotto Carniel, Fabio; Muggia, Lucia; Ametrano, Claudio Gennaro; Kranner, Ilse; Çimen, Tuğçe; Pichler, Gregor; Stoggl, Wolfgang; Trippel, DanielaEvidence is emerging that phytohormones represent key inter-kingdom signalling compounds supporting chemical communication between plants, fungi and bacteria. The roles of phytohormones for the lichen symbiosis are poorly understood, particularly in the process of lichenization, i.e. the key events which lead free-living microalgae and fungi to recognize each other, make physical contact and start developing a lichen thallus. Here, we studied cellular and extracellularly released phytohormones in three lichen mycobionts, Cladonia grayi, Xanthoria parietina and Tephromela atra, grown on solid medium, and the effects of indole-3-acetic acid (IAA) on their respective photobionts, Asterochloris glomerata, Trebouxia decolorans, Trebouxia sp. Using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS) we found that mycobionts produced IAA, salicylic acid (SA) and jasmonic acid (JA). IAA represented the most abundant phytohormone produced and released by all mycobionts, whereas SA was released by X. parietina and T. atra, and JA was released by C. grayi only. With a half-life of 5.2 days, IAA degraded exponentially in solid BBM in dim light. When IAA was exogenously offered to the mycobionts' compatible photobionts at "physiological" concentrations (as released by their respective mycobionts and accumulated in the medium over seven days), the photobionts' water contents increased up to 4.4%. Treatment with IAA had no effects on the maximum quantum yield of photosystem II, dry mass, and the contents of photosynthetic pigments and alpha-tocopherol of the photobionts. The data presented may be useful for designing studies aimed at elucidating the roles of phytohormones in lichens.Article Citation - Scopus: 1Effect of Atrazine on Algal Contamination and Sugarcane Shoots During Photoautotrophic Micropropagation(American Society of Agricultural Engineers, 2003) Ertürk, Handan; Walker, Paul N.A laboratory procedure was developed for obtaining and maintaining photoautotrophic cultures ofsugarcane shoots in vitro for three generations. Algae contamination in vessels was a problem for photoautotrophic growth under septic conditions. Atrazine, a herbicide, was effective in controlling algae at a concentration of 10 ppm, but the growth of shoots in herbicide-treated sugarless Murashige and Skoog (MS) medium decreased to about half of the growth in untreated medium. As a result, atrazine was not considered to be a practical solution for algae control. Additional work is needed to optimize photoautotrophic micropropagation of sugarcane for both septic and aseptic conditions. Photoautotrophic micropropagation of sugarcane may be economical only if culture can be perfected under septic conditions.Article Citation - WoS: 149Citation - Scopus: 180Hydrogen Production From Algal Biomass Via Steam Gasification(Elsevier Ltd., 2014) Duman, Gözde; Uddin, Md. Azhar; Yanık, JaleAlgal biomasses were tested as feedstock for steam gasification in a dual-bed microreactor in a two-stage process. Gasification experiments were carried out in absence and presence of catalyst. The catalysts used were 10% Fe2O3-90% CeO2 and red mud (activated and natural forms). Effects of catalysts on tar formation and gasification efficiencies were comparatively investigated. It was observed that the characteristic of algae gasification was dependent on its components and the catalysts used. The main role of the catalyst was reforming of the tar derived from algae pyrolysis, besides enhancing water gas shift reaction. The tar reduction levels were in the range of 80-100% for seaweeds and of 53-70% for microalgae. Fe2O3-CeO2 was found to be the most effective catalyst. The maximum hydrogen yields obtained were 1036cc/g algae for Fucus serratus, 937cc/g algae for Laminaria digitata and 413cc/g algae for Nannochloropsis oculata.