Master Degree / Yüksek Lisans Tezleri
Permanent URI for this collectionhttps://hdl.handle.net/11147/3008
Browse
3 results
Search Results
Master Thesis Screening Spirulina Stranins for Protein Productivity Based on Cultivation Under Photobioreactor Conditionsy(01. Izmir Institute of Technology, 2022) Binkanat, Tahir Burak; Özkan, Altan; Büyükkileci, Ali OğuzSpirulina is an industrially produced algae for consumption as a nutritional supplement owing to its exceptionally high protein content. The delivery of the desired metabolite profiles highly depends on selecting the correct strains for growth. In this regard, the information in the literature is limited as the strains cultivated industrially are unknown, and the strains of academic research were mostly locally isolated or procured from local sources. The current study is the first step of research activities planned to assess the large-scale production potential of Spirulina in Izmir. Thus in this work, Spirulina platensis 2340, Spirulina maxima 84.79, Spirulina platensis 85.79, Spirulina platensis 86.79, and Spirulina platensis 29 were screened for biomass and protein productivity during cultivation under standardized process conditions of a bubble column photobioreactor. The final biomass concentrations were strain specific and ranged from 1.2 to 1.9 g/L. An inverse relationship existed between the logistic model-based final biomass concentrations and the production rate constants. Thus, the peak productivities were more evenly distributed and ranged between 0.15 to 0.20 g/L-day. SP 29 had the ideal protein content vs. cultivation time profile as it was consistently high and varied in the narrow range of 60 to 64%. Higher protein contents could be reached with the other strains, but they also had higher variations during the growth period. The final protein concentrations varied from 0.4 g/L to 1.4 g/L. The highest peak productivity obtained was about 0.11 g/L-day, which could be obtained by three of the strains. The results clearly show the importance of strain selection for sustaining protein-rich biomass production with Spirulina.Master Thesis Production of Bio-Oil From Haelnut Shell Waste by Using Supercritical Ethanol, Acetone and Their Mixtur(Izmir Institute of Technology, 2018) Dal, Orkan; Yüksel Özşen, Aslı; Yüksel Özşen, AslıThe goal of this study was to investigate effect of reaction temperature, reaction time and solvent ratio (ethanol/acetone v/v%) on bio-oil yield, solid conversion and product distribution. Direct thermochemical biomass degradation to obtain bio-oil by using organic solvents is not a new process type, and it has some advantages over hydrothermal liquefaction technique. However, in literature, to our best knowledge, there is no study about hazelnut shell decomposition by using ethanol, acetone and their mixtures at sub/supercritical conditions. In this study, experiments were carried out between 220-300 °C, at three different temperatures (30, 60 & 90 min) for five different solvent ratios. Highest solid conversion achieved at 300 °C by using pure ethanol was 64.2%, whereas highest bio-oil yield was found as 44.2% at 300 °C with 50/50 (EtOH/Ac: v/v). Ethanol and acetone showed different characteristics during the experiments and their effect on the conversion and bio-oil yield were discussed. Statistical analysis showed that time, temperature, ratio and temperature-time are affecting parameters for the conversion and bio oil yield while time-ratio and temperature-ratio are not. According to GC-MS results, product distribution changed with respect to solvent type and ratio.Master Thesis Hydrothermal Treatment of Biomass in Hot-Pressurized Water(Izmir Institute of Technology, 2015) Dadenov, Saken; Yüksel Özşen, Aslı; Emrullahoğlu, MustafaThe aim of this study is to observe conversion of cellulose, which is the main compound of biomass, into its building-block chemicals in hot-pressured water as reaction medium with no addition of organic solvents. Water in liquid state under temperature and pressure above boiling point and below the critical point (374. 15 ºC and 22.1 MPa) is called as hot-pressurized water (or sub-critical water). Nowadays the biomass has great attention across the World as renewable source of energy, at the background of the quickly growing energy demand, since it is widely available and cheap. This technology is totally environmentally friendly and uses water as a reaction medium. As well known, since plant biomass contains up to 50% cellulose, it was decided to use it as a model compound in this study. Decomposition of cellulose leads to formation of various compounds. Among them levulinic acid is the most attractive chemical. Moreover, this acid marked as “Top 12 Building Blocks” of most perspective chemicals and obtaining from biomass by hydrothermal treatment is not widely studied. During this study, different reaction parameters such as temperature, pressure, reaction time and external oxidizer addition were studied to clarify their effects on cellulose decomposition and product yields to achieve the highest selectivity of the desired product. Addition of H2SO4 led to increase cellulose conversion up to 73% at 200 oC with a H2SO4 concentration of 125 mM at 60 min reaction time. Under same conditions, the yield of levulinic acid was successfully achieved to 38% after 60 min.