http://hdl.handle.net/2268.2/13979 Thu, 05 Mar 2026 22:48:30 GMT 2026-03-05T22:48:30Z http://hdl.handle.net/2268.2/17802 Title: Travail de fin d'études: Exploring the supply chain for brewery's by-product recycling: A study on a potential alternative for a brewery's by-product valorization Abstract: The current global challenge of climate change has led to increased attention on sustainable development practices. In response, the circular economy has emerged as an alternative to the linear economy model, seeking to combat waste, CO2 emissions, and resource depletion. In this context, the primary objective of this work was to identify and evaluate various circular alternatives for the valorization of a by-product generated by a Slovenian brewery. The analysis explored different biomass valorization alternatives as a potential path to address the major problem of ever-increasing organic waste production through the promotion of circular economy principles. In addition to the aforementioned analysis, the study also assessed the feasibility of implementing a Black Soldier Fly (BSF) system as an alternative to by-product management. This innovative approach involves the use of brewers' spent grains (BSG) as feed for insect farming, specifically for BSF larvae. The evaluation examined an integral set of criteria including technical, climate change mitigation potential and market assessments for this by-product management strategy within a circular economy framework. The selected approach involved extensive research and data collection, including literature review, interviews with key stakeholders, and a review of existing documentation of the company. This study aims to contribute to the body of knowledge on circular economy and by-product management practices within the brewing industry. By exploring different valorization options, the study advances our understanding of how breweries can effectively manage their by-products and move towards a more sustainable and resource-efficient brewing process. The results of this study provide valuable insights and practical recommendations for breweries to enhance their operations while keeping waste generation and environmental impact to a minimum. Wed, 21 Jun 2023 22:00:00 GMT http://hdl.handle.net/2268.2/17802 2023-06-21T22:00:00Z http://hdl.handle.net/2268.2/17759 Title: Travail de fin d'études: "Purification of stilbenes excreted by plant cells using the adsorption technology" Abstract: The present study investigated the adsorption of five stilbene molecules (E-resveratrol, labruscol, laechinol, ε-viniferin, and δ-viniferin) from the fermentation broth of grapevine cells on polymeric macroporous resins. Firstly, five different resins (Amberlite XAD-7, XAD-4, XAD-6, XAD-1180, and FPX66) were tested for the adsorption of stilbenes. XAD-7 was chosen as the optimum adsorbent because it displayed the highest adsorption and desorption capacities of total stilbenes (86.94 ± 4.90 mg/g and 74.28 ± 0.38 mg/g, respectively). Then, the adsorption kinetics were investigated using the XAD-7 resin and it was concluded that the process follows a pseudo-second order kinetic model, and that the intraparticle diffusion of the stilbenes within the adsorbent’s pores limits the adsorption of approximately 10% of total stilbenes. Following this, the adsorption isotherm curves were well fitted to a multicomponent Langmuir model with competition. The isotherm model showed that the maximum adsorption capacity could be at qmax = 0.302 mmol/g, which is quite close to the real adsorption capacity of qeq = 0.271 mmol/g (79.98 ± 4.81 mg/g). ε-Viniferin presents the highest affinity for XAD-7, followed by labruscol, δ-viniferin, E-resveratrol, and laechinol. Next, the dynamic operation mode was studied using fixed-bed column adsorption. The dynamic experiments showed the process to be significantly influenced by bed height. For a constant flowrate of 0.3 mL/min, higher bed lengths were more efficient, and the breakthrough point was delayed. Finally, a maximum desorption capacity of the five stilbenes was observed at 70% (v/v) ethanol solution (59.74 ± 0.14 mg/g) and in a ratio of 160:1 (desorption solution:mass of adsorbent). Using XAD-7 resin to adsorb the targeted compounds coupled with an optimized washing step of the resin beads, increased the weight content (purity) of stilbenes by 4.6 times (from 5 ± 0.05 % to 23.19 ± 0.31 w/w %). Wed, 21 Jun 2023 22:00:00 GMT http://hdl.handle.net/2268.2/17759 2023-06-21T22:00:00Z http://hdl.handle.net/2268.2/17740 Title: Travail de fin d'études: "Control mechanism and recommendations for eliminating a predatory contaminant in Chlorella cultures." Abstract: Extensive research spanning several years has focused on exploring the potential of Chlorella as a large-scale biomass source for various applications, including food, fertilizers, pharmaceuticals, chemical compounds, bioremediation, and energy production. However, a significant challenge arises from the susceptibility of Chlorella cells to being consumed by predators, resulting in decreased productivity. One particularly destructive predator in commercial Chlorella cultures is Poterioochromonas malhamensis, a mixotrophic flagellate known for rapidly causing the collapse of microalgal mass cultivation within a short period. Consequently, there is an urgent need for effective and safe methods to control and prevent contamination by the predatory organism. In this study, we explored the cultivation of Chlorella vulgaris in an ammonium nitrogen (AN) medium under alkaline conditions as a means to control P. malhamensis in laboratory conditions. Ammonium bicarbonate (NH4HCO3) was used as the source of AN. Our results demonstrated that NH4HCO3 concentrations corresponding to AN concentration of 120, 240, and 360 mg/L effectively controlled P. malhamensis, resulting in a remarkable 95% mortality within 24 hours. Furthermore, the NH4HCO3 concentration corresponding to a AN concentration of 240 mg/L exhibited the highest biomass concentration, comparable to that of the control group conducted in nitrate medium. To validate the effectiveness of the method, co-cultures of C. vulgaris and P. malhamensis was conducted using an AN concentration of 240 mg/L. The biomass yield of C. vulgaris in treated co-cultures with AN was similar to that of the monocultures conducted in nitrate medium, while the untreated co-cultures experienced a contamination event and complete crash. Considering the AN toxicity to P. malhamensis, the relative safety to C. vulgaris, and its low cost and chemical safety, cultivation of Chlorella in NH4HCO3 under alkaline pH conditions emerges as a technically and economically feasible, as well as safe approach for controlling P. malhamensis contamination in outdoor, large-scale cultivation of Chlorella. Tue, 20 Jun 2023 22:00:00 GMT http://hdl.handle.net/2268.2/17740 2023-06-20T22:00:00Z http://hdl.handle.net/2268.2/17737 Title: Travail de fin d'études: "Environmental impact assessment" Abstract: This research aimed to find the routes for the production of bio-phenol and make a comparison with the use of consequential life cycle assessment, to distinguish the best pathways from an environmental performance point of view. Due to the time limitation, and infancy of the technologies studied, the work still shows potential for further improvements. Initially, different possibilities were studied to find alternatives to the petrol-based phenol. These options were categorized into lignin-first and bio-oil pathways. For each of these categories, sub-groups were found, and more specifically, RCF, AAF, and organosolv were presented as three lignin-first methods. Both for the lignin-first and bio-oil scenarios, the process flow was found through literature review and based on previous works conducted in the field. After development and assessing various possibilities, RCF and bio-oil scenarios were selected to be further studied, and to conduct the LCA for these methods. Next, the detailed process flow was identified for each, followed by the mass and energy balances for both. Biomasses were selected based on the previous works, which are birch, willow, and poplar. LCI was done and needed information were gathered and completed so that the impact assessment could be done. After completion of the process development and LCI step, the modelling was done through activity browser. Six impact categories were studied including: Global Warming Potential (GW100), eutrophication: marine, eutrophication: fresh water, land use, water use, and particulate matter. For all these impact categories, the results are presented for all the biomasses. Among the 6 impact categories studied here, Biomass cultivation and RCF reaction were the ones that appeared as the main contributors three and two times, respectively. Based on table3, these two steps are considered as the hot spots of the process, and further works can be done to improve their environmental impacts. RCF reaction is still not very well-developed and thus, further research and studies are needed to make the process more efficient and less polluting. One of the key conclusions from this work is that (as shown in the result), there is no meaningful difference from an environmental performance point of view between birch, poplar, and willow when they are used as the raw material for RCF process. Sun, 18 Jun 2023 22:00:00 GMT http://hdl.handle.net/2268.2/17737 2023-06-18T22:00:00Z