Brewer's spent grain (BSG) is the most abundant by-product of the brewing industry and its main application is limited to low-value cattle feed. Since BSG contains 20 to 25% of proteins, it has the potential to provide a new protein source to the food industry. In this research, an ultrasound-assisted enzymatic extraction was designed to extract protein hydrolysates from BSG. Original BSG and ultrasound pretreated BSG were hydrolyzed under different enzyme (Alcalase) loadings and incubation times. Centrifugation was applied to separate solubilized proteins from insoluble BSG residue. When the enzyme loading increased from 1 to 40 uL /g BSG, the solubilized proteins increased from 34% to 64.8%. The application of ultrasound further increased the solubilized proteins from 64.8% to 69.8%. Solubilized proteins from ultrasound pretreated BSG was significantly higher (p < 0.05) than that from the original BSG. Particle size distribution analysis showed that the application of ultrasound pretreatment reduced the BSG particle size from 331.2 to 215.7 um. Scanning electron microscopy images revealed that the BSG particle surface was partially ruptured by the ultrasound pretreatment. These two phenomena might have contributed to the increased protein separation efficiency with ultrasound pretreatment. The solubility (pH 1.0 to 11.0) of protein hydrolysate increased by the application of ultrasound and the ultrasound did not lead to the change of the amino acid composition of the separated protein hydrolysates. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile, the protein was degraded to peptides which had molecular weights lower than 15 kDa. The color of the separated protein hydrolysates by enzymatic hydrolysis was brighter and lighter than the original BSG. The application of ultrasound did not affect the color of the separated protein hydrolysates. Overall, the ultrasound pretreatment prior to enzymatic hydrolysis enhanced the extraction of proteins from BSG in terms of higher protein separation efficiency, lower enzyme loadings, and reduced incubation time. This study developed a novel and green method to effectively extract value-added protein hydrolysates from the low-value food processing byproducts. / MSLFS / Brewer’s spent grain (BSG) is the most abundant waste generated by beer industries after beer production and it is mainly used to feed cattle. Since BSG contains 20 to 25% proteins, it has the potential to provide a new protein source to food industries. The aim of this research is to study if the ultrasound technology can assist the enzymatic extraction of proteins from BSG. If it can, the cost of the protein extraction from BSG can be reduced. In this research, the original BSG and the BSG pretreated with ultrasound were incubated under different enzyme loadings and incubation times. The protein-rich liquid was separated from fiber-rich solids using a centrifuge. When the enzyme loading increased from 1 to 40 L /g BSG, 34% to 64.8% of proteins were separated from the original BSG. The application of ultrasound further increased the solubilized proteins from 64.8% to 69.8%. For the BSG pretreated with ultrasound, there were significantly more proteins separated from BSG compared to the original BSG. Particle size of the original BSG and the ultrasound pretreated BSG was measured, and the results showed that the application of ultrasound pretreatment decreased the BSG particle size from 331.2 to 215.7 µm. Scanning electron microscopy images were taken to investigate the effect of ultrasound on the surface of BSG particles. Based on the photos, we found that the BSG particle surface was partially broken by the ultrasound pretreatment. The surface was rough and contained large amounts of holes instead of being flat and smooth observed without ultrasound. Therefore, there were more locations for the enzyme to attack. These two phenomena might have contributed to extracting more proteins from BSG. Protein solubility (pH 1.0 to 11.0) increased by the application of ultrasound. The nutritional value of the protein extracted was not altered by the ultrasound. The extracted protein hydrolysates had a small molecular weight and the application of ultrasound did not affect the color of the extracted protein hydrolysates. The ultrasound pretreatment prior to enzymatic hydrolysis increased the extraction of proteins from BSG, decreased the enzyme consumption and incubation time. This study developed a novel and green method to effectively extract value-added protein hydrolysates from the low-value food processing byproducts.

Brewer's spent grain (BSG) is a main by-product of beer manufacturing and is rich in nutrients including 15-30% protein, making it a potentially valuable protein source for human food. Current challenges of extracting protein from BSG include low yields and high manufacturing costs, but the rising trend of plant-based diets for environmental and health reasons increases BSG's appeal. This research proposes an innovative extraction process utilizing wet fractionation and enzymatic purification that targets fiber to effectively separate proteins form BSG. Additionally, the feasibility of BSG protein as a food ingredient is explored, offering a unique approach that limits harsh processing commonly used for protein extraction. The choice of the enzyme (CTec 2 and Viscozyme L), enzyme dose, and incubation time (1, 3, 6, 9, and 24 hrs) were investigated to maximize protein content and recovery and further evaluate processing effects on protein functionality. Following wet fractionation, there was a notable reduction in fiber from 48.6% in the BSG to 22.5% in the filtrate (PRF) on a dry basis. Additionally, the protein content increased from 22.8 to 40.0% from the BSG to the PRF, respectively. The coarse fiber (CF) had an average protein content of 6.30%, highlighting the effectiveness of wet fractionation in enhancing protein recovery from BSG. The optimal enzymatic treatments condition identified was using CTec 2 to degrade fiber at a dose of 6.00% (g enzyme/g solid) for 24 hours. The enzymatic fiber hydrolysis proved to be able to remove lignocellulosic biomass from BSG resulting in a defatted protein concentrate (DPC) with a high protein content (52.8%) along with a high recovery rate (63%). All treatments resulted in protein functionality similar to the two control treatments. Varying fiber hydrolysis conditions did not have a significant effect on the functional properties. Several functional properties were improved using limited hydrolysis (LH) using proteases. LH had negative impacts on foaming stability and emulsifying properties; however, it improved the solubility, foaming capacity, WHC, and OHC of the BSG protein. Potential applications for the DPC include low moisture applications such as protein bars or granola. The DPCs could also have potential use in meat alternatives due to the high WHC and OHC and the need for varying protein solubility in meat alternatives. The LH protein has greater potential in applications such as protein beverages due to the high solubility. This process presents a promising protein extraction approach from BSG, offering producers the flexibility to tailor it to their specific application needs. After obtaining the protein concentrate, additional steps like defatting or limited hydrolysis can be applied to improve the purity and functionality of the result protein. Notably, this approach contributes to sustainable food production by addressing food waste and meeting the rising demand for sustainable protein sources to support the nutritional needs of a growing global population. / Master of Science in Life Sciences / Brewer's spent grain (BSG) is a by-product of beer manufacturing with rich nutrients, including 15-30% protein. It holds potential as a valuable protein source for human food. Current challenges of extracting protein from BSG include low yields and high costs, but the rising trend of plant-based diets for environmental and health reasons increases BSG's appeal. Its abundant availability year-round makes it an attractive option for human food. In this study, an innovative process to extract protein from BSG was explored using wet fractionation to separate the BSG by size. Enzymes were then used to remove remaining fiber. Various enzymes and times were tested to optimize extraction and achieve a high protein content and recovery rate. The protein's physicochemical and functional properties were then evaluated for potential uses in human food. After wet fractionation, nearly half the fiber was removed, and the protein content increased by 17.2%. Using an enzyme called CTec 2 for 24 hours worked best, resulting in a protein concentrate with a high protein content (52.8%) and good recovery (63.0%). Changes in enzyme treatments did not have a significant effect on the protein functional properties. Potential applications for the protein concentrates include low moisture applications such as protein bars or granola due to the poor solubility. The protein concentrates could also have potential use in meat alternatives due to the water and oil holding properties. The low solubility of the protein concentrates was improved using a process called limited hydrolysis making it possible to apply to products like protein beverages. This research highlights BSG's potential as a valuable protein source for protein bars, meat alternatives, and protein beverages. These findings provide a promising approach to utilize BSG as a valuable plant protein source for a healthier and more environmentally friendly food production.

No description available.

O presente estudo teve como objetivo avaliar a produção de etanol pela levedura Pichia stipitis, a partir do hidrolisado hemicelulósico do bagaço de malte (HHBM). Primeiramente estudou-se o efeito da suplementação nutricional do hidrolisado adicionando-se extrato de farelo de arroz (0 a 20% v/v), uréia (0 a 3 g/L) e extrato de levedura (0 a 3 g/L). Os resultados mostraram que o hidrolisado suplementado apenas com extrato de levedura proporcionou os melhores resultados de conversão (YP/S = 0,44 g/g) e produtividade em etanol (QP = 0,33 g/L.h). Em seguida foi avaliado o nível ótimo deste nutriente sobre a bioconversão, sendo confirmada a suplementação do HHBM com 3,0 g/L de extrato de levedura. Após o estabelecimento das condições nutricionais, a levedura foi cultivada em HHBM após o crescimento de 24 horas em meio semissintético, visando aclimatar as células aos inibidores presentes no hidrolisado. Este estudo resultou no aumento das velocidades do processo, sendo 16% sobre a produtividade volumétrica em etanol (QP) e 10% sobre a velocidade de consumo de substrato (QS), quando comparado ao cultivo das células somente em meio semissintético. Na etapa seguinte utilizou-se um planejamento fatorial 22 com face centrada para otimização das condições de pH e concentração inicial de células (X0) na fermentação em HHBM não destoxificado e após a destoxificação com carvão ativado. Foram obtidos modelos para descrever os valores de YP/S e QP na região estudada, sendo que para o HHBM não destoxificado os valores destes parâmetros foram 0,40 g/g e 0,65 g/L.h, respectivamente, em pH 6,4 e X0 = 5,0 g/L (modelo 1). Em HHBM destoxificado, as condições ótimas foram obtidas em pH 6,0 e 1,36 g/L de células (modelo 2), obtendo-se YP/S de 0,40 g/g e QP de 0,46 g/L.h. Nas condições otimizadas foram então realizados ensaios que confirmaram a validade dos modelos 1 e 2, obtendo-se a máxima concentração de etanol (23,4 g/L), YP/S de 0,41 g/g e QP de 0,65 g/L.h em HHBM não destoxificado. Realizouse ensaios para avaliação do efeito do ácido acético sobre a fermentação em meio semissintético por P. stipitis, empregando-se as condições de pH e X0 otimizadas em HHBM não destoxificado (modelo 1) e destoxificado (modelo 2). Este estudo mostrou que nas condições do modelo 1, o ácido acético favoreceu a bioconversão sendo os melhores resultados obtidos na presença deste ácido (YP/S = 0,47 g/g e QP = 1,08 g/L.h). Por outro lado, nas condições do modelo 2, os valores de YP/S foram similares, enquanto que com a adição de ácido acético ao meio de fermentação, o valor de QP foi reduzido em 53%. Na fermentação em biorreator, o emprego das condições otimizadas em frascos (pH 6,4 e 5,0 g/L de células) resultaram em valores de QP 48% inferiores ao obtido em frascos (0,65 para 0,44 g/L.h), entretanto YP/S foi apenas 10% inferior (0,41 para 0,37 g/g). No presente estudo, conclui-se que a suplementação nutricional do HHBM e a otimização das condições de pH e X0 resultaram em valores promissores para os principais parâmetros da fermentação por P. stipitis, ressaltando o potencial deste hidrolisado em processos biotecnológicos para produção de etanol. / This study aimed to evaluate the ethanol production by Pichia stipitis in brewer\'s spent grain hemicellulosic hydrolysate (BSGHH). Initially, the effect of nutritional supplementation was evaluated by adding rice bran extract, urea and yeast extract. The results showed that supplementation only with yeast extract promoted the highest conversion values (YP/S = 0.44 g/L) and ethanol productivity (QP = 0.33 g/L.h). Additional assays showed that the optimal concentration of this nutrient was 3.0 g/L. To acclimate the cells to inhibitors present in BSGHH the yeast was cultivated in hydrolysate after growth for 24 hours in semisynthetic medium. This study resulted in increased of the process rates, 16% of the ethanol productivity (QP) and 10% on the substrate consumption (QS) when compared to growing cells only in the semisynthetic medium. In the second step a 22 full factorial centeredface design was employed to optimized the conditions of pH and initial cells concentration (X0) in fermentation of hydrolysate undetoxified and after detoxification with activated charcoal. Mathematical models that relate the YP/S and QP were obtained. For non-detoxified BSGHH (model 1) the optimal conditions of pH (6.4) and X0 (5.0 g/L) showed values parameters of 0.41 g/g and 0.65 g/L.h, respectively. In detoxified BSGHH (model 2) the optimum conditions of pH (6.0) and X0 (1.36 g/L), resulted in YP/S and QP values of 0.40 g/g and 0.46 g/L.h, respectively. Under these conditions, the the validity of the models were confirmed. The effect of acetic acid on fermentation by P. stipitis in semisynthetic medium, employing optimized conditions of pH and X0 in model 1 and model 2 was evaluated. The results showed that under the conditions of model 1 and in a concentration of 2,9 g/L, the acetic acid favored the bioconversion by P. stipitis, increasing the YP/S (15 %) and QP (66 %). On the other hand, in the conditions of the model 2 the YP/S values were similar, whereas the QP values were reduced by 53% when the acetic acid was added. By using these optimized conditions in bioreactor fermentation it was obtained the ethanol productivity was approximately 48% lower (0.65 to 0.44 g/L.h), however the ethanol production was similar as compared to fermentation flasks. It is possible conclude that the HHBSG requires nutritional supplementation and that the optimized conditions of pH and initial cells concentration can be used as a strategy in order to raising the fermentation parameters.

Sustainable development is a growing concern for inhabitants of the planet earth. Consumption of fossil sources keeps up the depletion of nature’s capital and causes environmental impacts. One solution to have a sustainable society is to reduce the dependency on fossil fuels and substitute them by renewable energy sources. Among different types of renewable energy, biofuels have great potential for development and improvement. Though, the production of biofuels is criticized by many experts from the energy efficiency, environmental and economical points of view. Biogas as one type of first generation biofuels is achieved from the wastes and by-products of other industries, and can be used as a transportation fuel in the form of biomethane. The use of by-products may give added value as inputs to the biogas production process, a process which may be called "upcycling." The aim of upcycling is to convert wastes into new materials with higher quality or higher environmental value in order to reduce the consumption of raw materials which results in decreasing of energy usage and environmental impacts The aim of this thesis is to study the possibility of a biogas plant to act as an upcycler of wastes and by-products through anaerobic digestion process by the use of exergy analysis and economic evaluation. An imaginary biogas plant which uses a major by-product of brewing industry, i.e. Brewer’s Spent Grain (BSG), is considered to quantify the added value by biogas production process. The results of the exergy analysis show that the exergy of the input BSG (78,320 MJ) is upgraded into two main products as biomethane (47,430 MJ) and biofertilizer (37,026 MJ) with a total exergy amount of 84,456 MJ. On the other hand, the economic analysis of the studied biogas production process indicates that the biogas plant has the added value for the input material. In the economic analysis, the annual costs and benefits of the biogas production is calculated. The results show that the production of biomethane and biofertilizer from the by-product of brewing industry is profitable. However, the price of input BSG and also the variation price of the biofertilizer in different seasons, have great impact on the economy of a biogas plant. The outcomes from exergy and economic analysis are indicated that the biogas production process is an "upcycling" process which has the added value for the inputs, from both economic and quality points of view. The exergy and economic evaluation may be used as indicators of the sustainable development, but only increasing the exergy and the economic value of a production process alone should not be considered as the sustainability of a system.

O presente estudo teve como objetivo avaliar a produção de etanol pela levedura Pichia stipitis, a partir do hidrolisado hemicelulósico do bagaço de malte (HHBM). Primeiramente estudou-se o efeito da suplementação nutricional do hidrolisado adicionando-se extrato de farelo de arroz (0 a 20% v/v), uréia (0 a 3 g/L) e extrato de levedura (0 a 3 g/L). Os resultados mostraram que o hidrolisado suplementado apenas com extrato de levedura proporcionou os melhores resultados de conversão (YP/S = 0,44 g/g) e produtividade em etanol (QP = 0,33 g/L.h). Em seguida foi avaliado o nível ótimo deste nutriente sobre a bioconversão, sendo confirmada a suplementação do HHBM com 3,0 g/L de extrato de levedura. Após o estabelecimento das condições nutricionais, a levedura foi cultivada em HHBM após o crescimento de 24 horas em meio semissintético, visando aclimatar as células aos inibidores presentes no hidrolisado. Este estudo resultou no aumento das velocidades do processo, sendo 16% sobre a produtividade volumétrica em etanol (QP) e 10% sobre a velocidade de consumo de substrato (QS), quando comparado ao cultivo das células somente em meio semissintético. Na etapa seguinte utilizou-se um planejamento fatorial 22 com face centrada para otimização das condições de pH e concentração inicial de células (X0) na fermentação em HHBM não destoxificado e após a destoxificação com carvão ativado. Foram obtidos modelos para descrever os valores de YP/S e QP na região estudada, sendo que para o HHBM não destoxificado os valores destes parâmetros foram 0,40 g/g e 0,65 g/L.h, respectivamente, em pH 6,4 e X0 = 5,0 g/L (modelo 1). Em HHBM destoxificado, as condições ótimas foram obtidas em pH 6,0 e 1,36 g/L de células (modelo 2), obtendo-se YP/S de 0,40 g/g e QP de 0,46 g/L.h. Nas condições otimizadas foram então realizados ensaios que confirmaram a validade dos modelos 1 e 2, obtendo-se a máxima concentração de etanol (23,4 g/L), YP/S de 0,41 g/g e QP de 0,65 g/L.h em HHBM não destoxificado. Realizouse ensaios para avaliação do efeito do ácido acético sobre a fermentação em meio semissintético por P. stipitis, empregando-se as condições de pH e X0 otimizadas em HHBM não destoxificado (modelo 1) e destoxificado (modelo 2). Este estudo mostrou que nas condições do modelo 1, o ácido acético favoreceu a bioconversão sendo os melhores resultados obtidos na presença deste ácido (YP/S = 0,47 g/g e QP = 1,08 g/L.h). Por outro lado, nas condições do modelo 2, os valores de YP/S foram similares, enquanto que com a adição de ácido acético ao meio de fermentação, o valor de QP foi reduzido em 53%. Na fermentação em biorreator, o emprego das condições otimizadas em frascos (pH 6,4 e 5,0 g/L de células) resultaram em valores de QP 48% inferiores ao obtido em frascos (0,65 para 0,44 g/L.h), entretanto YP/S foi apenas 10% inferior (0,41 para 0,37 g/g). No presente estudo, conclui-se que a suplementação nutricional do HHBM e a otimização das condições de pH e X0 resultaram em valores promissores para os principais parâmetros da fermentação por P. stipitis, ressaltando o potencial deste hidrolisado em processos biotecnológicos para produção de etanol. / This study aimed to evaluate the ethanol production by Pichia stipitis in brewer\'s spent grain hemicellulosic hydrolysate (BSGHH). Initially, the effect of nutritional supplementation was evaluated by adding rice bran extract, urea and yeast extract. The results showed that supplementation only with yeast extract promoted the highest conversion values (YP/S = 0.44 g/L) and ethanol productivity (QP = 0.33 g/L.h). Additional assays showed that the optimal concentration of this nutrient was 3.0 g/L. To acclimate the cells to inhibitors present in BSGHH the yeast was cultivated in hydrolysate after growth for 24 hours in semisynthetic medium. This study resulted in increased of the process rates, 16% of the ethanol productivity (QP) and 10% on the substrate consumption (QS) when compared to growing cells only in the semisynthetic medium. In the second step a 22 full factorial centeredface design was employed to optimized the conditions of pH and initial cells concentration (X0) in fermentation of hydrolysate undetoxified and after detoxification with activated charcoal. Mathematical models that relate the YP/S and QP were obtained. For non-detoxified BSGHH (model 1) the optimal conditions of pH (6.4) and X0 (5.0 g/L) showed values parameters of 0.41 g/g and 0.65 g/L.h, respectively. In detoxified BSGHH (model 2) the optimum conditions of pH (6.0) and X0 (1.36 g/L), resulted in YP/S and QP values of 0.40 g/g and 0.46 g/L.h, respectively. Under these conditions, the the validity of the models were confirmed. The effect of acetic acid on fermentation by P. stipitis in semisynthetic medium, employing optimized conditions of pH and X0 in model 1 and model 2 was evaluated. The results showed that under the conditions of model 1 and in a concentration of 2,9 g/L, the acetic acid favored the bioconversion by P. stipitis, increasing the YP/S (15 %) and QP (66 %). On the other hand, in the conditions of the model 2 the YP/S values were similar, whereas the QP values were reduced by 53% when the acetic acid was added. By using these optimized conditions in bioreactor fermentation it was obtained the ethanol productivity was approximately 48% lower (0.65 to 0.44 g/L.h), however the ethanol production was similar as compared to fermentation flasks. It is possible conclude that the HHBSG requires nutritional supplementation and that the optimized conditions of pH and initial cells concentration can be used as a strategy in order to raising the fermentation parameters.

Unwanted uranium released in the aquatic environment from uranium mining and nuclear fuel industry has become a growing threat to human health and environment safety due to its radiological and chemical toxicity. Biosorbents from agro-industrial waste are the most preferred materials for the removal of uranium from the wastewater due to their good cost-to-performance ratio. Brewer’s spent grain (BSG), a widely produced by-product from the beer brewery industry, is an inexpensive and readily available feedstock for the production of uranium biosorbents. In the current work, the use of BSG as a promising starting feedstock for low-cost and efficient adsorbents with high adsorption capacity, fast kinetics, selectivity, and reusability, is investigated. Functionalization methods such as thermal treatment, chemical modification (oxidation), and polymer grafting were explored, and the selectivity was tuned using surface ion-imprinting technology. The adsorption performance of adsorbents prepared from BSG was tested under various conditions for practical application, and structure affinity principles were derived from the characterization, data modeling and experimental results (Fig. 1). In the first part of this work, BSG is successfully converted into altered BSG (ABSG), an effective biosorbent, by mild hydrothermal treatment approach (150 ℃, 16 h). Compared with the conventional hydrothermal carbonation method (up to 250 ℃), the current method is carried out at a significantly lower temperature without any additional activation process, which minimizes the energy consumption and environmental impact during the treatment. Maillard reaction plays an important role in increasing the adsorption capacity by forming various Maillard reaction products (methylglyoxal-derived hydroimidazolone-1 with the highest content) and melanoidins with a large number of functional groups. In addition, other pathways such as dehydration, decarboxylation, aromatization and oxidation also contribute to the increased adsorption capacity. Therefore, the content of carboxyl groups in ABSG increases up to 1.46 mmol/g with maximum adsorption capacities for La(Ⅲ), Eu(Ⅲ), Yb(Ⅲ) (pH = 5.7), and U(Ⅵ) (pH = 4.7) of 38, 68, 46 and 221 mg/g, respectively (estimated by the Langmuir model). Moreover, FT-IR spectra show that both O- and N-containing functional groups are involved in the adsorption of studied ions. The second part of this work demonstrates for the first time the successful oxidization of BSG using 85 wt% H3PO4 and NaNO2, increasing the carboxyl groups content from 0.15 mmol/g for BSG to 1.3 mmol/g for oxidized BSG (OBSG). OBSG exhibits fast adsorption kinetics in 1 h and an adsorption capacity for U(Ⅵ) of 297.3 mg/g (c0(U) = 900 mg/L, pH = 4.7), which is superior to other biosorbents reported in the literature. Possible adsorption mechanisms are based on ion-exchange between UO22+ and H+ released from carboxyl groups, and the complexation of UO22+ with the two oxygen atoms of carboxyl groups. For practical application, adsorption/desorption studies show that OBSG retains 60% of original adsorption capacity (167 mg/g) with a desorption ratio of 89% after 5 adsorption/desorption cycles. Evaluation of OBSG performance in simulated seawater (10.8 mg/g, c0(U) = 10 mg/L, 193 mg/L NaHCO3 and 25.6 g/L NaCl, pH0 = 7.7) indicates a potential usage at low concentration, high salinity, and in the presence of carbonate. In the third part of this work, brewer’s spent grain supported superabsorbent polymers (BSG-SAP) with various cross-linking density are prepared for the first time via one-pot swelling and graft polymerization of acrylic acid (AA) and acrylamide as low-cost and environmentally friendly adsorbents. A 7 wt% NaOH solution was used as a swelling agent for BSG and as a neutralization agent for AA without generating alkaline effluents. The use of BSG and graft polymerization can significantly increase the available hydroxyl, carboxyl and amide groups, resulting in a highly cross-linked and highly hydrophilic three-dimensional polymer network of BSG-SAP. The BSG-SAP (BSG-SAP-H) prepared with high cross-linking density exhibits better properties with exceptional adsorption capacity for U(VI) of 1465 mg/g (estimated by the Toth model) at pH0 = 4.6 within 45 min. It also shows good selectivity for U(VI) in the presence of several metal ions (V(V), K(I), Na(I), Mg(II), Zn(II), Co(II), Ni(II), and Cu(II)) with selectivity coefficients (SU) higher than 72%. In simulated seawater, BSG-SAP-H showed higher adsorption capacity (17.6 mg/g for c0(U) = 8 mg/L, pH0 = 8) compared to the currently reported adsorbents based on natural polymers. In the experiments with the fixed bed column (c0(U) = 30 mg/L), the uranyl ions could be concentrated up to 15 folders in U(VI)-spiked water and up to 13 folds in simulated seawater. Moreover, after four cycles, BSG-SAP-H was able to maintain 80% of adsorption capacity in U(VI)-spiked water (254.4 mg/g) and 90% in simulated seawater (37.4 mg/g). FT-IR and 13C solid-state NMR spectra show the function of amide groups for U(VI) adsorption, the bidentate binding structure between UO22+ and the carboxyl groups, and the cation exchange between Na+ in BSG-SAP and UO22+. The fourth part of this work describes a new strategy for the preparation of surface ion imprinted brewer’s spent grain (IIP-BSG) using binary functional monomers (2-hydroxyethyl methacrylate and diethyl vinylphosphonate) for selective removal of U(VI). A high monomer/template molar ratio of 500:1 is used to ensure high site accessibility and easy template removal. IIP-BSG exhibits a maximum U(VI) adsorption capacity of 165.7 mg/g (pH0 = 4.6, estimated by the Sips model), a high selectivity (SU > 80%) for U(VI) in the presence of an excess amount of Eu(III) (Eu/U molar ratio = 20), and good tolerance to salinity (47.4 mg/g for U(VI) at ionic strength = 1 mol/L and c0(U) = 0.5 mM = 120 mg/L). After 5 adsorption and desorption cycles, IIP-BSG retains 90% of its adsorption capacity (36.9 mg/g) and high selectivity (SU > 92%) in binary U(VI)/Eu(III) solution (c0 = 0.5 mM = 120 mg/L). In addition, FT-IR spectra show the electrostatic interaction and a coordination of uranyl ions by carboxyl and phosphoryl groups, the site energy distribution theory shows the predominant contribution of high-energy (specific) sites during selective adsorption, and the kinetic model shows that the internal mass transfer is the rate-determining step of U(VI) adsorption. In the last part of this work, the additional tests were performed for BSG and its derived adsorbents to evaluate their potential for practical application. BSG and most of its derived adsorbents retain 90% of their adsorption capacity after aging in water for 6 days, except for ABSG (60% decrease in adsorption capacity). IIP-BSG shows efficient separation of U(VI)/Ln(Ⅲ) (e.g. La(III), and Nd(III), Sm(III)) in weakly acidic nuclear wastewater (pH0 = 3.5) and U(VI) concentration in carbonate-rich-mine water (e.g. Schlema mine water, pH0 = 7.1) and tailings water (e.g. Helmsdorf tailings water, pH0 = 9.8), demonstrating a high potential for practical use. Selectivity of IIP-BSG is also given for acidic mine water (e.g. Königstein mine water, pH0 = 2.6). In addition, the unmodified BSG and BSG-SAP-H could effectively remove uranyl ions from acidic mine water with high selectivity. In particular, the cost efficiency and the availability of unmodified BSG make it of great interests for the remediation of uranium containing acidic mine water (Table 1).

Brewer's spent grain (BSG) is the major byproduct generated by the brewing industry, which contains 14–30% protein and 50–70% of fiber. Currently, BSG is predominantly used as low-value cattle feed or buried in landfills, which is a considerable loss of valuable resources, leading to economic loss and environmental problems. Although research has been done on BSG valorization, the studies are limited to producing a single product (e.g., polyphenols, ethanol, or active carbon) and without further utilization of the produced products. Besides, the economic information available about the production of value-added products from BSG is insufficient. The overall goal of this research is to develop an integrated process to convert BSG into value-added protein-rich feedstuff and cellulose absorbent. The objectives of the research detailed here were to 1) develop a process to simultaneously produce protein-rich (PP) and fiber-rich products (FP) from BSG, 2) assess the replacement of fishmeal with PP in shrimp feed, 3) evaluate the economics of the overall process of PP production at a commercial scale, and 4) explore the potential use of cellulose adsorbent obtained from the FP in removing heavy metals from contaminated water. To attain these objectives, BSG was first subjected to a wet fractionation process to produce PP and FP using different chemical/biological treatments, where the effects of sodium hydroxide, sodium bisulfite, and a protease (Alcalase) at different concentrations were investigated. Under the optimized conditions, the produced PP contained 46% protein and less than 1% fiber. The effectiveness of using PP to replace fishmeal at increasing levels (10–70%) was then evaluated by performing shrimp feeding trials. The results showed that up to 50% of fishmeal in shrimp feed can be replaced by PP without affecting shrimp growth and feed utilization. Moving forward, a techno-economic analysis was conducted to evaluate the economic feasibility of the production of PP. The experimental conditions and results were input into the process simulation model for determining the mass and energy flows. For a processing plant with a capacity of 590 t wet BSG per day, the minimum selling price of PP to achieve a 5% return was determined to be $1044/t, lower than the price of fishmeal, indicating that the use of PP to replace fishmeal in shrimp feed could potentially reduce shrimp farming cost. The utilization of FP will further improve the economic feasibility of the fractionation process. FP was sequentially treated by dilute acid, alkali, and bleach to produce purified cellulose fibers, which were then modified by 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) oxidation to produce a cellulose adsorbent. The feasibility of the adsorbent in removing heavy metals (especially lead and manganese) from contaminated water was then investigated. Based on the results, the produced cellulose adsorbent showed high adsorption capacities for lead (272.5 mg/g) and manganese (52.9 mg/g). Overall, this study demonstrated that BSG can be upcycled into multiple value-added products via an integrated process. The outcomes of this study not only provide a low-cost and sustainable protein source to the aquaculture industry, and provide a novel adsorbent for the water treatment industry, but also offer alternative ways for the brewing industry to manage BSG. / Doctor of Philosophy / Brewer's spent grain (BSG) is the major byproduct generated by the brewing industry. Currently, BSG is predominantly used as low-value cattle feed or buried in landfills due to its high fiber and low protein contents, which is a considerable loss of valuable resources. Besides, raw BSG contains other nutrients and high water content, the inappropriate management of BSG may introduce environmental concerns. Though technologies have been investigated to valorize BSG by extracting protein from it, the process scaled-up is limited by the high drying costs of wet BSG, heavy chemical consumptions, and a large amount of fiber residue. The overall goal of this research is to develop an integrated process to convert BSG into value-added protein-rich feedstuff and cellulose absorbent. In this study, we developed and optimized a process to produce protein and fiber products from wet BSG. The protein content of the produced protein product was doubled and the fiber content was reduced significantly compared with the raw BSG, which lighted the use of the protein product as an alternative to fishmeal. Fishmeal is an expensive aquafeed ingredient, the aquaculture industry is looking for alternatives to replace it. Herein, we investigated the effectiveness of the protein product as an alternative to fishmeal by conducting shrimp trials. A further economic analysis was conducted to evaluate the economic feasibility of the proposed process for protein and fiber production from BSG. In addition, the fiber product was used for producing a cellulose adsorbent to remove heavy metals from contaminated water. Overall, this study demonstrated that BSG can be upcycled into multiple value-added products via an integrated process. The outcomes of this study not only provide a low-cost and sustainable protein source to the aquaculture industry, and provide a novel adsorbent for the water treatment industry, but also provide alternative ways for the brewing industry to manage BSG.

Aquaculture, the cultivation of aquatic organisms in a controlled environment, offers both economic and nutritional benefits to human society. As there is an increased demand to feed a growing human population, many wild-caught fisheries have struggled due to the overexploitation of resources. Currently, production relies heavily on wild-caught fish to produce fishmeal to feed farm-raised fish. The demand for alternative materials in fish feeds has grown rapidly as fishmeal resources have become limited. Antibiotic resistance emergence in aquaculture systems is another area of concern. Reducing antibiotic use via alternate prophylactic measures to increase host health is an essential area of research; modulation of the host intestinal bacterial community via prebiotics is one possibility. Prebiotics refer to non-digestible food ingredients that are thought to stimulate the growth of beneficial bacteria, consequently benefiting host health by indirectly reducing the possibility of bacterial pathogen proliferation. This occurs through various measures such as competition for space and resources. The intestinal bacterial community has a significant impact on a variety of host factors that include host development, physiology, immunity, and nutrient acquisition. In turn, there are multiple factors impacting the bacterial community, including the presence of pathogens and/or antibiotics, environmental conditions, host genetics, and the diet consumed. To promote environmental sustainability and improve production and animal health in aquaculture, a collaboration was created with Anheuser-Busch of the brewing industry and Maltento, a functional ingredient company. With breweries around the globe, Anheuser-Busch produces consistent, food grade byproducts that are safe for human consumption. Two of the most prevalent brewery byproducts are brewer's spent yeast (BSY) and brewer's spent grain (BSG). BSY contains a variety of beneficial nutrients such as proteins, essential amino acids, and carbohydrates. BSG is high in fiber but low in protein; however, black soldier fly larvae can be cultured on BSG to convert the low-value product into insect biomass to be used in fish feed, as insects themselves are full of beneficial lipids and proteins. The objective of the work presented in this thesis was to evaluate the efficacy of using low-value brewery waste products, converted into high-value feed additives, for aquaculture practices. Specifically, the effects of dietary feed additives on the production, health, and intestinal bacterial community of aquaculture-raised rainbow trout were examined. Inadvertently, benefits of the feed additives on fish subjected to chronic and acute thermal stress were also assessed. Overall, the results of the study found that the feed additives did not significantly change the production efficiency of the rainbow trout, though some increase in growth was observed. When subjected to chronic thermal stress conditions, fish fed the experimental diets outperformed those fed the control diet regarding growth parameters. The intestinal bacterial community of the fish was significantly altered from the beginning of the trial compared to the end of the trial, though differences were not attributed to the feed additives. Instead, the resulting intestinal dysbiosis is believed to have stemmed from the physiological response of the fish to thermal stress conditions. When the fish underwent an acute thermal stress event, causing mortality, fish fed three of the five experimental diets were found to have higher survival rates compared to the control. Ultimately, results of this project suggest that the BSY and BSG-fed insect feed additives may have increased the health and robustness of the fish during a period of thermal stress. However, further research under controlled conditions is needed to evaluate if the observed host health benefits can directly be attributed to the feed additives. / Master of Science / Aquaculture refers to the method of rearing aquatic organism such as fish and shellfish under controlled conditions. Within the food industry, aquaculture is one of the fastest growing sectors, and provides important economic and nutritional benefits to humans. Additionally, aquaculture is an important alternative to fisheries that rely on catching fish from the natural environment. Wild-caught fisheries have struggled due to the overfishing, and unfortunately, many aquaculture practices still rely on wild-caught fisheries to produce fishmeal used in feed for carnivorous fish. Research into alternate protein sources to use in fish feed has been on the rise. Additionally, as the emergence of multi-drug resistant bacteria continues to increase, reducing antibiotic use has become a priority across all fields whether it be healthcare or the food industry. Within aquaculture, using alternative prophylactic measures such as prebiotics to increase animal health and disease resistance could lead to the overall reduction of antibiotic use. Prebiotics are non-digestible food ingredients believed to help the beneficial bacteria within the intestinal track to grow. In turn, the increased numbers of beneficial bacteria reduce the possibility of pathogenic bacteria invading and establishing a presence in the intestinal track. The intestinal microbiome refers to the various organisms, such as bacteria, viruses, and fungi, that live commensally within the host digestive tract. The bacterial community within the intestinal microbiome has many important roles, including effects on host development, physiology, immunity, and nutrient acquisition. Many factors also impact the bacterial community, including the presence of pathogens and/or antibiotics, environmental conditions, host genetics, and the diet consumed. To promote environmental sustainability and improve production and animal health in aquaculture, a collaboration was created with Anheuser-Busch of the brewing industry and Maltento, a functional ingredient company. With breweries around the globe, Anheuser-Busch produces consistent, food grade byproducts that are safe for human consumption. Two of the most prevalent brewery byproducts are brewer's spent yeast (BSY) and brewer's spent grain (BSG). These low-value waste products can consequently be converted into high-value feed additives for use in aquaculture. The objective of the work presented in this thesis was to evaluate the effects of BSY and BSG-fed insect dietary feed additives on the production, health, and intestinal bacterial community of aquaculture-raised rainbow trout. Unintentionally, benefits of the feed additives on fish subjected to chronic and acute high-temperature thermal stress were also explored. Overall, the results of the study found that while the feed additives did not significantly increase the growth of the rainbow trout, benefits were still observed. When subjected to chronically high-water temperatures, fish fed the experimental diets outperformed those fed the control diet regarding growth parameters. The intestinal bacterial community of the fish was significantly altered from the beginning of the trial compared to the end of the trial, though differences are not believed to be caused by the feed additives. Instead, the resulting shift in the bacterial community is believed to have stemmed from the stress-response of the fish triggered by high water temperature. When the fish underwent an acute thermal stress event, which caused mortality, fish fed three of the five experimental diets were found to have higher survival rates compared to the control. Ultimately, results of this project suggest that the feed additives may have increased the health and robustness of the fish while undergoing thermal stress. However, further research under controlled conditions is needed to evaluate if the observed host health benefits can be attributed directly to the feed additives.

Atualmente observa-se um aumento significativo no consumo de cervejas com baixo teor alcoólico e cervejas sem álcool. Existe um crescente interesse por este tipo de produto tanto por parte das indústrias cervejeiras como por parte dos consumidores. Este aumento é principalmente devido a questões de saúde e a razões de segurança no trabalho e nas estradas. Além disso, há países onde o consumo de álcool é proibido por lei. Tendo em vista que o consumidor está em busca de novos produtos com características mais próximas possíveis de uma cerveja convencional, o presente trabalho visa analisar uma nova abordagem para a produção de cerveja lager com baixo teor alcoólico, reutilizando o bagaço de malte, um subproduto da indústria cervejeira, como substituinte de parte do malte. Foram obtidas cervejas com as seguintes proporções de bagaço/malte: 0:100, 25/75, 50/50 e 75/25. Nas cervejas com 50 e 75% de bagaço de malte, observou-se uma redução no tempo de fermentação quando comparadas com a cerveja puro malte. A atenuação real de fermentação das cervejas produzidas também foi menor devido a menor fermentabilidade dos mostos. O teor alcoólico das cervejas obtidas em escala de bancada apresentou valores entre 0,665 e 1,615 % (v/v), o que as caracterizam como cervejas de baixo teor alcoólico A cerveja com 25% de bagaço recebeu as maiores notas na análise sensorial, tendo boa aceitação entre os provadores, e foi escolhida para a produção em escala piloto. O perfil de fermentação da cerveja produzida em escala piloto foi similar ao perfil de fermentação da cerveja produzida em escala de bancada. Também foi realizada uma análise sensorial, comparando a cerveja produzida em escala piloto com duas cervejas comercias. A utilização do bagaço de malte como substituinte do malte na fabricação de cervejas com baixo teor alcoólico é uma estratégia viável, produzindo uma bebida com aceitação sensorial semelhante ao de uma cerveja de baixo teor alcoólico comercial. / Nowadays there has been a significant increase in the consumption of beer with low alcohol content and non-alcoholic beers. There is a growing interest on this type of product by both brewers industries and consumers. This increase is mainly due to health issues and safety reasons at work and on the roads. In addition, there are countries where the consumption of alcohol is prohibited by law. Given that the consumer is looking for new products with characteristics as similar as possible of conventional beer, this study aims to analyze a new approach for the production of lager beer with low alcohol content, by reusing brewer\'s spent grain, a by-product of brewing industry, as a substitute of part of the malt. Beers were obtained with the following proportions of bagasse/malt: 0/100, 25/75, 50/50 and 75/25. In beers with 50 and 75% of bagasse, it was observed a reduction in the fermentation time compared with all-malt beer. The Real Attenuation Fermentation of Beer produced was also lower due to lower fermentability of wort. The beers\' alcohol content obtained in laboratory scale showed values between 0.665 and 1.615% (v/v), which characterize them as low-alcohol beers. Beer with 25% of bagasse received the highest scores in sensory analysis, having a good acceptance among the tasters, therefore it was chosen for the production on a pilot scale. The beer\'s fermentation profile produced on pilot scale was similar to the beer\'s fermentation profile produced in laboratory scale. Sensory analysis was also performed, comparing the beer produced in pilot scale with two commercial beers. The use of brewer\'s spent grain as a substitute in the manufacture of beers with low alcohol content is a viable strategy, producing a beverage with sensory acceptance similar to a commercial low-alcohol beer.