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Resveratrol, a natural organic polyhydroxyphenolic compound, has gained significant attention in the last years given its potential health benefits, including antioxidant, anti-cancer, and anti-inflammatory properties. It can be directly extracted from plants, vegetables, and related products and waste resources, but also chemically/enzymatically/microbially synthesized. However, certain process strategies have some limitations, such as high costs, reduced yield or high energy demand, thus implying significant environmental loads. In this context, the search for more sustainable and circular process schemes is key to the integration of resveratrol into the market value chain of the food, cosmetic and pharmaceutical sectors. The extraction of resveratrol has traditionally been based on conventional methods such as solvent extraction, but advanced green extraction techniques offer more efficient and environmentally friendly alternatives. This review analyses both conventional and green alternative extraction technologies, as well as its bioproduction through microbial fermentation, in terms of production capacity, yield, purity and sustainability. It also presents alternative biorefinery models based on resveratrol bioproduction using by-products and waste streams as resources, specifically considering wine residues, peanut shells and wood bark as input resources, and also following a circular approach. This critical review provides some insight into the opportunities that resveratrol offers for promoting sustainable development and circularity in the related market value chains, and thus provides some criteria for decision making for biorefinery models in which resveratrol is one of the targeted high value-added products. It also identifies the future challenges to promote the inclusion of resveratrol in value chains, with the scale-up of green technologies and its demonstrated economic feasibility being the most prominent

Lignin is a very attractive and abundant biopolymer with the potential to be a biorenewable source of a large number of value-added organic chemicals. The current state-of-the-art methods fail to provide efficient valorization of lignin in this regard without the involvement of harsh conditions and auxiliary substances that compromise the overall sustainability of the proposed processes. Making an original approach from the set of mildest temperature and pressure conditions, this work identifies and explores the capacity of an aqueous solution of the nonvolatile ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) to partially depolymerize technical lignin (Indulin AT) by means of a treatment consisting in the simple contact at ambient temperature and pressure. Among a considerable number of valuable phenolic molecules that were identified in the resulting fluid, vanillin (yield of about 3 g/kg) and guaiacol (yield of about 1 g/kg) were the monophenolic compounds obtained in a higher concentration. The properties of the post-treatment solids recovered remain similar to those of the original lignin, although with a relatively lower abundance of guaiacyl units (in agreement with the generation of guaiacyl-derived phenolic molecules, such as vanillin and guaiacol). The assistance of the treatment with UV irradiation in the presence of nanoparticle catalysts does not lead to an improvement in the yields of phenolic compounds.

Anammox bacteria are widely applied worldwide for denitrification of urban wastewater. Differently, their application in the case of industrial effluents has been more limited. Those frequently present high loads of contaminants, demanding an individual evaluation of their treatability by anammox technologies. Bioreactors setting up and recovery after contaminants-derived perturbations are slow. Also, toxicity is frequently not acute but cumulative, which causes negative macroscopic effects to appear only after medium or long-term operations. All these particularities lead to relevant economic and time losses. We hypothesized that contaminants cause changes at anammox proteome level before perturbations in the engineered systems are detectable by macroscopic analyses. In this study, we explored the usefulness of short-batch tests combined with environmental proteomics for the early detection of those changes. Copper was used as a model of stressor contaminant, and anammox granules were exposed to increasing copper concentrations including previously reported IC50 values. The proteomic results revealed that specific anammox proteins involved in stress response (bacterioferritin, universal stress protein, or superoxide dismutase) were overexpressed in as short a time as 28 h at the higher copper concentrations. Consequently, EPS production was also increased, as indicated by the alginate export family protein, polysaccharide biosynthesis protein, and sulfotransferase increased expression. The described workflow can be applied to detect early-stage stress biomarkers of the negative effect of other metals, organics, or even changes in physical-chemical parameters such as pH or temperature on anammox-engineered systems. On an industrial level, it can be of great value for decision-making, especially before dealing with new effluents on facilities, deriving important economic and time savings.

Surfactants are ubiquitous in formulated products and technologies. As one of the most important commodity chemicals, their remarkable consumption leads to the necessity of finding sustainable alternatives. Although the use of renewable sources limits the available chemical space for a “Green” production, the great variety of naturally occurring precursors, i.e., fatty acids and sugars, opens a myriad of possibilities to create biosurfactants capable of replacing the fatigued fossil-derived amphiphiles. Here, we visit the concept of isomer-directed assembly applied to sugar-based surfactants, wherein amphiphile assembly and function are fine-tuned through changes in the stereochemical and regiochemical configuration of the molecule. As such, we show how isomerism defines directional interactions and solvation, ultimately dictating the assembly of surfactants. However, a general framework to understand the structure-function relationship for these is still missing, which is key to realizing this divergent set of tools for the design of new surfactants

The high potential of food waste (FW) as a substrate in the anaerobic digestion (AD) raises the dilemma between producing added value bioproducts such as volatile fatty acids (VFA) or biomethane. This work assessed the scale-up of producing VFA from FW. At lab-scale (5 L), pH 7 and organic loading rate (OLR) of 10 g COD/L/d were selected as the best conditions, obtaining a VFA yield of 36.6 % g COD-VFA/g COD substrate and a rate of 3.9 g COD-VFA/L/d. Afterwards, a semi-industrial pilot plant (1.5 m3) was operated under these conditions, showing VFA production indicators in line with those of lab scale, with acetic acid as main VFA (50 % mass basis), followed by propionic and butyric (20 % each). The economic comparative between the production of VFA and biomethane concluded that revenues from VFA production (22.9 €/t FW) are considerably higher than those from biomethane (11.7 €/t FW)

Although modern anaerobic sewage treatment systems and in particular the upflow anaerobic sludge blanket reactor (UASB) have demonstrated remarkable performance in tropical and subtropical regions, the effluent quality is generally not compatible with discharge standards in many countries, so post-treatment becomes necessary. In practice, the most widely applied post-treatment options are polishing ponds (PPs) and other aerobic treatment bioreactors. PPs are treatment units treating anaerobically pre-treated wastewater, which distinguishes them from conventional waste treatment ponds, wherein normally raw wastewater is treated. Anaerobic pre-treatment has a very profound influence on the configuration and operation of PPs, as will be shown in this chapter. Other aerobic post-treatments can be realized with conventional activated sludge systems, or more complex technological solutions including membrane bioreactors (MBRs) or trickling filters. The anaerobic–aerobic treatment has important advantages compared to the purely aerobic treatment: the volume and sludge production is much smaller, there is a possibility that the anaerobic–aerobic system operates with energetic self-sufficiency and the concentration of excess sludge is much higher facilitating its processing. An important problem of anaerobic–aerobic treatment is the difficulty of producing a final effluent with low nutrient concentration. Anaerobic sewage treatment reduces the content of biodegradable organic matter in the effluent, limiting in practice the removal of phosphorus to the use of chemical precipitation systems. For the case of nitrogen, the alternatives only go through new processes, which complement the poor capacity of conventional denitrification due to the limited concentration of biodegradable organic matter. This limits in practice, the nitrogen elimination capacity of activated sludge systems or trickling f ilters treating effluents from UASB reactors. A notable breakthrough could occur i

The significant increase in atmospheric CO2 concentration originated mainly from fossil fuels combustion has encouraged the development and improvement of CO2 separation operations to reduce emissions and control climate change and global warming. Therefore, this work is focused on the separation of CO2 from N2 in flue gas streams under post-combustion conditions by developing low-cost adsorbents. Six carbons were fabricated from biomass resources (olive stones and almond shells) to assess their influence on CO2 adsorption capacity: One carbonized and two KOH-activated carbons with carbon/KOH ratio of 1:2 and 1:4 (w/w) for each precursor. The carbons were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), elemental analysis, nitrogen and carbon dioxide adsorption–desorption analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) and point of zero charge determination. In addition, the equilibrium adsorption data of pure components for all adsorbents were measured at 0, 25 and 50 °C between 0 and 760 mmHg and CO2/N2 selectivity was determined. Activated carbons were found to have higher CO2 adsorption capacity but with a reduction in apparent selectivity. Dynamic binary adsorption simulations performed in a fixed-bed column demonstrated that the activated carbon produced from olive stones with a carbon/KOH ratio of 1:4 (w/w) can separate a mixture of 14 % CO2 and 86 % N2 at 25 and 50 °C with the highest selectivity, CO2 adsorption capacity, CO2 purity and N2 recovery factor. Reducing flow rate, the breakthrough time increased. Moreover, the breakthrough time was reduced by increasing the temperature from 25 to 50 °C owing to the exothermic nature of adsorption process.

The presence of valuable and hazardous metals in waste printed circuit boards, especially, motherboards, makes their recovery necessary as implies great economic and environmental advantages and develops urban mining processes. Hence, this research is focused on the selective leaching of Cu, Pb, and Sn as base metals using nitric acid and hydrochloric acid and Au, Ag, and Pd as precious metals using thiourea and sodium thiosulfate from waste motherboards’ PCBs in a sequential eco-friendly two-stage process. Previously, thiourea and sodium thiosulfate were used as leaching agents to investigate their applicability for the leaching of metals from PCBs in a single-stage process. Screening experimental design was applied to screen the variables affecting the leaching process in order to evaluate their impact on the recovery of metals and select the significant factors. The results demonstrated that base and precious metals can be leached appropriately in two consecutive stages compared to a single-stage process. Nitric acid was found to be a much more efficient agent to leach Cu and Pb in comparison with hydrochloric acid which was more suitable for the leaching of Sn. In the case of precious metals, higher amounts of Au were leached using thiourea, whereas sodium thiosulfate was able to leach more Pd. Roughly similar results were obtained for the leaching of Ag using these leaching agents. Nitric acid concentration, average particle size, temperature, and leaching time were found to be significant to maximize the leaching of Cu and Pb and minimize that for Au, Ag, and Pd in the first stage. Initial pH was the only variable influencing the second stage, in particular, Au leaching by thiourea

The number of studies on the solubilities of amino acids in pure ionic liquids is currently very scarce. Focusing on fundamental studies for the recovery of added-value compounds from fisheries and aquaculture discards, in this work the solubility of several amino acids in acetate ionic liquids and their mixtures with water were determined at temperatures ranging from 298.15 K to 328.15 K and atmospheric pressure. Sharing the acetate anion, solubilities were higher in the ionic liquid with 1-ethyl-3-methylimidazolium than with 1-hexyl-3-methylimidazolium cation. Increasing temperatures resulted in enhanced solubilisation. Solubilities in the ionic liquids ranked thus: Pro > OH-Pro > Lys·HCl > Ala > Gly > Cys, with an intermediate position of Arg (the amino acid most influenced by the hydrophobic environment and temperature). In the case of the mixtures with water, the ranking was Pro > Lys·HCl > Ala > Arg > OH-Pro > Gly > Cys. The van't Hoff equation adequately correlated experimental solubilities in the range of temperatures studied, and the process of dissolution was found endothermic and entropy-driven in all the cases. The ionic liquid 1-ethyl-3-methylimidazolium should be considered for the target application and the water content a design variable to analyse

The main challenge in wastewater treatment is changing the perception of wastewater as a waste product to be treated or disposed of, and instead seeing it as a source of energy and other valuable byproducts. This approach is in line with the basic principles of a circular economy, which replaces the ‘end-of-life’ concept with reducing, reusing, recycling, and recovering materials in production, distribution and consumption processes. The anaerobic treatment of wastewater aligns with these goals: energy, safe water and nutrients can all be recovered in the process. As a result, the anaerobic process could represent the best mainstream treatment option for domestic wastewater. The development of powerful technologies such as high-rate and membrane reactors is making anaerobic wastewater treatment more viable, especially in cold and moderate climate regions where the process is made more challenging due to the low process efficiency for dilute streams such as domestic wastewaters. Anaerobic Treatment of Domestic Wastewater: Present Status and Potentialities presents the current state of knowledge and future perspectives of the anaerobic process applied as a mainstream treatment method of domestic wastewater. 12 chapters cover engineering, microbiology, process monitoring and control, sustainability, life-cycle assessment, and techno-economic analysis. Topical areas of research, including the fate of microplastics and antibiotic resistance in the treatment line, are also discussed. This book provides all the necessary knowledge to analyse, evaluate, design, and implement anaerobic bioreactors for domestic wastewater treatment, making it essential reading for doctoral and master's students of water treatment subjects, and professionals or researchers in the water sector.

The livestock sector plays an essential role in anthropogenic greenhouse gas emissions, where fodder crop production has been largely identified as the main contributor to their environmental impact. This research evaluates the attributional environmental impacts of introducing food industry subproducts such as apple and olive pomaces to reduce the proportion of maize grain in the formulation of diets for fattening pigs, according to four alternatives, including the current diet with 69% maize. For this, the life cycle assessment (LCA) methodology has been used to determine the hotspots associated to these changes, considering a cradle-to-gate approach and two functional units: 1 kg of feed diet (FU1) and 1 kg of weight gain (FU2). Furthermore, the potential environmental consequences of using these subproducts for pig diet have also been considered with a consequential LCA methodology. The results show that the best diet was the one containing about 33% maize and 43% subproducts for all categories analysed. In addition, the allocation method used to assign subproduct loads, including mass, economic, and zero-burdens allocation, is crucial to validate the assumptions and recommendations for this strategy. The consequential LCA results suggest that this strategy could involve both positive and negative impacts (considered as environmental credits), depending on the substitutes for the avoided maize stover and the potential displaced bioproducts that could be obtained from these subproducts, mainly for bioenergy production

There is an urgent need to switch from fossil to bio-based fuels in the transport sector, particularly in shipping and aviation. The growth of the world's population has resulted in a significant impact on passenger transport, with a noticeable increase in greenhouse gas emissions, depletion of fossil resources and associated risks in all three pillars of sustainability. In this context, new policies, standards and targets have been developed to reduce this environmental damage, which is mainly caused by the use of fossil fuels. Therefore, the alternative of using biofuels seems to be the most appropriate solution, to the extent that important targets have been set and specific directives have been developed for the integration of biofuels in the maritime and aviation sectors. However, to demonstrate that switching to biofuels is indeed beneficial, it is necessary to evaluate new biofuel scenarios from a life-cycle perspective, with particular emphasis on analyses that provide information beyond the present, such as prospective life-cycle assessments. To this end, the focus of this review is on the current trends in the production of biofuels for the marine and aviation sectors, taking into account the main targets set, the existing regulations and directives on the subject, and an analysis of the type of technologies used for their production. It also addresses biofuel Life Cycle Assessment (LCA) scenarios and future LCA approaches, and how these analyses should be carried out to be effective. Finally, key policies, standards and certifications are analyzed. The trends and bottlenecks discussed in this review concerning the actual and future development of the biofuels sector could be used by policy makers and stakeholders to identify efforts that favor the integration of biofuels into the value chain. Furthermore, it could be concluded that the evaluation of the guidelines foreseen in the development of competitive scenarios based on emerging technologies, as well

The transition towards a more environmentally friendly economy can be facilitated through the bioeconomy, which relies on the use of biological resources, processes and methods to provide goods and services. However, bio-based value chains are not inherently sustainable and require careful monitoring and assessment of their impacts across all dimensions of sustainability (environmental, economic and social). Quantifying and understanding these impacts require the use of robust frameworks and methodological approaches that are currently lacking, which could be considered a gap in achieving a more sustainable bioeconomy. In this context, the objective of this research report is to fill this gap by identifying and selecting the most appropriate environmental, social and economic indicators within the Life Cycle Assessment (LCA) methodology to ensure a comprehensive assessment of environmental and socio-economic constraints and an effective analysis of bio-based value chains at all stages of the life cycle, from raw material extraction to end-of-life management. A total of 17, 26 and 101 indicators were identified for the environmental, economic and social pillars, respectively. In addition, existing gaps were highlighted, and a future framework was outlined to refine and enrich the currently available indicators and the underlying methodology. The indicators provided constitute a building block for effectively exploring and assessing the sustainability of bio-based value chains by a wide range of stakeholders (e.g., policy makers, entrepreneurs, certification bodies) to facilitate informed decision-making, pave the way for balanced economic growth, improve social welfare and environmental protection, and overall promote more sustainable and resilient bio-based value chains.

This work focused on the drying of O/W emulsions employed to obtain templated structured oils with hydroxypropyl methylcellulose (HPMC) as oleogelator. Sunflower oil/water emulsions with different HPMC content (1%–3% w/w) were dried at different air temperatures (from 70 to 100 °C) employing two different initial thicknesses (0.25 and 0.50 cm). Drying kinetics showed the existence of an initial constant drying rate period followed by a falling drying rate period below critical moisture content. This critical content was constant (0.38 kg water/kg dry solid) independently of drying conditions and HPMC content. Drying rate decreased linearly with moisture content during the falling rate periods. A 3-parameter model was proposed to simulate drying kinetics in the range of drying temperature and HPMC content of tested oleogels. Physical properties of fresh and stored (20 days) oleogels such as oil binding capacity, color, and hardness were measured to evaluate drying conditions effect on product quality. Temperatures above 70 °C were necessary to promote the HPMC gelation. Best characteristics of oleogels in terms of texture, color and oil binding capacity were obtained with HPMC content of 2% w/w, 0.25 cm of emulsion thickness and 80 °C of drying temperature. These results are useful for the design of large-scale dryers for this new kind of products

Innovation in digitalization and low-carbon technologies are leading the way for the production sector. In the context of the bioeconomy, a path is opening up for the integration of bio-based processes into the value chain as alternative production schemes to fossil fuel-based production models, although process modeling and optimization is needed as this approach is at an early stage of design and development. The large number of variables in the biorefinery cascade scheme presents the inherent difficulty of the optimization strategy, considering conditions that allow for higher productivity and revenues in parallel with lower environmental burdens. The implementation of artificial intelligence (AI) through techniques such as machine learning and predictive modeling could be considered as an efficient tool for process optimization. Such techniques require large amounts of historical data to identify effects, synergies and clusters of parameters; detect production anomalies; develop models for predictive, prescriptive or root cause analysis; and provide autonomous control. In this sense, this critical review report aims to provide an overview of available reports that have considered AI for the evaluation of biorefinery production models, identifying its potentialities to enable better production strategies under the principles of sustainability and circular economy. This review aims to be useful for the development of further research on the implementation of digitalization of biorefinery processes. This work aims to identify the forefront innovations in the development of bio-based processes that meet efficiency and sustainability criteria in order to provide information of interest to policy makers, stakeholders and industry professionals

Biomass is one of the renewable resources with the greatest potential, not only because of the possibility of energy recovery but also because of its content in components of interest. In this context, the regions of Galicia and Portugal have large areas of land dedicated to forestry, agriculture and livestock, and the large amount of waste generated represents a cost for the producer. The importance of these facts has aroused great interest in society to focus its interest on improving the current situation while seeking a benefit, both environmental and economic, from existing resources. That is why the integration of biotechnological processes and biorefinery for their valorization are considered key aspects in the way of producing bioproducts and bioenergy. This research article proposes a process for producing resveratrol from whey from the dairy industry and eucalyptus residues from forestry exploitation. In order to evaluate its suitability, a techno-economic analysis and an environmental assessment have been carried out using the Life Cycle Assessment (LCA) methodology. The results obtained show the potential of these scenarios both from the economic point of view, by obtaining a minimum sale price of resveratrol to ensure the viability of the process below the market average, and from the environmental point of view, being eucalyptus residues those that result in a lower contribution to the environment per unit of resveratrol produced. Future research should focus on increasing the throughput of the production process to increase its profitability and on reducing energy requirements throughout the process, as these have been the main critical points identified. In addition, following the sensitivity assessment, it has been concluded that opting for renewable energy is the most sustainable option.

Moving from the linear production model to the circular economy approach is the main concern of the EU Circular Economy Action Plan. Population growth coupled with high demand for goods has led to a significant increase in solid waste, especially food waste, triggering the depletion of natural resources and the environmental burdens associated to their disposal. However, their physical, chemical and biological characteristics make them by-products with a high potential to be valorized and therefore used as resources for other industrial production models. This is the case of spent coffee grounds (SCGs), which are produced in large quantities on a daily basis. Therefore, valorization models under the approach of the biorefinery concept can be envisaged with the aims of recovering potential bioactive compounds and renewable energy. This has been the approach developed in this critical review, in which SCG recovery alternatives have been studied to obtain lignin, lipids, biofuels and phenolic compounds. In addition, a critical analysis of the outcomes of techno-economic and environmental evaluations available in the literature is included, in order to identify those indicators that provide information on the feasibility of their valorization.

Due to the CO2 emissions and greenhouse effect, reducing its harmful impacts on climatic conditions is necessary. CO2 adsorption in a microporous carbon structure is one of the more effective separation techniques to avoid this type of emissions. In this work, one biochar (BC) and five activated carbons (ACs) were produced from Pinus radiata sawdust by chemical activation with potassium hydroxide (KOH) or zinc chloride (ZnCl2). Characterization was performed by scanning and transmission electron microscopy (SEM and TEM), surface area and pore size distribution by volumetric N2 and CO2 adsorption experiments using the Brunauer-Emmet-Teller (BET) and Barret-Joyner-Halenda (BJH) methods, respectively, X-ray diffraction (XRD), elemental analysis and X-ray photoelectron spectroscopy (XPS). The performance efficiency of the carbons was analyzed in terms of CO2 adsorption capacity at an absolute pressure range of 0–760 mmHg and at different temperatures (0, 25 and 50 ºC). The apparent and IAST selectivity of CO2 over N2 were determined and all carbons showed preferential sorption for CO2. Langmuir, Freundlich and Toth isotherms were employed to analyze pure CO2 and N2 adsorption data and the Toth isotherm gave the best fit. The carbon activated at 600ºC with KOH at a ratio of 1:4 w/w achieved the largest CO2 uptake (5.79 mmol/g at 0 °C and 750 mmHg) due to a combination between high microporosity (89 %) and surface area (2437 m2/g). This carbon also reached a relatively high selectivity

Energy transition has implications not only for economic growth and social welfare but also for the planet. It is therefore important to provide a framework of quantifying how this transition might affect these aspects from a triple perspective. In this regard, an in-depth and critical analysis of the available reports, policy frameworks and initiatives on energy transition, under the sustainable and circular perspectives, has been developed. This manuscript provides a “know-how” framework to assist in decision making and to assess the effectiveness, gaps and future actions to be developed for an effective energy transition. It presents a set of indicators to assess the sustainable and circular potential of emerging technologies and renewable energy production schemes, focusing on the environmental, social and economic pillars. It also highlights the policies and initiatives that should be implemented to facilitate this transition, as well as analyzing a comparison between European countries on how to improve energy renewability in those with low scores in the energy transition indexes. This study provides a critical analysis of the implications on energy transition over environmental, social and economic sustainability, as well as on circularity. It provides a preselection of the most appropriate indicators (both quantitative and qualitative) to effectively analyze the transition. The outcomes of this study can help stakeholders, citizens and policy makers on where to focus to improve efficiency, renewability and technology development for a sustainable and circular energy transition

USABLE Packaging project has developed an innovative value chain based on mixed microbial cultures using organic wastes as feedstock to produce prototypes of PHA-based items that were compared to their commercial counterparts, so the expected better environmental performance can be checked. To do so, a cradle-to-grave life cycle assessment was carried out. The system was modeled integrating all available knowledge, from pilot-scale data to process simulators, and following upscaling frameworks. PHA-based items outperform their commercial counterparts since they show environmental benefits thanks to the avoided electricity obtained in the cogeneration heat and power unit within the PHA production; however, these environmental benefits are very sensitive to the substituted electricity environmental burdens. The different levels of development and market implementation are seen as critical and therefore attention should be paid on how upscaling affects the results and interpretation of the LCA while serving as a guide for process and product development

One of the most promising alternatives to face the environmental deterioration and handling of waste is the development of biotechnological processes. In this context, the winemaking process of red grapes gives rise to waste streams whose properties are suitable for the biotechnological production of high-value-added products, such as resveratrol, a polyphenol with functional properties. In this research article, vine pruning residues, grape must and wine lees are valorized through precision fermentation, considering its modeling at a real production scale using the SuperPro Designer tool. Besides, economic and environmental assessments provided valuable information on the potential commercialization of the resveratrol based on the proposed valorization process. The results obtained show that the use of grape must residues to produce resveratrol is the most promising alternative from both the techno-economic and environmental perspectives. In conclusion, it could be stated that the bioproduction of resveratrol by precision fermentation using wine-related waste is both sustainable adequate and economically attractive

Pursuing new sources for food production in a context of demographic growth requires achieving a sustainable production model to face the current climate crisis. The biorefinery concept emerges as a technological scheme for the integral processing of renewable resources such as food waste obtained from the processing industry. This research aims to evaluate the potential environmental impacts of the valorisation route of chickpea peel to produce dietary fibre. Coupling process modelling with life cycle assessment approaches allows designing the potential biorefinery platform and identifying factors that may restrict its application in large-scale production. Global warming, particulate matter, eutrophication and ecotoxicity-related, fossil scarcity, among others, were the impact categories analysed with a cradle-to-gate approach. Results showed, for instance, that one kilogram of dietary fibre product emits 7.62 kg CO2 eq, 14.08 g PM2.5 and 4.37 g of P eq. Furthermore, alkaline digestion and bleaching were the most impactful stages in the categories analysed, due to the use of potassium hydroxide and sodium chlorite, respectively. This research contributes to rethink chickpea hulls from the food industry as a by-product towards high value-added products with applicability in the same industry.

Mussels cooking wastewater (MCW) and fish processing wastewater (FPW) were utilized as feedstocks for the production of polyhydroxyalkanoates (PHA) and triacylglycerides (TAG) at the laboratory scale. This study presents a comparison of the techno-economic and environmental performance of ten circular economy-based and innovative processes, in which PHA/TAG are produced using Mixed Microbial Cultures (MMC), with benchmark wastewater treatments for MCW and FPW. The innovative systems were modeled based on the upscaling of lab-scale data using mass balances, and a centralized downstream processing (DSP) plant was proposed for PHA/TAG extraction. This study is the first to conduct a techno-economic and environmental analysis of a system with a centralized DSP. Consequently, the most favorable operational options were selected based on the techno economic and environmental performance of the ten proposed scenarios. The techno economic evaluations demonstrate that treatment costs for MCW and FPW could be reduced by 10% and 40%, respectively, compared to the benchmark treatment. Furthermore, environmental impacts could be significantly reduced (e.g., 10–70% for global warming potential) compared to the baseline scenario by implementing a system expansion approach. Regarding the centralized DSP, the production cost of PHA from MCW falls within a competitive market threshold, ranging from 0.95 to 1.18 €/kg. However, the production costs of PHA and TAG from FPW (1.40–2.21 €/kg PHA and 0.51–0.69 €/kg TAG) are hindered by the lower biomass concentration achieved. Hence, this study demonstrates, for the first time, the potential feasibility of circular economy-based strategies for valorizing saline industrial wastewaters through a centralized DSP approach

The climate crisis calls for a shift from petrochemicals to bio-based products to reduce environmental consequences. Polylactic acid (PLA) is one of the most widely used biopolymers, due to its mechanical properties and renewable origin, to produce bio-based compostable plastic for food packaging. The objective of this study is to determine the environmental feasibility of a second-generation PLA production based on wheat straw; and the role of a chemical recycling plant on the environmental performance of a bioproduct at an early design stage. A holistic assessment was performed through the Life Cycle Assessment (LCA) methodology considering both attributional and consequential perspectives, through a cradle-to-grave approach. The attributional LCA results show that lactic acid production was the main contributor due to the wheat straw pre-treatment and downstream separation and purification (DSP) processes. The integration of a recycling plant leads to a significant reduction of burdens, ranging from 1.38 to 0.44 kg CO2eq in the Global Warming category. Furthermore, consequential LCA results shows that the increased demand for substitute products for activities such as feeding, fertilisation and energy generation and the indirect emissions from land use change related to the conversion of land for the cultivation of raw materials are relevant factors in the environmental effects associated with the possible implementation of straw-based bioPLA production system

Nitrite-driven anaerobic methane oxidation (N-damo) is a promising biological process to achieve carbon–neutral wastewater treatment solutions, aligned with the sustainable development goals. Here, the enzymatic activities in a membrane bioreactor highly enriched in N-damo bacteria operated at high nitrogen removal rates were investigated. Metaproteomic analyses, with a special focus on metalloenzymes, revealed the complete enzymatic route of N-damo including their unique nitric oxide dismutases. The relative protein abundance evidenced that “Ca. Methylomirabilis lanthanidiphila” was the predominant N-damo species, attributed to the induction of its lanthanide-binding methanol dehydrogenase in the presence of cerium. Metaproteomics also disclosed the activity of the accompanying taxa in denitrification, methylotrophy and methanotrophy. The most abundant functional metalloenzymes from this community require copper, iron, and cerium as cofactors which was correlated with the metal consumptions in the bioreactor. This study highlights the usefulness of metaproteomics for evaluating the enzymatic activities in engineering systems to optimize microbial management

Utilities produce and store vast amount of data related to urban wastewater management. Not yet fully exploited, proper data analysis would provide relevant process information and represents a great opportunity to improve the process performance. In the last years, several statistical tools and benchmarking methods that can extract useful information from data have been described to analyse wastewater treatment plant (WWTP) energy efficiency. Improving energy efficiency at WWTPs is however a complex task which involves several actors (both internal and external to the water utility), requires an exchange of different types of information which can be analysed by a broad selection of methods. Benchmarking method therefore must not only be selected based on whether they provide a clear identification of inefficient processes; it must also match the available data and the skills of those performing the assessment and objectives of stakeholders interpreting the results. Here, we have identified the requirements of the most common benchmarking methods in terms of data, resources, complexity of use, and information provided. To do that, inefficiency is decomposed so that the analyst, considering the objective of the study and the available data, can link each element to the appropriate method for quantification and benchmarking, and relate inefficiency components with root-causes in wastewater treatment. Finally, a framework for selecting the most suitable benchmarking method to improve energy efficiency in WWTPs is proposed to assist water sector stakeholders. By offering guidelines on how integrates and links data, methods and actors in the water sector, the outcomes of this article are expected to move WWTPs towards increasing energy efficiency

Meat and its by-products offer a rich source of bioactive compounds which have potential applications in both the food and pharmaceutical industries. In this review, we present several extraction methods and report the identification and properties of bioactive peptides. We also examine the challenges and limitations associated with their use in food applications. Enzymatic hydrolysis and fermentation using starts cultures are common methods for generating bioactive peptides from meat proteins. Additionally, natural gastrointestinal digestion can also produce bioactive peptides. However, emerging technologies like high hydrostatic pressure, subcritical extraction and pulsed electric fields can improve hydrolysis and increase the yield of bioactive peptides. Online bioinformatics applications have emerged as an established method for identifying potentially bioactive peptides. These tools reduce the cost and time required for traditional methods of research. Finally, incorporating bioactive peptides into diets for specific purposes such as supporting vulnerable populations like children and the elderly ensures safety and efficacy

El objetivo general de este trabajo es modelar la adsorción de hidrógeno en sólidos carbonosos microporosos utilizando un enfoque basado en la termodinámica, aplicándolo a fluidos puros y mezclas binarias

Este traballo céntrase naqueles biopolímeros plásticos non xestionados tras a súa fase de uso, e en particular ao efecto que ten a radiación UV sobre eles. Mediante o deseño previo da experimentación oportuna acadáronse datos e información extrapolables á realidade sobre o comportamento destes no medio. Dita información é necesaria para poder avaliar a sustentabilidade ambiental dos biopolímeros plásticos baixo unha perspectiva de ciclo de vida completa, é dicir, incluíndo tamén o seu fin de vida a través de metodoloxías como a Análise de Ciclo de Vida (ACV)

The presence of organic micropollutants in water bodies represents a threat to living organisms and ecosystems due to their toxicological effects and recalcitrance in conventional wastewater treatments. In this context, the application of heterogeneous photo-Fenton based on magnetite nanoparticles supported on mesoporous silica (SBA15) is proposed to carry out the non-specific degradation of the model compounds ibuprofen, carbamazepine, hormones, bisphenol A and the dye ProcionRed®. The operating conditions (i.e., pH, catalyst load and hydrogen peroxide concentration) were optimized by Response Surface Methodology (RSM). The paramagnetic properties of the nanocatalysts allowed their repeated use in sequential batch operations with catalyst losses below 1%. The feasibility of the process was demonstrated as removal rates above 90% after twelve accomplished after twelve consecutive cycles. In addition, the contributions of different reactive oxygen species, mainly •OH, were analyzed together with the formation of by-products, achieving total mineralization values of 15% on average

In recent years, novel food is becoming an emerging trend increasingly more demanding in developed countries. Food proteins from vegetables (pulses, legumes, cereals), fungi, bacteria and insects are being researched to introduce them in meat alternatives, beverages, baked products and others. One of the most complex challenges for introducing novel foods on the market is to ensure food safety. New alimentary scenarios drive the detection of novel allergens that need to be identified and quantified with the aim of appropriate labelling. Allergenic reactions are mostly caused by proteins of great abundance in foods, most frequently of small molecular mass, glycosylated, watersoluble and with high stability to proteolysis. The most relevant plant and animal food allergens, such as lipid transfer proteins, profilins, seed storage proteins, lactoglobulins, caseins, tropomyosins and parvalbumins from fruits, vegetables, nuts, milk, eggs, shellfish and fish, have been investigated. New methods for massive screening in search of potential allergens must be developed, particularly concerning protein databases and other online tools. Moreover, several bioinformatic tools based on sequence alignment, motif identification or 3-D structure predictions should be implemented as well. Finally, targeted proteomics will become a powerful technology for the quantification of these hazardous proteins. The ultimate objective is to build an effective and resilient surveillance network with this cutting-edge technology.

Despite being toxic to some microbes in wastewater treatment, sulfide can also promote nitrogen removal through sulfide-oxidizing bacteria. This study evaluates the dissolved sulfide impact on a hybrid MBR treating the effluent of a mainstream UASB. A UASB-MBR (176 L) was fed with synthetic domestic sewage and operated for 154 days. Two periods were distinguished, one without (Period I) and one with (Period II) sulfide dissolved in the UASB effluent. Dissolved methane, COD, nitrogen, and organic micropollutants (OMP)s removals accomplished in the MBR during both periods were compared. Initially, sulfide inhibited methane removal, but once fully oxidized into sulfate in the anoxic compartment, the efficiencies recovered to similar levels as without sulfide (>70%). Sulfide additions significantly enhanced the MBR denitrification potential through sulfide-oxidizing bacteria, with improved removals in Period II (63.4 TN Lfeed−1) compared to Period I (40 mg TN Lfeed−1). Most of the nitrogen removal occurred in the anoxic compartment of the MBR, however, up to 21% of the nitrogen was denitrified in the aerobic compartment within the biofilm carriers. Aerobic methane oxidation coupled with denitrification, heterotrophic denitrifiers, sulfide oxidation, and anammox processes were involved in the nitrogen removal. COD and OMPs removals were not affected by sulfide

El presente pliego de condiciones constituye el conjunto de normas, instrucciones, especificaciones y disposiciones que serán de aplicación en la ejecución de la obra de la planta de producción de vainillina (4-hidroxi-3-metoxibenzaldehído) a partir de lignina Kraft en el Polígono de “A Reigosa”, Ponte Caldelas, provincia de Pontevedra. Se considerarán sujetas a las condiciones de este pliego todas las obras cuyas características, planos y presupuestos se encuentren adjuntas en las partes correspondientes del presente proyecto y las obras necesarias para la terminación de todas ellas

The depletion of fossil resources and the climate change crisis call for an urgent shift to production pathways based on renewable and low-carbon sources. In addition, plastic pollution worldwide motivates the identification of new sources for their bio-based counterparts, which have an increasing demand. This research aims to evaluate the environmental feasibility of different cereal-based feedstocks for the production of poly(butylene succinate) (PBS), which is obtained from the polymerisation of succinic acid (SA) and 1,4 butanediol (BDO) monomers. The baseline scenario analysed corresponds to the use of wheat straw as a source of the fermentable sugars. Furthermore, five other cereal-based production routes combining first-generation (1G) feedstocks such as wheat and maize grain, and second-generation (2G) feedstocks, such as sorghum, barley straw, and maize stover, combined with wheat straw, were evaluated. The Life Cycle Assessment (LCA) methodology was used to identify the main hotspots of these valorisation routes at the early stage of the biorefinery design, considering all the burden categories provided by the ReCiPe impact method. The results showed that the straw-based PBS profile reached a Global Warming Potential of 3.43 kg CO2eq, whereas a range value from 2.34 to 7.27 kg CO2eq was estimated when wheat straw is combined with sorghum and barley straw, respectively. The pre-treatment stage represents a substantial impact on the strategy considered to produce fermentable sugars, particularly, for barley straw. Therefore, improvements are still required to reduce the energy demand and increase the sugar yield

In this work, the novel N-damo (Nitrite dependent anaerobic methane oxidation) process was investigated at high biomass activities for its potential to remove simultaneously nitrite and methane, as well as selected antibiotics commonly found in sewage in trace amounts. For this purpose, two MBRs were operated at three high nitrite loading rates (NLRs), namely 76 ± 9.9, 161.5 ± 11.4 and 215.2 ± 24.2 mg N–NO⁻2 L−1 d−1, at long-term operation. The MBRs performance achieved a significantly high nitrite removal activity for an N-damo process (specific denitrifying activity of up to 540 mg N–NO⁻2 g−1 VSS d−1), even comparable to heterotrophic denitrification values. In this study, we have implemented a novel operational strategy that sets our work apart from previous studies with similar bioreactors. Specifically, we have introduced Cerium as a trace element in the feeding medium, which serves as a key differentiating factor. It allowed maintaining a stable reactor operation at high NLRs. Microbial community composition evidenced that both MBRs were dominated with N-damo bacteria (67–87% relative abundance in period III and I, respectively). However, a decrease in functional N-damo bacteria (Candidatus Methylomirabilis) abundance was observed during the increase in biomass activity and concentration, concomitantly with an increase of the other minor families (Hypomicrobiaceae and Xanthobacteraceae). Most of the selected antibiotics showed high biotransformation such as sulfamethoxazole, trimethoprim, cefalexin and azithromycin, whereas others such as roxithromycin and clarithromycin were only partially degraded (20–35%). On the contrary, ciprofloxacin showed almost no removal. Despite the metabolic enhancement, no apparent increase on the antibiotic removal was observed throughout the operation, suggesting that microbiological composition was of greater influence than its primary metabolic activity on the removal of antibiotics

Clostridium luticellarii is a recently discovered acetogen that is uniquely capable of producing butyric and isobutyric acid from various substrates (e.g. methanol), but it is unclear which factors influence its (iso)butyric acid production from H2 and CO2. We aimed to investigate the autotrophic metabolism of C. luticellarii by identifying the necessary growth conditions and examining the effects of pH and metabolite levels on product titers and selectivity. Results show that autotrophic growth of C. luticellarii requires the addition of complex nutrient sources and the absence of shaking conditions. Further experiments combined with thermodynamic calculations identified pH as a key parameter governing the direction of metabolic fluxes. At circumneutral pH (~6.5), acetic acid is the sole metabolic end product but C. luticellarii possesses the unique ability to co-oxidize organic acids such as valeric acid under high H2 partial pressures (>1 bar). Conversely, mildly acidic pH (≤5.5) stimulates the production of butyric and isobutyric acid while partly halting the oxidation of organic acids. Additionally, elevated acetic acid concentrations stimulated butyric and isobutyric acid production up to a combined selectivity of 53 ± 3%. Finally, our results suggest that isobutyric acid is produced by a reversible isomerization of butyric acid, but valeric and caproic acid are not isomerized. These combined insights can inform future efforts to optimize and scale-up the production of valuable chemicals from CO2 using C. luticellarii

Advanced oxidation processes such as Fenton reaction-based processes have attracted great interest in recent years as a promising alternative for the removal of persistent pollutants in wastewater. The use of nanocatalysts in advanced oxidation processes overcomes the limitations of homogeneous Fenton processes, where acidic pH values are required, and a large amount of sludge is generated after treatment. Aiming at maximizing the catalytic potential of the process, different configurations include coupling photocatalysis or electrochemistry to Fenton reactions. This manuscript presents a comparative environmental and economic analysis of different heterogeneous Fenton-based process using magnetic nanoparticles: Fenton, photo-Fenton, electro-Fenton and photoelectron-Fenton. These alternatives encompass not only different reaction conditions but also varying degradation kinetics, which control the treatment capability in each specific case. It is not only important to determine the technological feasibility of the proposal based on the removal performance of the target compounds, but also to identify the environmental profile of each configuration. In this regard, the Life Cycle Assessment methodology was applied considering a combination of primary and secondary data from process modeling. Moreover, and aiming towards the future large-scale implementation of the technology, an economic analysis of each configuration was also performed to provide a better understanding about the costs associated to the operation of Fenton-based wastewater treatments

The porcine liver could be used for the extraction of zinc-protoporphyrin (ZnPP) as a natural red meat pigment. During the autolysis process, porcine liver homogenates was incubated at pH 4.8 and 45 °C under anaerobic conditions to obtain insoluble ZnPP. After incubation, the homogenates were readjusted at pH 4.8, and at pH 7.5 before being centrifuged at 5500 × g for 20 min at 4 °C and the resulting supernatant were compared with the obtained at pH 4.8 at the beginning of the incubation. The molecular weight distributions of the porcine liver fractions at both pHs were very similar, however, eight essential amino acids were more abundant in fractions obtained at pH 4.8. Regarding the ORAC assay, porcine liver protein fraction at pH 4.8 showed the highest antioxidant capacity but antihypertensive inhibition was similar for both pHs. Peptides with strong bioactivity potential from aldehyde dehydrogenase, lactoylglutathione lyase, SEC14-like protein 3 and others were identified. The findings have demonstrated the potential of the porcine liver to extract natural pigments and bioactive peptides

Wheat plays an essential role in safeguarding global food security. However, its intensive agricultural production, aimed at maximizing crop yields and associated economic benefits, jeopardizes many ecosystem services and the economic stability of farmers. Rotations with leguminous are recognized as a promising strategy in favor of sustainable agriculture. However, not all crop rotations are suitable for promoting sustainability and their implications on agricultural soil and crop quality should be carefully analyzed. This research aims to demonstrate the environmental and economic benefits of introducing chickpea into a wheat-based system under Mediterranean pedo-climatic conditions. For this purpose, the crop rotation “wheat-chickpea” was evaluated and compared with the conventional regime (wheat monoculture) by means of life cycle assessment methodology. For this purpose, inventory data (e.g., agrochemical doses, machinery, energy consumption, production yield, among others) was compiled for each crop and cropping system, thus converted into environmental impacts based on two functional units: 1 ha per year and one € of gross margin. Eleven environmental indicators were analyzed, including soil quality and biodiversity loss. Results indicate that chickpea-wheat rotation system offers lower environmental impacts, regardless of the functional unit considered. Global warming (18 %) and freshwater ecotoxicity (20 %) were the categories with the largest reductions. Furthermore, a remarkable increase (96 %) in gross margin was observed with the rotation system, due to the low cost of chickpea cultivation and its higher market price. Nevertheless, proper fertilizer management remains essential to fully attain the environmental benefits of crop rotation with legumes

In this work, the possibility of using un-treated pine (Pinus radiata) sawdust as biosorbent for the removal of three wood dyes (blue, red and black) from aqueous solutions was investigated. The BET surface area of the material was 1.55 ± 0.81 m2 g−1 using N2 at − 196 °C and 17.83 ± 0.032 m2 g−1 using CO2 at 0 °C. The point of zero charge was 4.8. In addition, the material was characterized before and after adsorption by surface analytical techniques. Assays were performed to analize the stability of wood dyes with time and pH and also to estimate the pKa values. Batch adsorption experiments were performed and the influence of experimental parameters such as contact time (up to equilibrium), stirring rate (100 and 210 rpm), adsorbent dose (2–10 g L−1), pH (2–9) and initial dye concentration (5 and 300 mg L−1) were studied. The optimum conditions were pH 2 and adsorbent dose of 6 g L−1 and the highest adsorption percentages achieved at 5 mg L−1 were: 100.0% for the blue, 99.7% for the black and 92.4% for the red. For 300 mg L−1 adsorption efficiency decreased to 85.6, 57.0 and 63.8% for the blue, black and red ones, respectively. Kinetic data were best fitted to the pseudo-second order model, suggesting a chemisorption process. Freundlich and Dubidin-Radushkevich were the best isotherm models. Regeneration study showed that un-treated pine sawdust could be reused efficiently for red dye removal at least in up to four repeated adsorption–desorption cycles using NaOH as desorption agent

Soil plays an essential role as a habitat, source of nutrients and support for vegetation. Promoting food security and environmental sustainability of agricultural systems requires an integrated approach to soil fertility management. Agricultural activities should be developed with preventive approaches aimed at avoiding or reducing negative impacts on the soil physicochemical and biological properties and the depletion of soil nutrient reserves. In this regard, Egypt has developed the Sustainable Agricultural Development Strategy to encourage environmentally friendly practices among farmers, such as crop rotation and water management, in addition to extending agriculture to desert areas, favoring the socio-economic development of the region. In order to evaluate the outcomes of the plan beyond quantitative data of production, yield, consumption and emissions, the environmental profile of agriculture in Egypt has been assessed under a life-cycle perspective in order to identify the associated environmental burdens and ultimately contribute to improving the sustainability policies of agricultural activity within the framework of a crop rotation system. In particular, a two-year crop rotation (Egyptian clover-maize-wheat) was analyzed in two distinct agricultural areas in Egypt: New Lands in desert regions and Old Lands along the Nile River, traditionally recognized as fertile areas due to the river alluvium and water availability. The New Lands had the worst environmental profile for all impact categories, except for Soil organic carbon deficit and Global potential species loss. Irrigation and on-field emissions associated with mineral fertilization were identified as the most critical hotspots of Egyptian agriculture. In addition, land occupation and land transformation were reported as the main drivers of biodiversity loss and soil degradation, respectively. Beyond these results, further research on biodiversity and soil quality indicators is needed to more accurat

Wastewater containing dyes are released into water bodies generating serious problems in human health and marine life. To contribute to the solution of this problem, a novel activated carbon was prepared from untreated pine (Pinus radiata) sawdust by dry chemical activation with ZnCl2 and was used for wood dye adsorption. The carbon was characterized by point of zero charge, N2 and CO2 adsorption isotherms, SEM-EDX, and FTIR. N2 and CO2 surface areas were 471.4 and 319.5 m2 g−1, respectively, with 91% of micropores. Wood dye adsorption was studied in function of pH (2–12), adsorbent dose (0.1–4 g L−1), time (up to 48 h for blue and red and 12 h for black), and initial concentration (5–500 mg L−1). The equilibrium data for the blue and black dyes were satisfactorily fitted to the Freundlich model while those for the red dye to the Langmuir model. Kinetic data were explained by the pseudo-second order (chemisorption process) and intraparticle diffusion models. At 5 mg L−1, a 100% removal efficiency was achieved at all pH for the blue dye, whereas for the red and black, natural pH (5.1) and pH = 2, respectively, led to the best removal efficiencies, 96 and 56%. Increasing concentration above 25 mg L−1 significantly reduced adsorption efficiency for blue and red dyes. For the black dye increasing the dose to 1 g L−1, the adsorption efficiency reached 82% at 25 mg L−1. High removal efficiencies were achieved for all dyes at 25 mg L−1 and 4 g L−1

Unspecific peroxygenase (UPO) presents a wide range of biotechnological applications. This study targets the use of by-products from bioethanol synthesis to produce UPO by Agrocybe aegerita. Solid-state and submerged fermentations (SSF and SmF) were evaluated, achieving the highest titers of UPO and laccase in SmF using vinasse as nutrients source. Optimized UPO production of 331 U/L was achieved in 50% (v:v) vinasse with an inoculum grown for 14 days. These conditions were scaled-up to a 4 L reactor, achieving a UPO activity of 265 U/L. Fungal proteome expression was analyzed before and after UPO activity appeared by shotgun mass spectrometry proteomics. Laccase, dye-decolorizing peroxidases (DyP), lectins and proteins involved in reactive oxygen species (ROS) production and control were detected (in addition to UPO). Interestingly, the metabolism of complex sugars and nitrogen sources had a different activity at the beginning and end of the submerged fermentation

Apple pomace (AP) is a lignocellulosic residue from the juice and cider industries that can be valorized in a multi-product biorefinery to generate multiple value-added compounds, including biofuels such as butanol. Butanol is produced biologically by acetone-butanol-ethanol (ABE) fermentation using bacteria of the genus Clostridium from sugar-based feedstocks. In this study, AP hydrolysate was used as a substrate for producing butanol by ABE fermentation. Various environmental factors influence the amount of butanol produced, but only under certain conditions the so-called 'acid crash', an undesirable phenomenon characterized by a total arrest of cell growth and solvent production, can be avoided. Operational parameters that may influence the prevention of acid crash occurrence, such as pH, CaCO3 concentration and culture temperature, were optimized in C. beijerinckii CECT 508 cultures applying a Box-Behnken experimental design. The mathematical model of the fermentation found the optimal conditions of pH 7, 6.8 g/L of CaCO3 and 30 °C, and this was validated in an independent experiment carried out at the optimal conditions, reaching 10.75 g/L of butanol. Also, the comparison of butanol production between the supernatant of the AP hydrolysate (10.57 g/L) and the full hydrolysate with solids (11.69 g/L) indicated that it is possible to eliminate the centrifugation step after hydrolysis, which may allow to reduce process costs and the full utilization of apple pomace, aiming a zero-waste approach

The production of volatile fatty acids (VFA) is gaining momentum due to their central role in the emerging carboxylate platform. Particularly, the production of the longest VFA (from butyrate to caproate) is desired due to their increased economic value and easier downstream processing. While the use of undefined microbial cultures is usually preferred with organic waste streams, the use of defined microbial co-culture processes could tackle some of their drawbacks such as poor control over the process outcome, which often leads to low selectivity for the desired products. However, the extensive experimentation needed to design a co-culture system hinders the use of this technology. In this work, a workflow based on the combined use of mathematical models and wet experimentation is proposed to accelerate the design of novel bioprocesses. In particular, a co-culture consisting of Pediococcus pentosaceus and Megaphaera cerevisiae is used to target the production of high-value odd- and even‑carbon VFA. An unstructured kinetic model was developed, calibrated and used to design experiments with the goal of increasing the selectivity for the desired VFA, which were experimentally validated. In the case of even‑carbon VFA, the experimental validation showed an increase of 38 % in caproate yield and, in the case of enhanced odd‑carbon VFA experiments, the yield of butyrate and caproate diminished by 62 % and 94 %, respectively, while propionate became one of the main end products and valerate yield value increased from 0.007 to 0.085 gvalearte per gconsumed sugar. The workflow followed in this work proved to be a sound tool for bioprocess design due to its capacity to explore and design new experiments in silico in a fast way and ability to quickly adapt to new scenarios

The study compares the potential to produce volatile fatty acids (VFA) from sewage sludge, both raw and thermally pre-treated in two modes of operation. In batch mode, raw sludge at pH 8 obtained the highest maximum VFA yield (0.41 g COD-VFA/g CODfed) whereas pre-treated sludge achieved a lower value (0.27 g COD-VFA/g CODfed). The operation of 5-L continuous reactors showed that thermal hydrolysis pre-treatment (THP) did not have any significant influence on VFA yields, averaging 15.1 % g COD-VFA/g COD with raw sludge and 16.6 % g COD-VFA/g COD with pre-treated one. Microbial community analysis showed that phylum Firmicutes was predominant in both reactors and that the enzymatic profiles involved in VFA production were very similar regardless of the substrate fed

Looking for renewable energy sources is one of the main targets in the transition to low-carbon economies. Bioenergy appears as an alternative with great potential, but firstly, it requires addressing all aspects that can limit its environmental viability. Stillage has been identified as an environmental concern of the bioethanol production. Thus, eco-friendly strategies for valorizing this resource should be pursued. In this work, three strategies such as composting (non-energy valorization), one-stage anaerobic digestion (with the aim of biogas production), and dark fermentation followed by anaerobic digestion (scheme under development to produce biohydrogen and biogas) were evaluated under a life-cycle perspective; and through process modeling based on literature data. The aim is to identify the advantages and disadvantages of dark fermentation for the management of apple stillage. To do this, a cradle-to-gate and attributional framework were followed, considering impact and damage perspectives. Results showed a very significant environmental load (around 99%) of composting compared to the selected energy recovery schemes, considering the added value of compost and the associated emissions versus those of biofuels. Otherwise, small differences were found between single-stage anaerobic digestion and dark fermentation (up to 16%), mainly, due to changes in chemical consumption and organic matter degradation efficiency

Two-stage partial nitritation (PN) and anammox (AMX) systems showed promising results for applying autotrophic nitrogen removal under mainstream conditions. In this study, a pilot-scale (600 L per reactor) two-stage PN/AMX system was installed in a municipal wastewater treatment plant (WWTP) provided with a high-rate activated sludge (HRAS) system for organic carbon removal. The PN/AMX system was operated without temperature control (ranging from 11 to 28 °C) and was subjected to the same variations in wastewater characteristics as the WWTP (22 to 63 mg NH4+- N/L). The developed strategy is simple, does not require the addition of chemicals and is characterised by short start-up periods. The PN process was established by applying a high hydraulic load and maintained by in situ accumulated free nitrous acid (FNA) of 0.015–0.2 mg HNO2-N/L. Based on pH value, a controlled aeration strategy was applied to achieve the target nitrite to ammonium ratio in the effluent (1.1 g NO2–-N/g NH4+-N) to feed the AMX reactor. Although NOB were not fully washed out from the system, nitrite accumulation remained (>99 %) stable with no evidence of NOB activity. In the AMX reactor, an overall nitrogen removal efficiency of 80 % was achieved. Regarding effluent quality, 12 ± 3 mg TN/L was obtained, but 5 mg NO3–-N/L was already in the HRAS effluent. The relative abundance of NOB showed a strong negative correlation with the FNA concentration, providing a good strategy for establishing PN under mainstream conditions

With the still huge dependence on crude oil, it is crucial to develop enhanced oil recovery techniques to improve reservoir production and lifespan. Carbonate reservoirs constitute over half the world's oil reserves, but they are challenging in terms of recovery due to their complex pore network, oil-wet or mixed-wet rocks, and harsh conditions of temperature and salinity. This work offers a significant contribution to the exploitation of these reservoirs. A new formulation, able to provide very low interfacial tension at high temperatures with reduced adsorption on carbonate rocks, was designed. A low-cost traditional alkyl benzene sulfonate (RECOLAS158) was mixed with the cationic surface active ionic liquid N,N-diethoxylated-N-tallow-N-ethylammonium ethylsulfate. A formulation containing 56.4 wt% RECOLAS158 was selected for its good performance in terms of phase behavior, injectability and interfacial tension at a wide range of temperatures and salinities. A very significant tertiary oil recovery (19.53% of the original oil in place) and low blend adsorption (0.086 mgblend/grock), demonstrated the promising performance of the formulation. The key mechanism associated to the improvement of oil recovery is interfacial tension reduction

The Sustainable Development Goals defined by the United Nations established a roadmap on the way to a sustainable society based on a circular economy in which the residual fractions of process streams emerge as raw materials for the provision of material goods and services. In this context, the approach of biorefineries as the technological scheme for processing integrally renewable resources stands out. Among the different target products, "bioactive" compounds have aroused great interest given their high added value. This work evaluates the environmental profile associated with the valorization of residual lignocellulosic waste streams: olive pruning and eucalyptus residues for the biotechnological production of nisin, an antimicrobial compound produced by Lactoccocus lactis with application in the food preservation and biomedical sectors. Process modelling in combination with Life Cycle Analysis allowed addressing the conceptual design and the environmental assessment of a full-scale production process. As a main conclusion, the technological feasibility of the valorization of waste fractions as sources of fermentable sugars in the biotechnological process has been demonstrated. Moreover, the integral use of the raw materials can allow not only the production of nisin as an economic driver, but also of other biotechnological products such as lactic acid and energy for the self-supply of the process. The main novelty of this manuscript is based on rethinking the valorization of lignocellulosic waste beyond energy recovery to obtain bioproducts with high added value in the market with applicability in the food sector. Although energy recovery is the most widely implemented end-of-life option, the use of lignocellulosic waste as fermentable sugars has been shown to improve sustainability and circularity outcomes