IPS - Artículos de revista https://uvadoc.uva.es/handle/10324/35295 2026-04-13T20:28:25Z 2026-04-13T20:28:25Z Salgado, Eva M. Rodríguez, Nerea Ángeles Torres, Roxana Gonçalves, Ana L. Ratola, Nuno Pires, José C.M. Cantera Ruiz De Pellon, Sara Lebrero Fernández, Raquel https://uvadoc.uva.es/handle/10324/84017 2026-04-13T19:02:27Z 2026-01-01T00:00:00Z

Volatile methylsiloxanes (VMS) are widely occurring biogas contaminants that hinder the performance and lifetime of energy recovery systems. Despite the feasibility of biological VMS removal, important limitations remain, and the use of microalgal-bacterial consortia has not yet been investigated. The present study presents the first assessment of the removal of seven VMS from simulated biogas using a multi-channel capillary pho- tobioreactor (PBR). Chlorella vulgaris was initially used as the sole inoculum, followed by the addition of mixed recirculation sludge, VMS-enriched sludge, and the surfactant Tween 80. C. vulgaris provided CO2 fixation rates up to 302 mgCO2 L 1 d 1 and average total VMS removal and elimination capacity of 36 ± 10% and 1142 ± 436 μg L 1 h 1, respectively. PBR re-inoculation with sludge did not significantly improve the average VMS removal due to gas-liquid mass transfer limitations. The addition of Tween 80 increased the total VMS removal efficiency and elimination capacity to 60 ± 4% and 2136 ± 195 μg L 1 h 1, respectively. This improvement was attributed to enhanced mass transfer of VMS such as D5 (decamethylcyclopentasiloxane) from the simulated biogas to the culture, along with a substantial increase in siloxane adsorption and accumulation in the biomass. The combi- nation of a microalgal-bacterial consortium with a capillary reactor was proved effective for VMS removal, namely in the presence of a surfactant. These findings open new perspectives for the integration of microalgae- based systems and advances PBR designs into biogas upgrading technologies, which are essential to enable the reliable large-scale use of biogas as a renewable energy source.

2026-01-01T00:00:00Z Molinos Senante, María Maziotis, Alexandros https://uvadoc.uva.es/handle/10324/83972 2026-04-09T19:01:16Z 2026-01-01T00:00:00Z

The transition towards a circular economy in the water industry has increased the strategic importance of bio- resources management, particularly in relation to renewable energy generation and sewage sludge treatment within wastewater services. Despite this relevance, techno-economic performance in bioresources activities has not been systematically assessed. To address this gap, this study introduces the Techno-Economic Bioresource Index (TEBI), a novel benchmarking indicator based on a non-radial Data Envelopment Analysis approach. The framework is applied to a sample of 50 observations operating in England and Wales. The results reveal sub- stantial heterogeneity in performance, with TEBI values ranging from 0.124 to 1.000 and an average score of 0.76, indicating an average improvement potential of approximately 24%. Inefficiencies are found to be variable- specific rather than systemic, with energy utilization, energy export, and untreated sludge emerging as the main sources of inefficiency for several utilities. No relationship is observed between techno-economic efficiency and utility size. A super-efficiency analysis further discriminates among efficient utilities, enabling the identification of robust benchmarks. The findings demonstrate that efficient bioresources management can play a key role in supporting the transition towards a circular water industry, and that TEBI provides a transparent and operational tool to support regulatory benchmarking and evidence-based decision-making.

2026-01-01T00:00:00Z Lacerda Dos Santos, Thalita Vargas Estrada, Laura Gabriela Blanco, Saul Ribeiro da Silva, Gustavo Henrique Muñoz Torre, Raúl https://uvadoc.uva.es/handle/10324/83962 2026-04-08T19:16:17Z 2026-01-01T00:00:00Z

The synergy between microalgae and bacteria in photobioreactors is complex, with the competition between assimilation and nitrification critically influencing nutrient removal efficiency. This study investigated the interplay between nutrient and carbon removal pathways in a single-stage microalgal-bacterial photobioreactor treating domestic wastewater by selectively inhibiting nitrification with allylthiourea (ATU). The inhibition successfully suppressed bacterial activity, reducing the NH4+ removal rate by 20% and increasing the contribution of microalgal assimilation to total nitrogen removal from 59% to 68%. Moreover, ATU addition induced a change in microbial population structure, as suggested by the decline in relative abundance of Proteobacteria and Bacteroidota phyla, which ultimately mediated a shift in the share of carbon fate mechanisms. The total organic carbon removal efficiency decreased from 94 ± 1% to 88 ± 1%, while the carbon assimilation efficiency into biomass was increased from 65% to 80%. Thus, mixotrophic microalgae like Scenedesmus sp. became the dominant genus, alongside the cyanobacterium Nodosilinea. Phosphate removal remained consistently high (97–98%) and unaffected by ATU addition, indicating its decoupling from nitrification. The results demonstrated that nitrogen removal was mainly dominated by microalgae assimilation complemented by bacterial pathway, consistent with nitrification-denitrification to achieve complete nitrogen removal.

2026-01-01T00:00:00Z López Linares, Juan Carlos Romero García, Juan Miguel Vidal, Alfonso M. Lucas Yagüe, Susana Coca Sanz, Mónica García Cubero, M.Teresa Romero, Inmaculada Castro, Eulogio https://uvadoc.uva.es/handle/10324/83921 2026-04-06T19:06:12Z 2026-01-01T00:00:00Z

Vine shoots, a carbohydrate-rich lignocellulosic residue, represent a promising feedstock for producing xylitol, butanol, and 2,3-butanediol (2,3-BDO) in an integrated biorefinery. In this work, dilute sulfuric acid steam explosion (190 ◦C, 5 min, 1.6% w/v H2SO4) was used for the pretreatment of vine shoots. Xylitol was subse- quently produced from the vine shoots hemicellulosic hydrolysate using C. boidinii and C. guilliermondii; while butanol and 2,3-BDO were generated from the remaining solid fraction of vine shoots using C. beijerinckii and P. polymyxa, respectively. Furthermore, two process configurations for butanol and 2,3-BDO generation were evaluated: separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF), with comparisons conducted at high solids loadings (10% and 15% w/v). As a result, 8.4 g/L xylitol were achieved from the hemicellulosic fraction with C. boidinii. From the cellulosic fraction, the SHF configuration at the highest solids loading (15% w/v) yielded 8.8 g/L of butanol (corresponding to 12.4 g/L of total ABE) and 13.8 g/L of 2,3-BDO. Therefore, these results demonstrate the potential of vine shoots as a versatile feedstock for an integrated biorefinery

2026-01-01T00:00:00Z Maziotis, Alexandros Molinos Senante, María https://uvadoc.uva.es/handle/10324/83840 2026-03-26T20:05:24Z 2026-01-01T00:00:00Z

Wastewater treatment plants (WWTPs) play a critical role in protecting public health and the environment but are also contributors to carbon emissions. Improving the eco-efficiency of WWTPs is essential for advancing sustainability in the sector. This study proposes a parametric approach using stochastic frontier analysis to evaluate the eco-efficiency of 108 WWTPs in Spain and estimate the marginal cost of reducing GHG emissions. The eco-efficiency index (EcoEI) integrates operational costs, pollutant removal efficiency, and indirect carbon emissions. Results show an average EcoEI of 0.638, suggesting that WWTPs could improve performance by approximately 36%. The estimated marginal abatement cost of carbon emissions ranges from €0.010 to €1.240 per kg CO2eq, with an average of €0.309/kg CO2eq. Significant differences in marginal costs were found across secondary treatment technologies, though not in eco-efficiency scores. These findings have important implications for utilities and regulators aiming to enhance sustainability and meet the targets set by EU Directive 2024/3019.

2026-01-01T00:00:00Z Huang Lin, Elisa Cantera Ruiz De Pellon, Sara Lebrero Fernández, Raquel https://uvadoc.uva.es/handle/10324/83838 2026-03-26T20:05:21Z 2026-01-01T00:00:00Z

The production of high-value compounds such as ectoine in the pharmaceutical industry faces significant challenges, including high costs, resource intensity and reliance on refined sugars. This study presents a novel bioproduction platform converting carbon dioxide (CO2) and the industrial contaminant thiosulfate (S2O32-) into ectoine using the halophilic strain Guyparkeria halophila. To overcome limitations in biomass accumulation and incomplete S2O32- oxidation, cultivation and operational parameters, including S2O32- loading rate, pH, and dilution rate, were systematically optimized in continuous stirred tank reactors. A S2O32- loading rate of 5 g d-1 supported higher specific ectoine accumulation and promoted complete S2O32- oxidation, while a moderate pH increase up to 7.6 further improved CO2 assimilation. Additionally, implementing a prior semi-batch operation followed by a low dilution rate stage (0.10 d-1) effectively enhanced biomass and ectoine productivity. Under these optimized conditions, biomass accumulation increased significantly to 290.0 ± 20.2 mg L-1, with specific ectoine contents of 387.3 ± 23.1 mgEct gbiomass-1 and productivities of 10.6 ± 0.6 gEct m-3 d-1. This work demonstrated a scalable, efficient and sustainable platform for ectoine biosynthesis that integrates CO2 valorization and industrial by-product utilization, highlighting the potential of halophilic microbes for greener and economically viable pharmaceutical manufacturing.

2026-01-01T00:00:00Z Levío Raimán, Marcela Elisabeth Tomás Pejó, Elia González Fernández, María Cristina https://uvadoc.uva.es/handle/10324/83735 2026-03-23T09:28:59Z 2026-01-01T00:00:00Z

The present research describes the long-term fermentation of a microalgae-yeast consortium using volatile fatty acids (VFAs) supplied from a real anaerobic fermentation (AF) waste stream, enabling their efficient conversion into lipid and protein production. In addition, the macromolecular composition of the produced microbial biomass in terms of fatty acid (FAs) and amino acid (AAs) profiles highlighting its potential for diverse applications. The microbial consortium formulated by Chlorella vulgaris and Yarrowia lipolytica depicted a high lipid content of a 50.7 ± 2.5% w/w, followed by a 35.5 ± 1.1% w/w of proteins and 13.8 ± 2.0% w/w of carbohydrates. The lipids profile showed the predominance of even chain length acids (C16 and C18). In terms of AAs profile, glutamic acid was the most abundant (13.0 ± 0.1% w/w of volatile solids). This research does not only evidence long term operation feasibility but also provides an in-depth characterization of FAs and AAs profiles of this innovative microbial consortium. These data enable the rational matching of biomass-derived components with specific conversion pathways and end-use requirements, thereby maximizing their value and suitability for targeted bio-based industrial applications.

2026-01-01T00:00:00Z Vicente Martínez, Marta de Tomás Pejó, Elia González Fernández, María Cristina https://uvadoc.uva.es/handle/10324/83371 2026-03-09T20:08:32Z 2026-01-01T00:00:00Z

Microbial consortia play an essential role in anaerobic fermentation (AF) devoted to the production of short- chain fatty acids (SCFAs) from organic wastes. AF is usually performed by a conventional anaerobic micro- biome (CM) sourced from anaerobic digestion reactors. During AF, the microbiome undergoes an adaptation period to the imposed operational conditions and substrate characteristics, leading to the bio-enrichment of certain microorganisms. This work compared the use of CM and a bio-enriched microbiome (BM) as inoculum for AF of agricultural wastes in continuous stirred tank reactors (CSTR) with hydraulic retention time (HRT) of 8 d. The novelty of this study lies in demonstrating that using a BM enhances the production rate of SCFAs when compared to CM. BM, composed of adapted microorganisms previously working at an HRT of 10 d, allowed the highest SCFAs productivity (1.97 g/L⋅d) and concentration (15.6 g/L). Bioconversion efficiencies achieved with BM and CM (60.1 % and 71.8 %, respectively) were among the highest reported in literature. Microbiome analysis revealed inoculum-driven changes in the microbial community. However, Clostridium and Megasphaera, which are involved in the hydrolysis and acidification steps of AF and are associated with acetic acid formation and chain elongation, predominated in all cases (up to 48 % of the microbial abundance within the total com- munity). These results evidenced the feasibility of operating CSTRs at an HRT of 8 d with diverse inoculum sources to maintain exceptionally high SCFA productivity and bioconversion. The outcomes also highlighted the robustness of the microbial community, even under short HRT, providing a novel strategy for AF processes optimization.

2026-01-01T00:00:00Z Lozano Martín, Alberto González Galán, Alba Mei López Linares, Juan Carlos Coca Sanz, Mónica García Cubero, María Teresa Lucas Yagüe, Susana https://uvadoc.uva.es/handle/10324/83307 2026-03-25T12:08:48Z 2026-01-01T00:00:00Z

This study presents an integrated, solvent-free biorefinery approach that couples microwave-assisted extraction (MAE), ultrafiltration (UF), and separate enzymatic hydrolysis and fermentation (SHF) to co-produce pectin- derived oligosaccharides (POS), predominantly oligogalacturonides (OGalA), and 2,3-butanediol (2,3-BDO) from apple pomace (AP). Through response surface methodology, optimized MAE temperature and time conditions to maximize OGalA formation were identified, while also limiting sugar degradation. Under these conditions (136 ◦C, 8.1 min), the extract contained OGalA at 4.0 ± 0.2 g/L, corresponding to a recovery of 53.7 ± 0.8%, and a pectin yield of 22.3 ± 0.2% was achieved (dry AP basis). Subsequently, an ultrafiltration step using a 3 kDa membrane yielded an OGalA solution concentrated to 11.5 ± 0.1 g/L and partially depleted small molecules. Compositional profiling also confirmed a notable enrichment of the rest of the oligosaccharide fractions, with increases ranging from 2.4- to 3.2-fold. In parallel, the MAE-pretreated solid, selectively depleted in pectic do- mains and enriched in glucan (~37%), was saccharified and fermented via a sequential hydrolysis-fermentation scheme to produce 2,3-BDO. Fermentation trials with Bacillus strains achieved concentrations of 10.3 ± 0.4 g/L (B. amyloliquefaciens) and 9.5 ± 0.2 g/L within 47 h (B. licheniformis), with sugar clearance below 48 h at 10–15% (w/v) solids loading. In conclusion, an integrated MAE → UF → SHF configuration co-producing POS and 2,3-BDO offers a practical route to valorize AP and advance circular bioeconomy goals in fruit-processing regions.

2026-01-01T00:00:00Z León Vaz, Antonio Tejero Álvarez, Lucía García Encina, Pedro Antonio Muñoz Torre, Raúl Torres Franco, Andrés Felipe https://uvadoc.uva.es/handle/10324/82810 2026-02-17T20:02:42Z 2026-01-01T00:00:00Z

New viruses are one of the major health challenges that human society is facing during this century. One of the most promising solutions is searching for natural organisms or molecules with antiviral capacity, with emerging microalgae as a promising solution in recent years. Thus, in this work, the antiviral capacity of ten species of freshwater and marine microalgae was tested against three enveloped and non-enveloped bacteriophages (PhiX174, MS2 and Phi6), showing inhibition efficiencies ranging from 40 to 80% compared with control in- fections. Moreover, the PCA analysis revealed the influence of the microalgal cell wall on the different bacte- riophages’ inactivation capacity. Finally, the inactivation of the three bacteriophages in liquid cultures was studied using the microalgae Chlorella vulgaris and Thalassiosira weissflogii. These microalgae inactivated 99.999% of the MS2 and Phi6, and 99.9% of PhiX174 after 72 h of cultivation, respectively. Additionally, T90 values ranging from 7 to 12 h for PhiX174, 3 to 12 h for MS2 and 2.5 to 3 h for Phi6 were achieved by the two tested microalgae. These results highlight the potential of microalgae for the inactivation of viruses in waste- waters and as an outstanding source of antivirals.

2026-01-01T00:00:00Z Vargas Estrada, Laura Gabriela Muñoz Torre, Raúl https://uvadoc.uva.es/handle/10324/82680 2026-02-10T20:02:07Z 2026-01-01T00:00:00Z

The increasing demand for biomethane in Europe requires the urgent development of sustainable and cost-effective technologies to meet the ambitious target of producing 35 bcm of biomethane by 2030. Biological technologies stand as a promising integrating platform to purify biogas and valorize biogenic CO2, while producing high-value chemicals. Photosynthetic biogas upgrading has demonstrated to be an attractive platform as microalgae can fix CO2 while producing biomass that can be further valorized for biofuel, biofertilizer or biostimulant production. However, its high investment cost and the low microalgae biomass productivities have limited commercialization. Recently, the supplementation of nanoparticles obtained from olive-mill wastewater, has demonstrated to be a promising technique to improve biomass productivity, CO2 removals, and the overall stability of the system. This review summarizes the current trends and future outlooks of this sustainable platform aiming at the development of novel integrated microalgae biorefineries devoted to biogas upgrading and high-value compounds production.

2026-01-01T00:00:00Z Anagnostopoulou, Chrysa Vargas Estrada, Laura Gabriela Kougias, Panagiotis G. Muñoz Torre, Raúl https://uvadoc.uva.es/handle/10324/82594 2026-02-05T20:01:23Z 2026-01-01T00:00:00Z

Carbon-coated iron-based nanoparticles have demonstrated a significant potential to enhance the performance of biological processes, particularly microalgal cultivation. In this study, the effect of two types of commercially available iron-based nanoparticles, namely CALPECH and SMALLOPS, was evaluated on Arthrospira platensis metabolism during biogas upgrading in batch cultures. Both nanoparticles enhanced CO2 capture, O2 production, cyanobacterial growth and phycocyanin synthesis across all tested concentrations. However, the highest phycocyanin content (180 mg⋅g 1) was reached by the addition of CALPECH nanoparticles at 100 mg⋅L 1. Further experiments under stress conditions, including increased light intensity (300 and 600 μmol⋅m 2⋅s 1) and salinity (0.1–0.5 M NaCl) confirmed the beneficial effects of CALPECH. At 600 μmol⋅m 2⋅s 1 CALPECH nano- particles enhanced biomass productivity and increased CO2 capture by 33 % while maintaining phycocyanin content at 178 mg⋅g 1. Moreover, the addition of 100 mg⋅L 1 of CALPECH nanoparticles at 0.1 M NaCl slightly improved biogas upgrading performance and increased phycocyanin content to 192.7 mg⋅g 1. In this context, increasing salinity to 0.5 M caused stress in Arthrospira platensis cells, reducing photosynthetic efficiency regardless of nanoparticle addition. These outcomes highlight the potential of carbon-coated iron-based nano- particles to improve Arthrospira platensis growth and pigment production, which would ultimately increase the techno-economic feasibility of photosynthetic biogas upgrading

2026-01-01T00:00:00Z Díaz Moreno, Nicolás Lebrero Fernández, Raquel Cantera Ruiz De Pellon, Sara https://uvadoc.uva.es/handle/10324/82484 2026-02-03T20:01:33Z 2026-01-01T00:00:00Z

Toluene, which has been listed in the Pollutant Release and Transfer Register (PRTR) of many countries, is one of the most emitted pollutants to the atmosphere. This study demonstrates for the first time a new perspective in toluene treatment based on its continuous bioconversion into high-value chemicals, specifically ectoine and hydroxyectoine, which hold considerable commercial relevance in the cosmetic industry with market prices reaching 1000 € kg 1. Specific ectoine and hydroxyectoine contents of 27.3 mg gTSS 1 were achieved together with toluene elimination capacities of 7.2 ± 1.9 g m 3 h 1 and a maximum biomass concentration of 1.8 g L 1. Ectoine synthesis predominated initially, later shifting toward hydroxyectoine, reaching a combined amount of 71.2 mg L 1 (ectoine:hydroxyectoine 32:68) by the end of the assay. Metagenomic analysis revealed key path- ways and taxa involved in toluene degradation and ectoine and hydroxyectoine synthesis. Members of Paeni- bacillus, Rhodococcus and Microbacterium were identified as possessing the enzymes required for toluene degradation via the TOL pathway, while Gordonia, the most abundant genus, was primarily associated with the degradation of intermediates such as benzoate, muconate, or oxoadipate derivatives and their bioconversion into ectoine. These findings revealed a potential metabolically diverse consortium with functional complementarities, where metabolic synergies overcome species-specific limitations and promote the elimination and subsequent valorization of toluene into high-value products fostering sustainable industrial innovation.

2026-01-01T00:00:00Z Torres Franco, Andrés Felipe Herrero Lobo, Raquel Lebrero Fernández, Raquel Muñoz Torre, Raúl https://uvadoc.uva.es/handle/10324/81668 2026-01-16T20:02:00Z 2026-01-01T00:00:00Z

Ectoine is one of the most profitable value chains for biogas valorisation. This study assessed the long-term effects of biomilking for ectoine (Ect) and hydroxyectoine (Hy) extraction on upstream methane bioconversion into ectoines using a halotolerant methanotrophic consortium cultivated in a Taylor-Flow bioreactor. After a control stage (S-I), fractions of the culture broth volume of 10 %, 50 %, 30 % and 60 % (S-II to S-VI) were subjected to biomilking before a final control (S-VII). No adverse effects were observed at 10 %, while higher fractions led to salt depletion, a ~10 % reduction in CH4 bioconversion efficiency, and a loss of dominant ectoine producers, mainly Methylomicrobium. A decrease in intracellular Ect was also observed. Restoring salt levels (S- VI) recovered Methylomicrobium dominance and Ect content in the culture broth. Enhanced biomilking yielded up to 27.2 g-Ect + Hy per inlet kg of CH4, supporting its feasibility for sustainable biogas valorisation at a com- mercial scale.

2026-01-01T00:00:00Z Romano, Fabiana Zarra, Tiziano Palacio Martínez, Laura García Depraect, Octavio Muñoz Torre, Raúl https://uvadoc.uva.es/handle/10324/81665 2026-01-16T20:01:59Z 2026-01-01T00:00:00Z

The increasing interest in sustainable waste management has spurred the development of innovative technolo- gies for resource recovery. In this context, organic waste fermentation generates effluents rich in ammonium and volatile fatty acids (VFAs), both of which represent valuable precursors for the fertilizer and chemical industries. This study introduces and evaluates an innovative membrane-based methodology enabling the simultaneous recovery of ammonia (NH3) and VFAs from synthetic and real dark fermentation broths. The experimental setup employed a gas–liquid membrane contactor consisting of a 44 cm2 hydrophobic polytetrafluoroethylene (PTFE) membrane (0.22 μm pore size) housed in a flat-plate module. The effects of different extraction solutions (HCl, H2SO4, NaOH, and ionic liquids), their concentrations, and the flow rates of both the fermentation effluent (500 mL min 1) and the extracting solution (250 mL min 1) were systematically investigated, along with the influence of the broth pH (7.0 and 5.5). Among the tested conditions, 2 M NaOH was identified as the most effective extraction medium, achieving simultaneous recoveries of 24.5 % for NH3, 50 % for propionic, butyric, and valeric acids, and 42 % for acetic acid after 168 h of operation in an acidogenic broth at pH 5.5. Furthermore, higher solvent concentrations and increased recirculation velocities were positively correlated with improved NH3 and VFA recovery, regardless of the solvent type. Overall, the results highlight the potential of the proposed membrane contactor-based approach as a promising and scalable technology for integrated resource recovery from fermentation effluents

2026-01-01T00:00:00Z Santos Beneit, Fernando Bordel Velasco, Sergio Martín González, Diego Fuente Tagarro, Carlos de la García Depraect, Octavio Börner, Tim Börner, Rosa Aragão Muñoz Torre, Raúl https://uvadoc.uva.es/handle/10324/81658 2026-01-16T20:01:58Z 2026-01-01T00:00:00Z

Polyhydroxyalkanoates (PHAs) are promising biodegradable alternatives to petroleum-based plastics, yet their large-scale application remains hindered by high production costs. Here, a direct and cost-effective microbial strategy to upcycle polyester waste into PHAs using Paracoccus denitrificans was investigated. Remarkably, the bacterium metabolized 10 out of 12 tested plastic-derived monomers and efficiently accumulated intracellular PHAs, even when fed with pretreated mixed polyester waste instead of purified substrates. More than 80 % of polyester monomers supported growth, and medium optimization through nitrogen reduction boosted PHA content up to 30 % of cell dry weight. This one-step process circumvents costly separation steps, enabling the valorization of heterogeneous plastic mixtures and significantly reducing both economic and processing burdens. By transforming post-consumer plastics into high-value biopolymers, this work positions P. denitrificans as a versatile platform for circular bioeconomy strategies, directly supporting global sustainability agendas and advancing sustainable bioprocessing for the green industry

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