This review comprehensively examines the advancements and challenges in anaerobic digestion (AD) for biogas production, emphasising technological, microbial, and policy perspectives. It highlights the AD significant potential for valorising diverse organic substrates, including manure, food waste, and microalgae, thereby contributing to renewable energy generation and greenhouse gas mitigation. Key operational factors influencing biogas yield include substrate composition, temperature (preferably mesophilic conditions), pH (6.5–7.5), and the substrate-to-inoculum ratio (SIR), all of which significantly affect microbial activity and process stability. Co-digestion strategies and pretreatments are examined for their roles in enhancing biodegradability and methane yield, respectively. Microbial community dynamics, particularly responses to feedstock heterogeneity and operational parameters, are integral to process optimisation. Advances in metagenomics have provided insights into microbial resilience and adaptation to conditions such as high ammonium levels. This review also discusses various modelling approaches, including kinetic models and machine learning techniques, for predicting and optimising biogas production. Additionally, policy frameworks within regions such as the European Union and Brazil, along with economic incentives and regulatory hurdles, are also considered crucial for scaling up deployment. Challenges such as digestate management and high capital costs persist, underscoring the need for integrated strategies to enhance the sustainability and viability of AD-based biogas projects.

Pectinolytic enzymes are a group of enzymes widely used in the food industry. They can be obtained through a wide range of by-products and agricultural and agro-industrial waste by the action of fungi, such as Aspergillus spp., by solid-state fermentation (SSF). A wild strain of an Aspergillus sp. isolated in the Universidad Técnica del Norte (UTN) was used to obtain pectinolytic enzymes from dehydrated coffee waste (pulp and husk) derived from coffee cherries cultivated in the Ecuadorian Andean regions. It was possible to find a condition in which the production of pectinases (expressed as Enzymatic Activity (EA)) and the concentration of spores (S) were simultaneously maximized, using the response surface methodology, in a 3-level factorial design, by SSF in simple tray-type bioreactors. After the analysis and optimization of quadratic models, three confirmatory experiments were performed in the unique optimal condition recommended (35 °C and 79% relative humidity), obtaining 29.9 IU/g and 2.64 × 10⁶ #Sp./g for EA and S, respectively; these values coincided with those predicted by the quadratic models, demonstrating their validity. The values obtained in this study are similar to those previously obtained by other authors.

The global citrus-processing industry generates 15–32 million tonnes of waste annually. Lemon-processing residues—peels, seeds, and pomace—constitute 45–55% of fruit mass and harbour high-value bioactive compounds amenable to cascade valorisation. This review (Part I of a two-part series) examines green extraction technologies for recovering bioactive compounds from lemon waste streams. Following bibliometric analysis of 847 publications (2003–2025), this work delineates the compositional heterogeneity of lemon fractions and establishes a hierarchical framework for value-added products encompassing essential oils, pectin, polyphenols, seed oils, citric acid, industrial enzymes, α-cellulose, and nanocrystalline cellulose. Four sustainable extraction methodologies are systematically evaluated: ultrasound-assisted extraction, microwave-assisted extraction, supercritical CO₂ extraction, and enzyme-assisted extraction. Comparative assessment demonstrates yield improvements of 16–112% over conventional approaches, processing-time reductions of 89–98%, and energy savings up to 95%. Critical research gaps include fragmented single-product valorisation, insufficient techno-economic assessment, and limited industrial-scale validation. Integrated cascade biorefineries employing sequential green extraction protocols offer economically viable pathways for transforming lemon waste into diversified revenue streams. Industrial implementation, circular-economy integration, and techno-economic feasibility are addressed in Part II.

Este documento describe la historia de la tecnología de atmósferas controladas, sus avances tecnológicos y sus aplicaciones, proporcionando perspectivas de investigaciones en distintos campos de estudio. Para ello se ha desarrollado una revisión de información, sobre los distintos campos donde la tecnología ha sido aplicada y su eficiencia como alternativa de tratamiento. Los estudios relacionados con este campo generados hasta la fecha, están asociados con el efecto que produce la tecnología en las características organolépticas y funcionales de determinadas frutas (aroma, calidad, potencial antioxidante, polifenoles, etc.) y en la automatización de la tecnología (adaptaciones, monitoreo computarizado), así como el efecto en el campo de la electrónica. En la mayoría de los casos la tecnología ha mostrado una mayor eficiencia que en los métodos tradicionales. Se puede concluir que debido a la amplia alternativa de aplicación y la eficiencia de la de la tecnología de atmósferas controladas, se pueden generar estudios adicionales para complementar su desarrollo futuro.

El presente trabajo investigó el contenido de polifenoles totales, carotenos, ácido ascórbico, capacidad antioxidante y el color de Physalis peruviana L. al ser deshidratada a 60 °C mediante secador de bandejas a una velocidad de 3 m/s y mediante estufa a la misma temperatura. El contenido de polifenoles totales se evaluó con el método de Folin-Ciocalteu y la capacidad antioxidante por el método 2,2-Difenil-1-Picrilhidrazilo (DPPH), el color mediante CIELab, carotenos por espectrofotometría y ácido ascórbico por titulación. Se encontró que la fruta presentó una capacidad antioxidante de 237.3 y 260.7 µmolTE /100 g, un contenido de polifenoles totales de 129.90 y 124.86 mg GAE/100 g, un contenido de carotenos de 136.96 y 149.26 µg/g, mientras que el contenido de ácido ascórbico fue de 21.03 y 19.10 mg/100 g para fruta de madurez 3 y 5 respectivamente. La capacidad antioxidante presentó una correlación inversa con el contenido de polifenoles y ácido ascórbico, pero directa con el de carotenos. La mayor conservación de las propiedades estudiadas, especialmente en los carotenos, se observó con el secador de bandejas, por lo que se recomienda este método de procesamiento de deshidratación.