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Growing interest in lignocellulosic bioethanol stems from the European Union's renewable energy directive, targeting a global bioethanol output of 130 billion L to achieve a minimum threshold of 42.5%. Despite industrialization challenges, recent advancements, especially in crucial stages like pretreatment, hydrolysis, and fermentation, are transforming the landscape. This review delves into the progress of bioethanol production, addressing technological, environmental, and economic hurdles. Innovations such as deep eutectic solvent pretreatment and mechanocatalysis, offering advantages like 30% and 100% solid loading, respectively, surpass traditional techniques and enzymatic hydrolysis in yielding better results. Improved pretreatment methods, enzyme exploration, saccharification techniques, genetic engineering, and integrated biorefineries contribute to overall economic viability. Ongoing research involves techno-economic analysis for cost-effective strategies, aiming to enhance the competitiveness of lignocellulosic bioethanol production. Scrutinizing the feasibility of these innovative approaches not only highlights their potential to overcome existing shortcomings but also envisions a more attractive future for industrial bioethanol production. Embracing these advancements could pave the way for a vibrant and sustainable bioethanol industry.

Renewable energies can reduce emissions from fossil fuel-based power production by a significant amount, reducing climate change. Among the several options being investigated, hydrogen is now recognized as one of the primary enabling technologies for future large-scale and long-term green storage of renewable energy. However, using clean and renewable energy sources like water and sunlight is the best option. According to recent studies, photoelectrochemical (PEC) water splitting is a potential technology for creating hydrogen using free solar energy since hydrogen and oxygen gases may be easily identified in PEC. This study uses bibliometric and systematic literature review methodologies to examine the scientific understanding of PEC water splitting and hydrogen generation, evaluating 936 articles issued in the Web of Science database from 1970 to 2022. The authors looked at how PEC water splitting research has developed compared to prior research, what criteria make up practical approaches, and what subjects have emerged as new trends in reacting to changing situations. The key findings from the article analysis, future research potential, and practical implications for the field are discussed.

Years of study have shown that creating a commercial photoelectrode to solve particular bottlenecks, such as low charge separation and injection efficiency, short carrier diffusion length and lifespan, and poor stability, requires the employment of a variety of components. Developing photovoltaic-electrolysis, photocatalytic, and photoelectrochemical approaches to accelerate hydrogen production from solar energy has been highly competitive. Photoelectrochemical water splitting utilizing nanoporous materials is one of the promising approaches to produce hydrogen more efficiently, cost-effectively, and on a long-term basis. Nanoporous materials have been highly used in photoelectrochemical water-splitting systems and are crucial in numerous applications. Those materials have a porous structure and excellent conductivity, enabling the deposition of transition metal atoms and electrochemically active chemicals on a large active surface area. However, there remains a dearth of review articles exploring the application of nanoporous materials in photoelectrochemical reactions. Therefore, this review provides bibliometric statistics and various perspectives on a range of nanoporous materials, including indium, nickel, gold, copper, lead, silver, aluminum, silicon, tin, iron, zinc, titanium, bismuth vanadate, cadmium sulfide, and zeolites. Additionally, this review offers a comprehensive assessment of worldwide studies on utilizing nanoporous materials in photoelectrochemical cells. We show how morphological modifications to materials may improve charge transfer and, as a consequence, overall power conversion efficiency.ke The superior catalytic performance of nanostructures with varying levels of complexity has been discovered in photoelectrochemical reactions. Finally, signif

In this study, a deep eutectic solvent pretreated milled softwood mixture was impregnated with oxalic acid before performing a water hydrolysis to obtain glucose using a microwave. Analysis of variance of a central composite design (CCD) showed that both temperature and time were significant parameters to consider when studying the cellulose conversion, glucose yield and glucose selectivity. The optimal conditions were 174 °C and 2 h, which resulted in 27.7% cellulose conversion, 22.4% glucose yield and 81.1% glucose selectivity. Oxalic acid affected the amorphous domains of cellulose at low hydrolysis temperature, while both the amorphous and the crystalline regions were affected at high temperature. Successive treatments of the solid hydrolysis residues resulted in 98.4% cellulose conversion, 79.0% glucose yield and 80.3% selectivity. Bioethanol was produced from the recovered glucose within 24 h with a fermentation efficiency of 42.9%.

Advancements in plant space biology are required for the realization of human space exploration missions, where the re-supply of resources from Earth is not feasible. Until a few decades ago, space life science was focused on the impact of the space environment on the human body. More recently, the interest in plant space biology has increased because plants are key organisms in Bioregenerative Life Support Systems (BLSS) for the regeneration of resources and fresh food production. Moreover, plants play an important role in psychological support for astronauts. The definition of cultivation requirements for the design, realization, and successful operation of BLSS must consider the effects of space factors on plants. Altered gravitational fields and radiation exposure are the main space factors inducing changes in gene expression, cell proliferation and differentiation, signalling and physiological processes with possible consequences on tissue organization and organogenesis, thus on the whole plant functioning. Interestingly, the changes at the cellular and molecular levels do not always result in organismic or developmental changes. This apparent paradox is a current research challenge. In this paper, the main findings of gravity- and radiation-related research on higher plants are summarized, highlighting the knowledge gaps that are still necessary to fill. Existing experimental facilities to simulate the effect of space factors, as well as requirements for future facilities for possible experiments to achieve fundamental biology goals are considered. Finally, the need for making synergies among disciplines and for establishing global standard operating procedures for analyses and data collection in space experiments is highlighted.

Following on from the NASA twins’ study there has been a tremendous interest in the use of omics techniques in spaceflight. The individual space agency’s, NASA’s GeneLab, JAXA´s ibSLS and ESA-funded Space Omics Topical Team and the International Standards for Space Omics Processing (ISSOP) group have established several initiatives to support this growth. Here, we present recommendations from the Space Omics Topical Team to promote standard application of space omics in Europe. We focus on four main themes: i) continued participation in and co-ordination with international omics endeavours; ii) strengthening of the European space omics infrastructure including workforce and facilities; iii) capitalizing on the emerging opportunities in the commercial space sector, and iv) capitalizing on the emerging opportunities in human subjects research.

Discovering the adaptation mechanisms of plants to the space environment is essential for supporting human space exploration. Transcriptomic analyses allow the identification of adaptation response pathways by detecting changes in gene expression at the global genome level caused by the main factors of the space environment, namely altered gravity and cosmic radiation. This article reviews transcriptomic studies carried out from plants grown in spaceflights and in different ground-based microgravity simulators. Despite differences in plant growth conditions, these studies have shown that cell wall remodeling, oxidative stress, defense response, and photosynthesis are common altered processes in plants grown under spaceflight conditions. European scientists have significantly contributed to the acquisition of this knowledge, e.g., by showing the role of red light in the adaptation response of plants (EMCS experiments) and the mechanisms of cellular response and adaptation mostly affecting cell cycle regulation, using cell cultures in microgravity simulators.

In a microgravity environment, without any gravitropic signal, plants are not able to define and establish a longitudinal growth axis. Consequently, absorption of water and nutrients by the root and exposure of leaves to sunlight for efficient photosynthesis is hindered. In these conditions, other external cues can be explored to guide the direction of organ growth. Providing a unilateral light source can guide the shoot growth, but prolonged root exposure to light causes a stress response, affecting growth and development, and also affecting the response to other environmental factors. Here, we have investigated how the protection of the root from light exposure, while the shoot is illuminated, influences the direction of root growth in microgravity. We report that the light avoidance mechanism existing in roots guides their growth towards diminishing light and helps establish the proper longitudinal seedling axis in simulated microgravity conditions. This process is regulated by flavonols, as shown in the flavonoid-accumulating mutant transparent testa 3, which shows an increased correction of the root growth direction in microgravity, when the seedling is grown with the root protected from light. This finding may improve the efficiency of water and nutrient sourcing and photosynthesis under microgravity conditions, as they exist in space, contributing to better plant fitness and biomass production in space farming enterprises, necessary for space exploration by humans.

The European research community, via European Space Agency (ESA) spaceflight opportunities, has significantly contributed towards our current understanding of spaceflight biology. Recent molecular biology experiments include “omic” analysis, which provides a holistic and systems level understanding of the mechanisms underlying phenotypic adaptation. Despite vast interest in, and the immense quantity of biological information gained from space omics research, the knowledge of ESA-related space omics works as a collective remains poorly defined due to the recent exponential application of omics approaches in space and the limited search capabilities of pre-existing records. Thus, a review of such contributions is necessary to clarify and promote the development of space omics among ESA and ESA state members. To address this gap, in this review we: i) identified and summarised omics works led by European researchers, ii) geographically described these omics works, and iii) highlighted potential caveats in complex funding scenarios among ESA member states.

We performed a series of experiments to study the interaction between phototropism and gravitropism in Arabidopsis thaliana as part of the Seedling Growth Project on the International Space Station. Red-light-based and blue-light-based phototropism were examined in microgravity and at 1g, a control that was produced by an on-board centrifuge. At the end of the experiments, seedlings were frozen and brought back to Earth for gene profiling studies via RNASeq methods. In this paper, we focus on five genes identified in these space studies by their differential expression in space: one involved in auxin transport and four others encoding genes for: a methyltransferase subunit, a transmembrane protein, a transcription factor for endodermis formation, and a cytoskeletal element (an intermediate filament protein). Time course studies using mutant strains of these five genes were performed for blue-light and red-light phototropism studies as well as for gravitropism assays on ground. Interestingly, all five of the genes had some effects on all the tropisms under the conditions studied. In addition, RT-PCR analyses examined expression of the five genes in wild-type seedlings during blue-light-based phototropism. Previous studies have supported a role of both microfilaments and microtubules in tropism pathways. However, the most interesting finding of the present space studies is that NFL, a gene encoding an intermediate filament protein, plays a role in phototropism and gravitropism, which opens the possibility that this cytoskeletal element modulates signal transduction in plants.

Gravitropism and phototropism play a primary role in orienting root growth. Tropistic responses of roots mediated by gravity and light have been extensively investigated, and a complex mutual interaction occurs between these two tropisms. To date, most studies have been conducted in 1 g, microgravity, or simulated microgravity, whereas no studies investigated root phototropism in hypergravity. Therefore, we studied the effects of several gravity treatments with those of different light wavelengths on root growth orientation. Here, we report growth and curvature of Brassica oleracea roots under different g levels, from simulated microgravity up to 20 g, and unilateral illumination with different spectral treatments provided by light emitting diodes. Microgravity was simulated with a random positioning machine whereas hypergravity conditions were obtained using the Large Diameter Centrifuge at the laboratories of the European Space Agency in the Netherlands. Four light treatments (white light, blue light, red light, and dark) were used in this study. Overall, roots of seedlings grown in the dark were longer than those developed under unilateral light treatments, regardless of the gravity level. Unilateral blue light or white light stimulated a negative phototropism of roots under all g levels, and root curvature was not affected by either hypergravity or simulated microgravity compared to 1 g. Results also confirmed previous findings on the effect of light intensity on root curvature and highlighted the relevance of blue-light photon flux density in root phototropism. Roots illuminated with red light showed a weak curvature in simulated microgravity but not in hypergravity. Moreover, root curvature under red light was similar to dark-grown roots in all g levels, suggesting a possible involvement of surface-dependent phenomena in root skewing under either red light or dark conditions. Further studies can confirm phototropic responses of B. oleracea in the weightless en

Long-duration space missions will need to rely on the use of plants in bio-regenerative life support systems (BLSSs) because these systems can produce fresh food and oxygen, reduce carbon dioxide levels, recycle metabolic waste, and purify water. In this scenario, the need for new experiments on the effects of altered gravity conditions on plant biological processes is increasing, and significant efforts should be devoted to new ideas aimed at increasing the scientific output and lowering the experimental costs. Here, we report the design of an easy-to-produce and inexpensive device conceived to analyze the effect of interaction between gravity and light on root tropisms. Each unit consisted of a polystyrene multi-slot rack with light-emitting diodes (LEDs), capable of holding Petri dishes and assembled with a particular filter-paper folding. The device was successfully used for the ROOTROPS (for root tropisms) experiment performed in the Large Diameter Centrifuge (LDC) and Random Positioning Machine (RPM) at ESA's European Space Research and Technology centre (ESTEC). During the experiments, four light treatments and six gravity conditions were factorially combined to study their effects on root orientation of Brassica oleracea seedlings. Light treatments (red, blue, and white) and a dark condition were tested under four hypergravity levels (20 g, 15 g, 10 g, 5 g), a 1 g control, and a simulated microgravity (RPM) condition. Results of validation tests showed that after 24 h, the assembled system remained unaltered, no slipping or displacement of seedlings occurred at any hypergravity treatment or on the RPM, and seedlings exhibited robust growth. Overall, the device was effective and reliable in achieving scientific goals, suggesting that it can be used for ground-based research on phototropism-gravitropism interactions. Moreover, the concepts developed can be further expanded for use in future spaceflight experiments with plants.