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Lignin is an abundant source of renewable aromatics that has long been targeted for valorization. Traditionally, the inherent heterogeneity and reactivity of lignin has relegated it to direct combustion, but its higher energy density compared with polysaccharides makes it an ideal candidate for biofuel production. This Review critically assesses lignin’s potential as a substrate for sustainable aviation fuel blendstocks. Lignin can generate the necessary cyclic compounds for a fully renewable, sustainable aviation fuel when integrated with current paraffinic blends and can meet the current demand 2.5 times over. Using an energy-centric analysis, we show that lignin conversion technologies have the near-term potential to match the enthalpic yields of existing commercial sustainable aviation fuel production processes. Key factors influencing the viability of technologies for converting lignin to sustainable aviation fuel include lignin structure, delignification extent, depolymerization performance, and the development of stable and tunable deoxygenation catalysts. Lignin is an abundant source of renewable aromatic carbon and is of interest as a feedstock for sustainable fuels. This Review provides an overview of production technologies, jet fuel requirements, effects of lignin chemistry, depolymerization techniques, upgrading of bio-oils and challenges for catalysis using real biomass feedstocks.

A catalyst (NiW/Ti-USY) was prepared via an impregnation method. Its catalytic performance was investigated for the hydrodeoxygenation (HDO) of Jatropha oil. It was found that the support composition significantly influenced the Lewis acid site concentration, thereby affecting the deoxygenation performance. The catalyst exhibited optimal activity when the Ti loading reached 9 wt%. Furthermore, under the same support conditions, a Ni/W mass ratio of 1:9 and a total NiW loading of 30% resulted in the best catalytic performance, achieving a deoxygenation rate exceeding 90% and a minimum olefin content of 9.64%. GC-MS analysis of the product oil revealed a ratio of (C15 + C17)/(C16 + C18) greater than 10, indicating that the decarbonylation/decarboxylation (DCO/DCO₂) pathway dominated the hydrodeoxygenation process.

The modern Pacific Ocean hosts the largest oxygen-deficient zones (ODZs), where oxygen concentrations are so low that nitrate is used to respire organic matter. The history of the ODZs may offer key insights into ocean deoxygenation under future global warming. In a 12-My record from the southeastern Pacific, we observe a >10‰ increase in foraminifera-bound nitrogen isotopes (15N/14N) since the late Miocene (8 to 9 Mya), indicating large ODZs expansion. Coinciding with this change, we find a major increase in the nutrient content of the ocean, reconstructed from phosphorus and iron measurements of hydrothermal sediments at the same site. Whereas global warming studies cast seawater oxygen concentrations as mainly dependent on climate and ocean circulation, our findings indicate that modern ODZs are underpinned by historically high concentrations of seawater phosphate.

HighlightsGene-engineering tumor cell membrane with CD47 over-expression is achieved to improve the macrophage-mediated phagocytosis of tumor cells by blocking CD47 immune checkpoint.A cascade-enzyme nanoreactor combining tumor enzyme dynamic therapy, phototherapy, and deoxygenation-activated chemotherapy is proposed. Glucose oxidase and chloroperoxidase can generate sufficient HClO to kill normoxic tumor cells, and tirapazamine can be subsequently activated to kill hypoxic tumor cells.The enzyme-mediated elevation of reactive oxygen species (ROS) at the tumor sites has become an emerging strategy for regulating intracellular redox status for anticancer treatment. Herein, we proposed a camouflaged bionic cascaded-enzyme nanoreactor based on Ti3C2 nanosheets for combined tumor enzyme dynamic therapy (EDT), phototherapy and deoxygenation-activated chemotherapy. Briefly, glucose oxidase (GOX) and chloroperoxidase (CPO) were chemically conjugated onto Ti3C2 nanosheets, where the deoxygenation-activated drug tirapazamine (TPZ) was also loaded, and the Ti3C2-GOX-CPO/TPZ (TGCT) was embedded into nanosized cancer cell-derived membrane vesicles with high-expressed CD47 (meTGCT). Due to biomimetic membrane camouflage and CD47 overexpression, meTGCT exhibited superior immune escape and homologous targeting capacities, which could effectively enhance the tumor preferential targeting and internalization. Once internalized into tumor cells, the cascade reaction of GOX and CPO could generate HClO for efficient EDT. Simultaneously, additional laser irradiation could accelerate the enzymic-catalytic reaction rate and increase the generation of singlet oxygen (1O2). Furthermore, local hypoxia environment with the oxygen depletion by EDT would activate deoxygenation-sensitive prodrug for additional chemotherapy. Consequently, meTGCT exhibits amplified synergistic therapeutic effects of tumor phototherapy, EDT and chemotherapy for efficient tumor inhibition. This intelligent cascaded-enzyme nanoreactor provides a promising approach to achieve concurrent and significant antitumor therapy.

The Arabian Gulf (AG) exports hypersaline, dense waters into the Sea of Oman (SOO), replaced by fresher inflowing surface waters from the Indian Ocean. We investigate the impact of recent AG warming on its exchange with the SOO and the implications this has on the AG biogeochemistry. Using an eddy‐resolving hindcast model simulation, we analyze the hydrography and biogeochemistry of the AG and the SOO from 1980 to 2018. Our study reveals that changes in summer surface winds have accelerated AG warming and weakened it in the SOO, reducing the density gradient and water exchange between the two seas during late summer. This has led to nutrient buildup, increased productivity, and heightened deoxygenation and acidification in the AG. These findings underscore how subtle wind changes can exacerbate the vulnerability of marginal seas to climate change and stress the need to properly represent regional winds in global climate models. Plain Language Summary The Arabian Gulf (AG) (also known as Persian Gulf) produces dense, salty water that flows into the SOO, while it receives fresher water from the Indian Ocean. This study investigates how the recent rapid warming of the AG affects this exchange with the SOO and its impact on the Gulf's environment. Using a computer simulation to model the AG's evolution from 1980 to 2018, we discovered that changes in surface winds have warmed the AG and weakened its connection to the SOO during summer. This led to nutrient accumulation, increased micro‐algae growth, decreased oxygen levels, and increased water acidity in the AG. These findings highlight how minor changes in wind patterns can exacerbate the effects of climate change in specific seas, emphasizing the need to improve the representation of local winds in climate models. Key Points Recent changes in surface winds have accelerated warming in the Arabian Gulf (AG) while dampening it in the Sea of Oman (SOO) The faster warming in the AG has reduced exchange with the SOO, leading to a buildup of nutrients and biomass in the Gulf This increased productivity has caused a rise in respiration, thereby accelerating deoxygenation and acidification in the Gulf

Reductive electrosynthesis has faced long-standing challenges in applications to complex organic substrates at scale. Here, we show how decades of research in lithium-ion battery materials, electrolytes, and additives can serve as an inspiration for achieving practically scalable reductive electrosynthetic conditions for the Birch reduction. Specifically, we demonstrate that using a sacrificial anode material (magnesium or aluminum), combined with a cheap, nontoxic, and water-soluble proton source (dimethylurea), and an overcharge protectant inspired by battery technology [tris(pyrrolidino)phosphoramide] can allow for multigram-scale synthesis of pharmaceutically relevant building blocks. We show how these conditions have a very high level of functional-group tolerance relative to classical electrochemical and chemical dissolving-metal reductions. Finally, we demonstrate that the same electrochemical conditions can be applied to other dissolving metal–type reductive transformations, including McMurry couplings, reductive ketone deoxygenations, and epoxide openings.

One of the most important physical characteristics driving lifecycle events in lakes is stratification. Already subtle variations in the timing of stratification onset and break-up (phenology) are known to have major ecological effects, mainly by determining the availability of light, nutrients, carbon and oxygen to organisms. Despite its ecological importance, historic and future global changes in stratification phenology are unknown. Here, we used a lake-climate model ensemble and long-term observational data, to investigate changes in lake stratification phenology across the Northern Hemisphere from 1901 to 2099. Under the high-greenhouse-gas-emission scenario, stratification will begin 22.0 ± 7.0 days earlier and end 11.3 ± 4.7 days later by the end of this century. It is very likely that this 33.3 ± 11.7 day prolongation in stratification will accelerate lake deoxygenation with subsequent effects on nutrient mineralization and phosphorus release from lake sediments. Further misalignment of lifecycle events, with possible irreversible changes for lake ecosystems, is also likely. Stratification has a considerable influence on lake ecology, but there is little understanding of past or future changes in its seasonality. Here, the authors use modelling and empirical data to determine that between 1901–2099, climate change causes stratification to start earlier and end later.

All Earth System models project a consistent decrease in the oxygen content of oceans for the coming decades because of ocean warming, reduced ventilation and increased stratification. But large uncertainties for these future projections of ocean deoxygenation remain for the subsurface tropical oceans where the major oxygen minimum zones are located. Here, we combine global warming projections, model-based estimates of natural short-term variability, as well as data and model estimates of the Last Glacial Maximum (LGM) ocean oxygenation to gain some insights into the major mechanisms of oxygenation changes across these different time scales. We show that the primary uncertainty on future ocean deoxygenation in the subsurface tropical oceans is in fact controlled by a robust compensation between decreasing oxygen saturation (O2sat) due to warming and decreasing apparent oxygen utilization (AOU) due to increased ventilation of the corresponding water masses. Modelled short-term natural variability in subsurface oxygen levels also reveals a compensation between O2sat and AOU, controlled by the latter. Finally, using a model simulation of the LGM, reproducing data-based reconstructions of past ocean (de)oxygenation, we show that the deoxygenation trend of the subsurface ocean during deglaciation was controlled by a combination of warming-induced decreasing O2sat and increasing AOU driven by a reduced ventilation of tropical subsurface waters. This article is part of the themed issue ‘Ocean ventilation and deoxygenation in a warming world’.

With the aim to solve the serious problem of white plastic pollution, we report herein a low-cost process to quantitatively convert polyethylene terephthalate (PET) into p -xylene (PX) and ethylene glycol (EG) over modified Cu/SiO 2 catalyst using methanol as both solvent and hydrogen donor. Kinetic and in-situ Fourier-transform infrared spectroscopy (FTIR) studies demonstrate that the degradation of PET into PX involves tandem PET methanolysis and dimethyl terephthalate (DMT) selective hydro-deoxygenation (HDO) steps with the in-situ produced H 2 from methanol decomposition at 210 °C. The overall high activities are attributed to the high Cu + /Cu 0 ratio derived from the dense and granular copper silicate precursor, as formed by the induction of proper NaCl addition during the hydrothermal synthesis. This hydrogen-free one-pot approach allows to directly produce gasoline fuels and antifreeze components from waste poly-ester plastic, providing a feasible solution to the plastic problem in islands. To solve the serious problem of white plastic pollution many degradation routes are being investigated. Here the authors show a H 2 -free low-cost Cu/SiO 2 catalyzed process to quantitatively convert polyethylene terephthalate into p-xylene and ethylene glycol in one pot with methanol as both the solvent and hydrogen source at 210 °C.