Stepping stones in CO₂ utilization:Synthesis and evaluation of oxalic- and glycolic acid (co)polyesters

Plastic materials have become indispensable in everyday life because of their versatility, high durability, lightness and low cost. As a consequence their demand continues to increase steadily, accompanied by an increasing requirement of fossil resources, both for energy and building blocks, as about 99 % of the current feedstock for polymers is fossil-based. Unfortunately, this trend is accompanied by higher emissions by the industry and leakage during production, transport and through consumer usage and disposal. This mismanaged plastic waste causes unprecedented harm to ecosystems. The aforementioned issues prompt the need to rethink the entire plastic value chain. While for energy many options are available to decouple from fossil feedstocks, for plastic materials the only alternative carbon sources are biomass, existing plastics (via recycling) and in the long-term CO2. The fact that CO2 is naturally abundant, nontoxic, inexpensive, a non-oxidant and renewable, makes it a promising feedstock. Finally, the use of CO2 as feedstock can leade to negative emissions required to reach “net zero” in the second half of this century. The research presented in this thesis is part of the OCEAN (EU Horizon 2020 Spire program) project in which a new route to produce polymers using CO2 as circular feedstock is developed. CO2 can be electrochemically reduced to formic acid derivatives that can be subsequently converted into useful monomers such as oxalic acid and glycolic acid. We focused on investigating synthesis routes to produce polyesters based on those monomers and on studying their properties and assessing potential applications

Safety and efficacy of the bumped kinase inhibitor BKI-1553 in pregnant sheep experimentally infected with Neospora caninum tachyzoites

Neospora caninum is one of the main causes of abortion in cattle, and recent studies have highlighted its relevance as an abortifacient in small ruminants. Vaccines or drugs for the control of neosporosis are lacking. Bumped kinase inhibitors (BKIs), which are ATP-competitive inhibitors of calcium dependent protein kinase 1 (CDPK1), were shown to be highly efficacious against several apicomplexan parasites in vitro and in laboratory animal models. We here present the pharmacokinetics, safety and efficacy of BKI-1553 in pregnant ewes and foetuses using a pregnant sheep model of N. caninum infection. BKI-1553 showed exposure in pregnant ewes with trough concentrations of approximately 4 µM, and of 1 µM in foetuses. Subcutaneous BKI-1553 administration increased rectal temperatures shortly after treatment, and resulted in dermal nodules triggering a slight monocytosis after repeated doses at short intervals. BKI-1553 treatment decreased fever in infected pregnant ewes already after two applications, resulted in a 37–50% reduction in foetal mortality, and modulated immune responses; IFN¿ levels were increased early after infection and IgG levels were reduced subsequently. N. caninum was abundantly found in placental tissues; however, parasite detection in foetal brain tissue decreased from 94% in the infected/untreated group to 69–71% in the treated groups. In summary, BKI-1553 confers partial protection against abortion in a ruminant experimental model of N. caninum infection during pregnancy. In addition, reduced parasite detection, parasite load and lesions in foetal brains were observed

Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer

To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L−1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4°C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature

Stepping stones in CO2 utilization: Synthesis and evaluation of oxalic- and glycolic acid (co)polyesters

Plastic materials have become indispensable in everyday life because of their versatility, high durability, lightness and low cost. As a consequence their demand continues to increase steadily, accompanied by an increasing requirement of fossil resources, both for energy and building blocks, as about 99 % of the current feedstock for polymers is fossil-based. Unfortunately, this trend is accompanied by higher emissions by the industry and leakage during production, transport and through consumer usage and disposal. This mismanaged plastic waste causes unprecedented harm to ecosystems. The aforementioned issues prompt the need to rethink the entire plastic value chain. While for energy many options are available to decouple from fossil feedstocks, for plastic materials the only alternative carbon sources are biomass, existing plastics (via recycling) and in the long-term CO2. The fact that CO2 is naturally abundant, nontoxic, inexpensive, a non-oxidant and renewable, makes it a promising feedstock. Finally, the use of CO2 as feedstock can leade to negative emissions required to reach “net zero” in the second half of this century. The research presented in this thesis is part of the OCEAN (EU Horizon 2020 Spire program) project in which a new route to produce polymers using CO2 as circular feedstock is developed. CO2 can be electrochemically reduced to formic acid derivatives that can be subsequently converted into useful monomers such as oxalic acid and glycolic acid. We focused on investigating synthesis routes to produce polyesters based on those monomers and on studying their properties and assessing potential applications

The potential of oxalic - and glycolic acid based polyesters (review). Towards CO2 as a feedstock (Carbon Capture and Utilization - CCU)

Plastic materials are indispensable in everyday life because of their versatility, high durability, lightness and cost effectiveness. As a consequence, worldwide plastic consumption will continue to grow from around 350 million metric tons per annum today to an estimated 1 billion metric tons per annum in 2050. For applications where polymers are applied in the environment or for applications where polymers have a bigger chance of ending up in the environment, (bio)degradable polymers need to be developed to stop endless accumulation of non degradable polymers irreversibly littering our planet.  As monomers and polymers represent more than 80% of the chemical industry's total production volume, a transition from fossil feedstock today (99% of the current feedstock for polymers is fossil-based) to a significantly larger percentage of renewable feedstock in the future (carbon that is already ''above the ground'') will be required to meet the greenhouse gas reduction targets of the Paris Agreement ( > 80% CO2 reduction target for the European Chemical Industry sector in 2050).  The combination of the predicted polymer market growth and the emergence of new feedstocks creates a fantastic opportunity for novel sustainable polymers. To replace fossil based feedstock, there are only three sustainable alternative sources: biomass, CO2 and existing plastics (via recycling). The ultimate circular feedstock would be CO2: it can be electrochemically reduced to formic acid derivatives that can subsequently be converted into useful monomers such as glycolic acid and oxalic acid. In order to assess the future potential for these polyester building blocks, we will review the current field of polyesters based on these two monomers. Representative synthesis methods, general properties, general degradation mechanisms, and recent applications will be discussed in this review. The application potential of these polyesters for a wide range of purposes, as a function of production cost, will also be assessed. It is important to note that polymers derived from CO2 do not necessarily always lead to lower net overall CO2 emissions (during production of after use, e.g. degradation in landfills). This needs to be evaluated using robust LCA's and this information is currently not available for the materials discussed in this review