Recent advances in catalytic and non-catalytic epoxidation of terpenes: a pathway to bio-based polymers from waste biomass.

Epoxides derived from waste biomass are a promising avenue for the production of bio-based polymers, including polyamides, polyesters, polyurethanes, and polycarbonates. This review article explores recent efforts to develop both catalytic and non-catalytic processes for the epoxidation of terpene, employing a variety of oxidizing agents and techniques for process intensification. Experimental investigations into the epoxidation of limonene have shown that these methods can be extended to other terpenes. To optimize the epoxidation of bio-based terpene, there is a need to develop continuous processes that address limitations in mass and heat transfer. This review discusses flow chemistry and innovative reactor designs as part of a multi-scale approach aimed at industrial transformation. These methods facilitate continuous processing, improve mixing, and either eliminate or reduce the need for solvents by enhancing heat transfer capabilities. Overall, the objective of this review is to contribute to the development of commercially viable processes for producing bio-based epoxides from waste biomass.

A foam column system harvesting freshwater algae for biodiesel production: An experiment and process model evaluations.

The purpose of this study was to examine the application of the mathematical model of drift flux to the experimental results of the effect of cationic trimethyl-ammonium bromide (CTAB)-aided continuous foam flotation harvesting on the lipid content in Chlorella vulgaris microalgae. An experiment was conducted to determine the effect of the operating conditions on the enrichment factor (EF) and percentage recovery efficiency (%RE), where the flow rates at the inlet and bottom outlet remained constant. Data for the binary system (without algae) and ternary system (with algae) in an equal-area foam column show that the EF decreases linearly with increasing initial CTAB concentrations ranging from 30 to 75 mg/L for three levels of the studied air volumetric flow rate range (1-3) L/min. The percentage harvesting efficiency increased with increasing initial CTAB concentration and air volumetric flow rate to 96 % in the binary systems and 94 % in the ternary systems. However, in the foam column with the riser used in the three systems, a lower volume of liquid foam in the upward outlet stream resulted in a lower RE% than that of the column without the riser. The objective function of EF for the system with algae increased when the initial CTAB concentration was increased from 30 to 45 mg/L in the foam column with a riser for all air flow rates, and after 45 mg/L, a sudden drop in the microalgae EF was observed. In the comparison between the foam column with and without the riser for the system with algae, the optimum EF was 145 for the design of the column with the riser and 139 for the column without the riser.

TRPM7 deficiency exacerbates cardiovascular and renal damage induced by aldosterone-salt.

Hyperaldosteronism causes cardiovascular disease as well as hypomagnesemia. Mechanisms are ill-defined but dysregulation of TRPM7, a Mg2+-permeable channel/α-kinase, may be important. We examined the role of TRPM7 in aldosterone-dependent cardiovascular and renal injury by studying aldosterone-salt treated TRPM7-deficient (TRPM7+/Δkinase) mice. Plasma/tissue [Mg2+] and TRPM7 phosphorylation were reduced in vehicle-treated TRPM7+/Δkinase mice, effects recapitulated in aldosterone-salt-treated wild-type mice. Aldosterone-salt treatment exaggerated vascular dysfunction and amplified cardiovascular and renal fibrosis, with associated increased blood pressure in TRPM7+/Δkinase mice. Tissue expression of Mg2+-regulated phosphatases (PPM1A, PTEN) was downregulated and phosphorylation of Smad3, ERK1/2, and Stat1 was upregulated in aldosterone-salt TRPM7-deficient mice. Aldosterone-induced phosphorylation of pro-fibrotic signaling was increased in TRPM7+/Δkinase fibroblasts, effects ameliorated by Mg2+ supplementation. TRPM7 deficiency amplifies aldosterone-salt-induced cardiovascular remodeling and damage. We identify TRPM7 downregulation and associated hypomagnesemia as putative molecular mechanisms underlying deleterious cardiovascular and renal effects of hyperaldosteronism.

Synthesis of cyclic α-pinane carbonate - a potential monomer for bio-based polymers.

This work reports the first known synthesis of α-pinane carbonate from an α-pinene derivative. Pinane carbonate is potentially useful as a monomer for poly(pinane carbonate), which would be a sustainable bio-based polymer. α-Pinene is a major waste product from the pulp and paper industries and the most naturally abundant monoterpene in turpentine oil. α-Pinene is routinely converted to pinene oxide and pinanediol, but no study has yet demonstrated the conversion of pinanediol into α-pinane carbonate. Here, α-pinane carbonate was synthesised via carboxylation of α-pinanediol with dimethyl carbonate under base catalysis using triazabicyclodecene guanidine (TBD). 81.1 ± 2.8% α-pinane carbonate yield was achieved at 98.7% purity. The produced α-pinane carbonate was a white crystalline solid with a melting point of 86 °C. It was characterised using FTIR, NMR, GCMS and a quadrupole time-of-flight (QTOF) mass spectrometer. The FTIR exhibited a C[double bond, length as m-dash]O peak at 1794 cm-1 confirming the presence of a cyclic carbonate. GCMS showed that the α-pinane carbonate fragments with loss of CO2, forming pinene epoxide. Base hydrolysis of the α-pinane carbonate using NaOH/ethanol/water regenerated the pinanediol with formations of Na2CO3.

Osteoprotegerin regulates vascular function through syndecan-1 and NADPH oxidase-derived reactive oxygen species.

Osteogenic factors, such as osteoprotegerin (OPG), are protective against vascular calcification. However, OPG is also positively associated with cardiovascular damage, particularly in pulmonary hypertension, possibly through processes beyond effects on calcification. In the present study, we focused on calcification-independent vascular effects of OPG through activation of syndecan-1 and NADPH oxidases (Noxs) 1 and 4. Isolated resistance arteries from Wistar-Kyoto (WKY) rats, exposed to exogenous OPG, studied by myography exhibited endothelial and smooth muscle dysfunction. OPG decreased nitric oxide (NO) production, eNOS activation and increased reactive oxygen species (ROS) production in endothelial cells. In VSMCs, OPG increased ROS production, H2O2/peroxynitrite levels and activation of Rho kinase and myosin light chain. OPG vascular and redox effects were also inhibited by the syndecan-1 inhibitor synstatin (SSNT). Additionally, heparinase and chondroitinase abolished OPG effects on VSMCs-ROS production, confirming syndecan-1 as OPG molecular partner and suggesting that OPG binds to heparan/chondroitin sulphate chains of syndecan-1. OPG-induced ROS production was abrogated by NoxA1ds (Nox1 inhibitor) and GKT137831 (dual Nox1/Nox4 inhibitor). Tempol (SOD mimetic) inhibited vascular dysfunction induced by OPG. In addition, we studied arteries from Nox1 and Nox4 knockout (KO) mice. Nox1 and Nox4 KO abrogated OPG-induced vascular dysfunction. Vascular dysfunction elicited by OPG is mediated by a complex signalling cascade involving syndecan-1, Nox1 and Nox4. Our data identify novel molecular mechanisms beyond calcification for OPG, which may underlie vascular injurious effects of osteogenic factors in conditions such as hypertension and/or diabetes.

Development of rapid and selective epoxidation of α-pinene using single-step addition of H2O2 in an organic solvent-free process.

This study reports substantial improvement in the process for oxidising α-pinene, using environmentally friendly H2O2 at high atom economy (∼93%) and selectivity to α-pinene oxide (100%). The epoxidation of α-pinene with H2O2 was catalysed by tungsten-based polyoxometalates without any solvent. The variables in the screening parameters were temperatures (30-70 °C), oxidant amount (100-200 mol%), acid concentrations (0.02-0.09 M) and solvent types (i.e., 1,2-dichloroethane, toluene, p-cymene and acetonitrile). Screening the process parameters revealed that almost 100% selective epoxidation of α-pinene to α-pinene oxide was possible with negligible side product formation within a short reaction time (∼20 min), using process conditions of a 50 °C temperature in the absence of solvent and α-pinene/H2O2/catalyst molar ratio of 5 : 1 : 0.01. A kinetic investigation showed that the reaction was first-order for α-pinene and catalyst concentration, and a fractional order (∼0.5) for H2O2 concentration. The activation energy (E a) for the epoxidation of α-pinene was ∼35 kJ mol-1. The advantages of the epoxidation reported here are that the reaction could be performed isothermally in an organic solvent-free environment to enhance the reaction rate, achieving nearly 100% selectivity to α-pinene oxide.

Downregulation of PPARα during Experimental Left Ventricular Hypertrophy Is Critically Dependent on Nox2 NADPH Oxidase Signalling.

Pressure overload-induced left ventricular hypertrophy (LVH) is initially adaptive but ultimately promotes systolic dysfunction and chronic heart failure. Whilst underlying pathways are incompletely understood, increased reactive oxygen species generation from Nox2 NADPH oxidases, and metabolic remodelling, largely driven by PPARα downregulation, are separately implicated. Here, we investigated interaction between the two as a key regulator of LVH using in vitro, in vivo and transcriptomic approaches. Phenylephrine-induced H9c2 cardiomyoblast hypertrophy was associated with reduced PPARα expression and increased Nox2 expression and activity. Pressure overload-induced LVH and systolic dysfunction induced in wild-type mice by transverse aortic constriction (TAC) for 7 days, in association with Nox2 upregulation and PPARα downregulation, was enhanced in PPARα-/- mice and prevented in Nox2-/- mice. Detailed transcriptomic analysis revealed significantly altered expression of genes relating to PPARα, oxidative stress and hypertrophy pathways in wild-type hearts, which were unaltered in Nox2-/- hearts, whilst oxidative stress pathways remained dysregulated in PPARα-/- hearts following TAC. Network analysis indicated that Nox2 was essential for PPARα downregulation in this setting and identified preferential inflammatory pathway modulation and candidate cytokines as upstream Nox2-sensitive regulators of PPARα signalling. Together, these data suggest that Nox2 is a critical driver of PPARα downregulation leading to maladaptive LVH.

Chanzyme TRPM7 protects against cardiovascular inflammation and fibrosis.

AIMS: Transient Receptor Potential Melastatin 7 (TRPM7) cation channel is a chanzyme (channel + kinase) that influences cellular Mg2+ homeostasis and vascular signalling. However, the pathophysiological significance of TRPM7 in the cardiovascular system is unclear. The aim of this study was to investigate the role of this chanzyme in the cardiovascular system focusing on inflammation and fibrosis. METHODS AND RESULTS: TRPM7-deficient mice with deletion of the kinase domain (TRPM7+/Δkinase) were studied and molecular mechanisms investigated in TRPM7+/Δkinase bone marrow-derived macrophages (BMDM) and co-culture systems with cardiac fibroblasts. TRPM7-deficient mice had significant cardiac hypertrophy, fibrosis, and inflammation. Cardiac collagen and fibronectin content, expression of pro-inflammatory mediators (SMAD3, TGFß) and cytokines [interleukin (IL)-6, IL-10, IL-12, tumour necrosis factor-α] and phosphorylation of the pro-inflammatory signalling molecule Stat1, were increased in TRPM7+/Δkinase mice. These processes were associated with infiltration of inflammatory cells (F4/80+CD206+ cardiac macrophages) and increased galectin-3 expression. Cardiac [Mg2+]i, but not [Ca2+]i, was reduced in TRPM7+/Δkinase mice. Calpain, a downstream TRPM7 target, was upregulated (increased expression and activation) in TRPM7+/Δkinase hearts. Vascular functional and inflammatory responses, assessed in vivo by intra-vital microscopy, demonstrated impaired neutrophil rolling, increased neutrophil: endothelial attachment and transmigration of leucocytes in TRPM7+/Δkinase mice. TRPM7+/Δkinase BMDMs had increased levels of galectin-3, IL-10, and IL-6. In co-culture systems, TRPM7+/Δkinase macrophages increased expression of fibronectin, proliferating cell nuclear antigen, and TGFß in cardiac fibroblasts from wild-type mice, effects ameliorated by MgCl2 treatment. CONCLUSIONS: We identify a novel anti-inflammatory and anti-fibrotic role for TRPM7 and suggest that its protective effects are mediated, in part, through Mg2+-sensitive processes.

ER stress and Rho kinase activation underlie the vasculopathy of CADASIL.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) leads to premature stroke and vascular dementia. Mechanism-specific therapies for this aggressive cerebral small vessel disease are lacking. CADASIL is caused by NOTCH3 mutations that influence vascular smooth muscle cell (VSMC) function through unknown processes. We investigated molecular mechanisms underlying the vasculopathy in CADASIL focusing on endoplasmic reticulum (ER) stress and RhoA/Rho kinase (ROCK). Peripheral small arteries and VSMCs were isolated from gluteal biopsies of CADASIL patients and mesentery of TgNotch3R169C mice (CADASIL model). CADASIL vessels exhibited impaired vasorelaxation, blunted vasoconstriction, and hypertrophic remodeling. Expression of NOTCH3 and ER stress target genes was amplified and ER stress response, Rho kinase activity, superoxide production, and cytoskeleton-associated protein phosphorylation were increased in CADASIL, processes associated with Nox5 upregulation. Aberrant vascular responses and signaling in CADASIL were ameliorated by inhibitors of Notch3 (γ-secretase inhibitor), Nox5 (mellitin), ER stress (4-phenylbutyric acid), and ROCK (fasudil). Observations in human CADASIL were recapitulated in TgNotch3R169C mice. These findings indicate that vascular dysfunction in CADASIL involves ER stress/ROCK interplay driven by Notch3-induced Nox5 activation and that NOTCH3 mutation-associated vascular pathology, typical in cerebral vessels, also manifests peripherally. We define Notch3-Nox5/ER stress/ROCK signaling as a putative mechanism-specific target and suggest that peripheral artery responses may be an accessible biomarker in CADASIL.

Scale-up and Sustainability Evaluation of Biopolymer Production from Citrus Waste Offering Carbon Capture and Utilisation Pathway.

Invited for this month's cover picture is the group of Dr Miao Guo from Department of Chemical Engineering at the Imperial College London (UK). The cover picture shows modelling research on the co-polymerisation of waste-sourced limonene oxide with CO2 to produce poly(limonene carbonate), which offers a sustainable pathway to achieve carbon capture and utilisation. A computational approach to process design was integrated with sustainability evaluation to model this synthetic pathway and identify the environmental-damaging and performance-limiting steps for further improvement. Our research highlights the potential of closed-loop manufacturing systems with waste recovery, which is instrumental in building a sustainable circular economy. Read the full text of their Full Paper at 10.1002/open.201900015.

Scale-up and Sustainability Evaluation of Biopolymer Production from Citrus Waste Offering Carbon Capture and Utilisation Pathway.

Poly(limonene carbonate) (PLC) has been highlighted as an attractive substitute to petroleum derived plastics, due to its utilisation of CO2 and bio-based limonene as feedstocks, offering an effective carbon capture and utilisation pathway. Our study investigates the techno-economic viability and environmental sustainability of a novel process to produce PLC from citrus waste derived limonene, coupled with an anaerobic digestion process to enable energy cogeneration and waste recovery maximisation. Computational process design was integrated with a life cycle assessment to identify the sustainability improvement opportunities. PLC production was found to be economically viable, assuming sufficient citrus waste is supplied to the process, and environmentally preferable to polystyrene (PS) in various impact categories including climate change. However, it exhibited greater environmental burdens than PS across other impact categories, although the environmental performance could be improved with a waste recovery system, at the cost of a process design shift towards energy generation. Finally, our study quantified the potential contribution of PLC to mitigating the escape of atmospheric CO2 concentration from the planetary boundary. We emphasise the importance of a holistic approach to process design and highlight the potential impacts of biopolymers, which is instrumental in solving environmental problems facing the plastic industry and building a sustainable circular economy.

Techno-Economic Analysis of Glycerol Valorization via Catalytic Applications of Sulphonic Acid-Functionalized Copolymer Beads.

The design of experiments response surface analysis was employed for the first time to study the effect of divinylbenzene (DVB) (20-80 wt. %), diluent (0-100 wt.%), and mixing (200-900 rpm) on the beads' physical properties and on swelling ability. The beads with the highest performances, in terms of mechanical stability, surface area, and swelling ability, were sulphated, and tested in converting glycerol to a valuable product "solketal." Process options for glycerol valorization to solketal using synthesized sulphonic acid-functionalized styrene-divinylbenzene (ST-DVB-SO3H) copolymer beads and techno-economic analysis of the processes have been investigated. Three processes were evaluated: two one-stage processes at 8.5 wt.% catalyst and 50°C, based on either 6:1 acetone to glycerol molar ratio (87% conversion) or 12:1 (98% glycerol to solketal conversion), and a two-stage route (two acetone additions), where ≥98% conversion can be achieved with lower overall acetone use (10:1 acetone to glycerol molar ratio and 50°C). Techno-economic analyses of the three solketal options were performed using Aspen (HYSYS), based on a fixed capacity of 100,000 te/y and 20-years lifetime. The techno-economic analyses showed that the net present values for the solketal process options were $707 M for the two-stage, $384 M for the one-stage at 6:1 acetone to glycerol molar ratio, and $703 M for the one-stage at 12:1 acetone to glycerol molar ratio. The break-even prices for these solketal processes were $2,058/ ton for the one-stage at 12:1 of acetone and two-stage and $2,088/ton for the one-stage at 6:1 of acetone, which is lower than the current price of solketal at $3,000/ton. The two-stage process was found to be the most effective method of glycerol valorization production to solketal.

Extractive recovery and valorisation of arsenic from contaminated soil through phytoremediation using Pteris cretica.

Contamination of ground water and soil by arsenic poses serious environmental challenges globally. A possible solution to this problem is through phytoremediation using hyper-accumulating plants. This study investigates phytoremediation of soil containing 200 ±â€¯3 mg kg-1 of arsenic using Pteris cretica ferns, and the strategies for arsenic extraction from the ferns biomass and subsequent conversions to valuable arsenic products. The Pteris cretica ferns achieved maximum arsenic accumulations of 4427 ±â€¯79 to 4875 ±â€¯96 mg of arsenic per kg dry biomass after 30 days. Extraction efficiencies of arsenic in the ferns fronds were 94.3 ±â€¯2.1% for ethanol-water (1:1 v/v), 81.5 ±â€¯3.2% for 1:1 (v/v) methanol-water, and 70.8 ±â€¯2.9% for water alone. Molybdic acid process was used to recover 90.8 ±â€¯5.3% of the arsenic, and 95.1 ±â€¯4.6% of the phosphorus in the biomass extract. Quantitative precipitation of Mg3(AsO4)2 and Mg3(PO4)2 occurred on treatment of the aqueous solutions of arsenic and phosphorus after stripping at pH of 8-10. The efficiencies of Mg3(AsO4)2 and Mg3(PO4)2 precipitation were 96 ±â€¯7.2% and 94 ±â€¯3.4%, respectively. Arsenic nanoparticles produced from the recovered Mg3(AsO4)2, using two-stage reduction process, had average particle diameters of 45.5 ±â€¯11.3 nm. These nanoparticles are potentially valuable for medical applications, while the Mg3(AsO4)2 could be converted to more valuable forms of arsenic or used as a pesticide, and the Mg3(PO4)2 in fertiliser. Recovery of these valuable products from phytoremediation biomass would incentivise and drive commercial industries' participation in remediation of contaminated lands.

NADPH Oxidase 5 Is a Pro-Contractile Nox Isoform and a Point of Cross-Talk for Calcium and Redox Signaling-Implications in Vascular Function.

BACKGROUND: NADPH Oxidase 5 (Nox5) is a calcium-sensitive superoxide-generating Nox. It is present in lower forms and higher mammals, but not in rodents. Nox5 is expressed in vascular cells, but the functional significance remains elusive. Given that contraction is controlled by calcium and reactive oxygen species, both associated with Nox5, we questioned the role of Nox5 in pro-contractile signaling and vascular function. METHODS AND RESULTS: Transgenic mice expressing human Nox5 in a vascular smooth muscle cell-specific manner (Nox5 mice) and Rhodnius prolixus, an arthropod model that expresses Nox5 endogenoulsy, were studied. Reactive oxygen species generation was increased systemically and in the vasculature and heart in Nox5 mice. In Nox5-expressing mice, agonist-induced vasoconstriction was exaggerated and endothelium-dependent vasorelaxation was impaired. Vascular structural and mechanical properties were not influenced by Nox5. Vascular contractile responses in Nox5 mice were normalized by N-acetylcysteine and inhibitors of calcium channels, calmodulin, and endoplasmic reticulum ryanodine receptors, but not by GKT137831 (Nox1/4 inhibitor). At the cellular level, vascular changes in Nox5 mice were associated with increased vascular smooth muscle cell [Ca2+]i, increased reactive oxygen species and nitrotyrosine levels, and hyperphosphorylation of pro-contractile signaling molecules MLC20 (myosin light chain 20) and MYPT1 (myosin phosphatase target subunit 1). Blood pressure was similar in wild-type and Nox5 mice. Nox5 did not amplify angiotensin II effects. In R. prolixus, gastrointestinal smooth muscle contraction was blunted by Nox5 silencing, but not by VAS2870 (Nox1/2/4 inhibitor). CONCLUSIONS: Nox5 is a pro-contractile Nox isoform important in redox-sensitive contraction. This involves calcium-calmodulin and endoplasmic reticulum-regulated mechanisms. Our findings define a novel function for vascular Nox5, linking calcium and reactive oxygen species to the pro-contractile molecular machinery in vascular smooth muscle cells.

Vascular Nox (NADPH Oxidase) Compartmentalization, Protein Hyperoxidation, and Endoplasmic Reticulum Stress Response in Hypertension.

Vascular Nox (NADPH oxidase)-derived reactive oxygen species and endoplasmic reticulum (ER) stress have been implicated in hypertension. However, relationships between these processes are unclear. We hypothesized that Nox isoforms localize in a subcellular compartment-specific manner, contributing to oxidative and ER stress, which influence the oxidative proteome and vascular function in hypertension. Nox compartmentalization (cell fractionation), O2- (lucigenin), H2O2 (amplex red), reversible protein oxidation (sulfenylation), irreversible protein oxidation (protein tyrosine phosphatase, peroxiredoxin oxidation), and ER stress (PERK [protein kinase RNA-like endoplasmic reticulum kinase], IRE1α [inositol-requiring enzyme 1], and phosphorylation/oxidation) were studied in spontaneously hypertensive rat (SHR) vascular smooth muscle cells (VSMCs). VSMC proliferation was measured by fluorescence-activated cell sorting, and vascular reactivity assessed in stroke-prone SHR arteries by myography. Noxs were downregulated by short interfering RNA and pharmacologically. In SHR, Noxs were localized in specific subcellular regions: Nox1 in plasma membrane and Nox4 in ER. In SHR, oxidative stress was associated with increased protein sulfenylation and hyperoxidation of protein tyrosine phosphatases and peroxiredoxins. Inhibition of Nox1 (NoxA1ds), Nox1/4 (GKT137831), and ER stress (4-phenylbutyric acid/tauroursodeoxycholic acid) normalized SHR vascular reactive oxygen species generation. GKT137831 reduced IRE1α sulfenylation and XBP1 (X-box binding protein 1) splicing in SHR. Increased VSMC proliferation in SHR was normalized by GKT137831, 4-phenylbutyric acid, and STF083010 (IRE1-XBP1 disruptor). Hypercontractility in the stroke-prone SHR was attenuated by 4-phenylbutyric acid. We demonstrate that protein hyperoxidation in hypertension is associated with oxidative and ER stress through upregulation of plasmalemmal-Nox1 and ER-Nox4. The IRE1-XBP1 pathway of the ER stress response is regulated by Nox4/reactive oxygen species and plays a role in the hyperproliferative VSMC phenotype in SHR. Our study highlights the importance of Nox subcellular compartmentalization and interplay between cytoplasmic reactive oxygen species and ER stress response, which contribute to the VSMC oxidative proteome and vascular dysfunction in hypertension.

Experimental Determination of Optimal Conditions for Reactive Coupling of Biodiesel Production With in situ Glycerol Carbonate Formation in a Triglyceride Transesterification Process.

This study investigated a reactive coupling to determine the optimal conditions for transesterification of rapeseed oil (RSO) to fatty acid methyl ester (FAME) and glycerol carbonate (GLC) in a one-step process, and at operating conditions which are compatible with current biodiesel industry. The reactive coupling process was studied by transesterification of RSO with various molar ratios of both methanol and dimethyl carbonate (DMC), using triazabicyclodecene (TBD) guanidine catalyst and reaction temperatures of 50-80°C. The optimal reaction conditions obtained, using a Design of Experiments approach, were a 2:1 methanol-to-RSO molar ratio and 3:1 DMC-to-RSO molar ratio at 60°C. The FAME and GLC conversions at the optimal conditions were 98.0 ± 1.5 and 90.1 ± 2.2%, respectively, after 1 h reaction time using the TBD guanidine catalyst. Increase in the DMC-to-RSO molar ratio from 3:1 to 6:1 slightly improved the GLC conversion to 94.1 ± 2.8% after 2 h, but this did not enhance the FAME conversion. Methanol substantially improved both FAME and GLC conversions at 1:1-2:1 methanol-to-RSO molar ratios and enhanced the GLC separation from the reaction mixture. It was observed that higher methanol molar ratios (>3:1) enhanced only FAME yields and resulted in lower GLC conversions due to reaction equilibrium limitations. At a 6:1 methanol-to-RSO molar ratio, 98.4% FAME and 73.3% GLC yields were obtained at 3:1 DMC-to-RSO molar ratio and 60°C. This study demonstrates that formation of low value crude glycerol can be reduced by over 90% compared to conventional biodiesel production, with significant conversion to GLC, a far more valuable product.

Serotonin Signaling Through the 5-HT1B Receptor and NADPH Oxidase 1 in Pulmonary Arterial Hypertension.

OBJECTIVE: Serotonin can induce human pulmonary artery smooth muscle cell (hPASMC) proliferation through reactive oxygen species (ROS), influencing the development of pulmonary arterial hypertension (PAH). We hypothesize that in PASMCs, serotonin induces oxidative stress through NADPH-oxidase-derived ROS generation and reduced Nrf-2 (nuclear factor [erythroid-derived 2]-like 2) antioxidant systems, promoting vascular injury. APPROACH AND RESULTS: HPASMCs from controls and PAH patients, and PASMCs from Nox1-/- mice, were stimulated with serotonin in the absence/presence of inhibitors of Src kinase, the 5-HT1B receptor, and NADPH oxidase 1 (Nox1). Markers of fibrosis were also determined. The pathophysiological significance of our findings was examined in vivo in serotonin transporter overexpressing female mice, a model of pulmonary hypertension. We confirmed thatserotonin increased superoxide and hydrogen peroxide production in these cells. For the first time, we show that serotonin increased oxidized protein tyrosine phosphatases and hyperoxidized peroxiredoxin and decreased Nrf-2 and catalase activity in hPASMCs. ROS generation was exaggerated and dependent on cellular Src-related kinase, 5-HT1B receptor, and the serotonin transporter in human pulmonary artery smooth muscle cells from PAH subjects. Proliferation and extracellular matrix remodeling were exaggerated in human pulmonary artery smooth muscle cells from PAH subjects and dependent on 5-HT1B receptor signaling and Nox1, confirmed in PASMCs from Nox1-/- mice. In serotonin transporter overexpressing mice, SB216641, a 5-HT1B receptor antagonist, prevented development of pulmonary hypertension in a ROS-dependent manner. CONCLUSIONS: Serotonin can induce cellular Src-related kinase-regulated Nox1-induced ROS and Nrf-2 dysregulation, contributing to increased post-translational oxidative modification of proteins and activation of redox-sensitive signaling pathways in hPASMCs, associated with mitogenic responses. 5-HT1B receptors contribute to experimental pulmonary hypertension by inducing lung ROS production. Our results suggest that 5-HT1B receptor-dependent cellular Src-related kinase-Nox1-pathways contribute to vascular remodeling in PAH.

Vascular dysfunction and fibrosis in stroke-prone spontaneously hypertensive rats: The aldosterone-mineralocorticoid receptor-Nox1 axis.

AIMS: We questioned whether aldosterone and oxidative stress play a role in vascular damage in severe hypertension and investigated the role of Nox1 in this process. MATERIALS AND METHODS: We studied mesenteric arteries, aortas and vascular smooth muscle cells (VSMC) from WKY and SHRSP rats. Vascular effects of eplerenone or canrenoic acid (CA) (mineralocorticoid receptor (MR) blockers), ML171 (Nox1 inhibitor) and EHT1864 (Rac1/2 inhibitor) were assessed. Nox1-knockout mice were also studied. Vessels and VSMCs were probed for Noxs, reactive oxygen species (ROS) and pro-fibrotic/inflammatory signaling. KEY FINDINGS: Blood pressure and plasma levels of aldosterone and galectin-3 were increased in SHRSP versus WKY. Acetylcholine-induced vasorelaxation was decreased (61% vs 115%) and phenylephrine-induced contraction increased in SHRSP versus WKY (Emax 132.8% vs 96.9%, p<0.05). Eplerenone, ML171 and EHT1864 attenuated hypercontractility in SHRSP. Vascular expression of collagen, fibronectin, TGFß, MCP-1, RANTES, MMP2, MMP9 and p66Shc was increased in SHRSP versus WKY. These changes were associated with increased ROS generation, 3-nitrotyrosine expression and Nox1 upregulation. Activation of vascular p66Shc and increased expression of Nox1 and collagen I were prevented by CA in SHRSP. Nox1 expression was increased in aldosterone-stimulated WKY VSMCs, an effect that was amplified in SHRSP VSMCs (5.2vs9.9 fold-increase). ML171 prevented aldosterone-induced VSMC Nox1-ROS production. Aldosterone increased vascular expression of fibronectin and PAI-1 in wild-type mice but not in Nox1-knockout mice. SIGNIFICANCE: Our findings suggest that aldosterone, which is increased in SHRSP, induces vascular damage through MR-Nox1-p66Shc-mediated processes that modulate pro-fibrotic and pro-inflammatory signaling pathways.

Applied in situ product recovery in ABE fermentation.

The production of biobutanol is hindered by the product's toxicity to the bacteria, which limits the productivity of the process. In situ product recovery of butanol can improve the productivity by removing the source of inhibition. This paper reviews in situ product recovery techniques applied to the acetone butanol ethanol fermentation in a stirred tank reactor. Methods of in situ recovery include gas stripping, vacuum fermentation, pervaporation, liquid-liquid extraction, perstraction, and adsorption, all of which have been investigated for the acetone, butanol, and ethanol fermentation. All techniques have shown an improvement in substrate utilization, yield, productivity or both. Different fermentation modes favored different techniques. For batch processing gas stripping and pervaporation were most favorable, but in fed-batch fermentations gas stripping and adsorption were most promising. During continuous processing perstraction appeared to offer the best improvement. The use of hybrid techniques can increase the final product concentration beyond that of single-stage techniques. Therefore, the selection of an in situ product recovery technique would require comparable information on the energy demand and economics of the process. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:563-579, 2017.

A comparison of the energy use of in situ product recovery techniques for the Acetone Butanol Ethanol fermentation.

The productivity of the Acetone Butanol Ethanol (ABE) fermentation can be significantly increased by application of various in situ product recovery (ISPR) techniques. There are numerous technically viable processes, but it is not clear which is the most economically viable in practice. There is little available information about the energy requirements and economics of ISPR for the ABE fermentation. This work compares various ISPR techniques based on UniSim process simulations of the ABE fermentation. The simulations provide information on the process energy and separation efficiency, which is fed into an economic assessment. Perstraction was the only technique to reduce the energy demand below that of a batch process, by approximately 5%. Perstraction also had the highest profit increase over a batch process, by 175%. However, perstraction is an immature technology, so would need significant development before being integrated to an industrial process.