Enhanced product recovery from glycerol fermentation into 3-carbon compounds in a bioelectrochemical system combined with in situ extraction

Given the large amount of crude glycerol formed as a by-product in the biodiesel industries and the concomitant decrease in its overall market price, there is a need to add extra value to this biorefinery side stream. Upgrading can be achieved by new biotechnologies dealing with recovery and conversion of glycerol present in wastewaters into value-added products, aiming at a zero-waste policy and developing an economically viable process. In microbial bioelectrochemical systems (BESs), the mixed microbial community growing on the cathode can convert glycerol reductively to 1,3-propanediol (1,3-PDO). However, the product yield is rather limited in BESs compared with classic fermentation processes, and the synthesis of side-products, resulting from oxidation of glycerol, such as organic acids, represents a major burden for recovery of 1,3-PDO. Here, we show that the use of an enriched mixed-microbial community of glycerol degraders and in situ extraction of organic acids positively impacts 1,3-PDO yield and allows additional recovery of propionate from glycerol. We report the highest production yield achieved (0.72 mol1,3-PDO mol−1glycerol) in electricity-driven 1,3-PDO biosynthesis from raw glycerol, which is very close to the 1,3-PDO yield reported thus far for a mixed-microbial culture-based glycerol fermentation process. We also present a combined approach for 1,3-PDO production and propionate extraction in a single three chamber reactor system, which leads to recovery of additional 3-carbon compounds in BESs. This opens up further opportunities for an economical upgrading of biodiesel refinery side or waste streams

Continuous long-term electricity-driven bioproduction of carboxylates and isopropanol from CO2 with a mixed microbial community

Electricity-driven bioproduction processes such as microbial electrosynthesis enable converting CO2 and organic feedstocks into target chemicals with minimal addition of external chemicals. Bioelectrochemical CO2 conversion to (mainly) acetate has mostly been demonstrated in batch processes. Continuous reactor operation and the operational parameters associated with it have received limited attention. Here, we demonstrate that improving bioelectrochemical reactor design to a higher cathode surface to volume ratio results in an enhanced acetate titer; 5.7 +/- 0.74 g L-1 (11.5 +/- 6.6 g m(-2) d(-1)) in galvanostastically controlled (-5 A m(-2) (cathode)) batch reactors with a mixed microbial community. A long-term and stable bioproduction process could be established in which hydraulic residence time (HRT) affected the product patterns as well as the acetate production rate, up to 21 g m(-2) d(-1) for an HRT of 3.3d (63% coulombic efficiency) was achieved; the highest reported thus far in a continuous process. The specific energy input per kilogram of acetic acid produced during batch and continuous processes (HRT: 3.3d) was 29 +/- 0.7 and 16 +/- 1.3 kWhel kg(-1), respectively. Butyrate and isopropanol were the other major biochemicals produced at maximum rates of 3.7 and 3.3 g m(-2) d(-1) (18.6% and 21.8% of the electrons, respectively) leading to titers of 0.67 and 0.82 g L-1 during the continuous process. This is the first report on the production of a secondary alcohol (isopropanol), using a mixed culture, in CO2 fed systems. The product ratios between these organics could be steered based on operational pH and HRTs. Operating reactors at an HRT of 5 d at pH 5 led to stable production of butyrate (1.9 +/- 0.6 g m(-2) d(-1)) and isopropanol (1.17 +/- 0.34 g m(-2) d(-1)). Cyclic voltammetry suggested an "ennoblement" of the cathode over time, shifting the onset for reductive current by more than 150 mV. Microbial community analysis revealed Acetobacterium as the main bacterial group involved in CO2 reduction to acetate, and the presence of diverse bacterial groups in response to different operational conditions

Continuous and long-term electricity-driven production of acetate from CO2 using a mixed microbial community

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Electrical current is more than hydrogen during microbial electrosynthesis and electrofermentation

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Assessment of carbon loss related to Soil loss in the tropical watershed of Maharashtra, India

Soil carbon pools have a significant impact on the global carbon cycle and soil erosion caused by natural or human activities is one of the main drivers of changes in soil carbon sequestration. The present study aimed to estimate the carbon loss associated with soil loss in the watershed using remote sensing and GIS techniques. The study was carried out at the Central MPKV Campus Watershed, Rahuri, located in the rain shadow region of the Maharashtra state, India. The soil loss from the watershed was estimated using USLE model. The soil loss and carbon loss from the watershed were estimated before the implementation of conservation measures and after the implementation of conservation measures. It was found that the average annual soil loss from the watershed before and after conservation measures was 18.68 t/ha/yr and 9.41 t/ha/yr, respectively. Carbon loss was determined by soil loss rate, organic carbon content and the carbon enrichment ratio. The carbon loss from the watershed before and after conservation measures was 348.71 kgC/ha/yr and 205.52 kgC/ha/yr. The findings revealed that soil and carbon erosion was very severe on steep slopes without conservation measures and with limited vegetation cover. It was found that by reducing the carbon loss associated with soil loss, soil conservation measures not only aid in the conservation of natural resources but also serve as a climate change mitigation measure

Calibration of the CMS hadron calorimeters using proton-proton collision data at root s=13 TeV

Methods are presented for calibrating the hadron calorimeter system of theCMSetector at the LHC. The hadron calorimeters of the CMS experiment are sampling calorimeters of brass and scintillator, and are in the form of one central detector and two endcaps. These calorimeters cover pseudorapidities vertical bar eta vertical bar ee data. The energy scale of the outer calorimeters has been determined with test beam data and is confirmed through data with high transverse momentum jets. In this paper, we present the details of the calibration methods and accuracy.Peer reviewe

Global, regional, and national burden of disorders affecting the nervous system, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BackgroundDisorders affecting the nervous system are diverse and include neurodevelopmental disorders, late-life neurodegeneration, and newly emergent conditions, such as cognitive impairment following COVID-19. Previous publications from the Global Burden of Disease, Injuries, and Risk Factor Study estimated the burden of 15 neurological conditions in 2015 and 2016, but these analyses did not include neurodevelopmental disorders, as defined by the International Classification of Diseases (ICD)-11, or a subset of cases of congenital, neonatal, and infectious conditions that cause neurological damage. Here, we estimate nervous system health loss caused by 37 unique conditions and their associated risk factors globally, regionally, and nationally from 1990 to 2021.MethodsWe estimated mortality, prevalence, years lived with disability (YLDs), years of life lost (YLLs), and disability-adjusted life-years (DALYs), with corresponding 95% uncertainty intervals (UIs), by age and sex in 204 countries and territories, from 1990 to 2021. We included morbidity and deaths due to neurological conditions, for which health loss is directly due to damage to the CNS or peripheral nervous system. We also isolated neurological health loss from conditions for which nervous system morbidity is a consequence, but not the primary feature, including a subset of congenital conditions (ie, chromosomal anomalies and congenital birth defects), neonatal conditions (ie, jaundice, preterm birth, and sepsis), infectious diseases (ie, COVID-19, cystic echinococcosis, malaria, syphilis, and Zika virus disease), and diabetic neuropathy. By conducting a sequela-level analysis of the health outcomes for these conditions, only cases where nervous system damage occurred were included, and YLDs were recalculated to isolate the non-fatal burden directly attributable to nervous system health loss. A comorbidity correction was used to calculate total prevalence of all conditions that affect the nervous system combined.FindingsGlobally, the 37 conditions affecting the nervous system were collectively ranked as the leading group cause of DALYs in 2021 (443 million, 95% UI 378–521), affecting 3·40 billion (3·20–3·62) individuals (43·1%, 40·5–45·9 of the global population); global DALY counts attributed to these conditions increased by 18·2% (8·7–26·7) between 1990 and 2021. Age-standardised rates of deaths per 100 000 people attributed to these conditions decreased from 1990 to 2021 by 33·6% (27·6–38·8), and age-standardised rates of DALYs attributed to these conditions decreased by 27·0% (21·5–32·4). Age-standardised prevalence was almost stable, with a change of 1·5% (0·7–2·4). The ten conditions with the highest age-standardised DALYs in 2021 were stroke, neonatal encephalopathy, migraine, Alzheimer's disease and other dementias, diabetic neuropathy, meningitis, epilepsy, neurological complications due to preterm birth, autism spectrum disorder, and nervous system cancer.InterpretationAs the leading cause of overall disease burden in the world, with increasing global DALY counts, effective prevention, treatment, and rehabilitation strategies for disorders affecting the nervous system are needed

Global burden of 288 causes of death and life expectancy decomposition in 204 countries and territories and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

BACKGROUND Regular, detailed reporting on population health by underlying cause of death is fundamental for public health decision making. Cause-specific estimates of mortality and the subsequent effects on life expectancy worldwide are valuable metrics to gauge progress in reducing mortality rates. These estimates are particularly important following large-scale mortality spikes, such as the COVID-19 pandemic. When systematically analysed, mortality rates and life expectancy allow comparisons of the consequences of causes of death globally and over time, providing a nuanced understanding of the effect of these causes on global populations. METHODS The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 cause-of-death analysis estimated mortality and years of life lost (YLLs) from 288 causes of death by age-sex-location-year in 204 countries and territories and 811 subnational locations for each year from 1990 until 2021. The analysis used 56 604 data sources, including data from vital registration and verbal autopsy as well as surveys, censuses, surveillance systems, and cancer registries, among others. As with previous GBD rounds, cause-specific death rates for most causes were estimated using the Cause of Death Ensemble model-a modelling tool developed for GBD to assess the out-of-sample predictive validity of different statistical models and covariate permutations and combine those results to produce cause-specific mortality estimates-with alternative strategies adapted to model causes with insufficient data, substantial changes in reporting over the study period, or unusual epidemiology. YLLs were computed as the product of the number of deaths for each cause-age-sex-location-year and the standard life expectancy at each age. As part of the modelling process, uncertainty intervals (UIs) were generated using the 2·5th and 97·5th percentiles from a 1000-draw distribution for each metric. We decomposed life expectancy by cause of death, location, and year to show cause-specific effects on life expectancy from 1990 to 2021. We also used the coefficient of variation and the fraction of population affected by 90% of deaths to highlight concentrations of mortality. Findings are reported in counts and age-standardised rates. Methodological improvements for cause-of-death estimates in GBD 2021 include the expansion of under-5-years age group to include four new age groups, enhanced methods to account for stochastic variation of sparse data, and the inclusion of COVID-19 and other pandemic-related mortality-which includes excess mortality associated with the pandemic, excluding COVID-19, lower respiratory infections, measles, malaria, and pertussis. For this analysis, 199 new country-years of vital registration cause-of-death data, 5 country-years of surveillance data, 21 country-years of verbal autopsy data, and 94 country-years of other data types were added to those used in previous GBD rounds. FINDINGS The leading causes of age-standardised deaths globally were the same in 2019 as they were in 1990; in descending order, these were, ischaemic heart disease, stroke, chronic obstructive pulmonary disease, and lower respiratory infections. In 2021, however, COVID-19 replaced stroke as the second-leading age-standardised cause of death, with 94·0 deaths (95% UI 89·2-100·0) per 100 000 population. The COVID-19 pandemic shifted the rankings of the leading five causes, lowering stroke to the third-leading and chronic obstructive pulmonary disease to the fourth-leading position. In 2021, the highest age-standardised death rates from COVID-19 occurred in sub-Saharan Africa (271·0 deaths [250·1-290·7] per 100 000 population) and Latin America and the Caribbean (195·4 deaths [182·1-211·4] per 100 000 population). The lowest age-standardised death rates from COVID-19 were in the high-income super-region (48·1 deaths [47·4-48·8] per 100 000 population) and southeast Asia, east Asia, and Oceania (23·2 deaths [16·3-37·2] per 100 000 population). Globally, life expectancy steadily improved between 1990 and 2019 for 18 of the 22 investigated causes. Decomposition of global and regional life expectancy showed the positive effect that reductions in deaths from enteric infections, lower respiratory infections, stroke, and neonatal deaths, among others have contributed to improved survival over the study period. However, a net reduction of 1·6 years occurred in global life expectancy between 2019 and 2021, primarily due to increased death rates from COVID-19 and other pandemic-related mortality. Life expectancy was highly variable between super-regions over the study period, with southeast Asia, east Asia, and Oceania gaining 8·3 years (6·7-9·9) overall, while having the smallest reduction in life expectancy due to COVID-19 (0·4 years). The largest reduction in life expectancy due to COVID-19 occurred in Latin America and the Caribbean (3·6 years). Additionally, 53 of the 288 causes of death were highly concentrated in locations with less than 50% of the global population as of 2021, and these causes of death became progressively more concentrated since 1990, when only 44 causes showed this pattern. The concentration phenomenon is discussed heuristically with respect to enteric and lower respiratory infections, malaria, HIV/AIDS, neonatal disorders, tuberculosis, and measles. INTERPRETATION Long-standing gains in life expectancy and reductions in many of the leading causes of death have been disrupted by the COVID-19 pandemic, the adverse effects of which were spread unevenly among populations. Despite the pandemic, there has been continued progress in combatting several notable causes of death, leading to improved global life expectancy over the study period. Each of the seven GBD super-regions showed an overall improvement from 1990 and 2021, obscuring the negative effect in the years of the pandemic. Additionally, our findings regarding regional variation in causes of death driving increases in life expectancy hold clear policy utility. Analyses of shifting mortality trends reveal that several causes, once widespread globally, are now increasingly concentrated geographically. These changes in mortality concentration, alongside further investigation of changing risks, interventions, and relevant policy, present an important opportunity to deepen our understanding of mortality-reduction strategies. Examining patterns in mortality concentration might reveal areas where successful public health interventions have been implemented. Translating these successes to locations where certain causes of death remain entrenched can inform policies that work to improve life expectancy for people everywhere. FUNDING Bill & Melinda Gates Foundation

Engineering electrodes for microbial electrocatalysis

Microbial electrocatalysis refers to the use of microorganisms to catalyze electrode reactions. Many processes have been developed on this principle, ranging from power generation to CO2 conversion using bioelectrochemical systems. The nature of the interface between the microorganisms and the electrodes determines the functioning and efficiency of these systems. This interface can be manipulated in terms of chemical and topographical features to better understand the interaction at nanometer and micrometer scales. Here we discuss how the electrode surface topography and chemistry impact the microorganism-electrode interaction both for direct and indirect electron transfer mechanisms. It appears that composite materials that combine high conductivity with excellent biocompatibility are most attractive towards application. In most cases this implies a combination of a metallic backbone with a carbon coating with a defined topography and chemistry

Microbial electrosynthesis with an enriched mixed homoacetogenic culture

The bioproduction of chemicals such as acetate from CO2 with mixed microbial inoculum sources is affected by methanogens that compete with the acetogenic bacteria for electron donors. The practice of using methanogen inhibitors in the bioelectrochemical systems (BESs) is not a sustainable approach. A prior enrichment of the homoacetogens and the use of such enriched culture can be considered as a better strategy. Herein, an enriched homoacetogenic culture is under investigation as an inoculum for microbial electrosynthesis (MES) starting from CO2. Initial observations revealed the production of acetate (up to 300 mg/L) and other volatile fatty acids (VFAs) such as formate, propionate and butyrate in low concentration in fed-batch BES reactors. Methane production was suppressed throughout the experiment. Further validation of the observations, performance improvement, efficiency tests, electron uptake mechanisms and microbial community analysis are the objectives of ongoing work