Whole-organ transdermal photobiomodulation (PBM) of COVID-19: A 50-patient case study.

A nonrandomized 50-person case study of COVID-19-positive patients was conducted employing (for the first time) a regimen of whole-organ deep-tissue transdermal dynamic photobiomodulation (PBM) as a primary (or exclusive) therapeutic modality in the treatment of coronavirus. Therapy sessions comprised algorithmically alternating red (650 nm) and near-infrared (NIR; 850 nm) LEDs with an average irradiance of 11 mW/cm dynamically sequenced at multiple pulse frequencies. Delivered via 3D bendable polymeric pads maintaining orthogonal optical incidence to body contours over 1,000 cm , a single 84-minute session concurrently delivered 20 kJ to the sinuses and 15 kJ to each lung at skin temperatures below 42°C.

This time is indeed different: A study on global market reactions to public health crisis.

This paper studies the differences in stock market reactions to the same kind of disease-related news by analyzing abnormal returns of global stock markets during Public Health Risk Emergency of International Concern (PHEIC) announcements. Drawing the data from 26 stock market indices over the period from 22 April 2008 to 12 March 2020, we compare stock market reactions to all six PHEIC announcements made by the World Health Organization since 2009. Although the PHEIC announcements can be categorized as the same type of event, we found no consistent patterns in market reactions.

Assessing pretreatment reactor scaling through empirical analysis.

Background: Pretreatment is a critical step in the biochemical conversion of lignocellulosic biomass to fuels and chemicals. Due to the complexity of the physicochemical transformations involved, predictively scaling up technology from bench- to pilot-scale is difficult. This study examines how pretreatment effectiveness under nominally similar reaction conditions is influenced by pretreatment reactor design and scale using four different pretreatment reaction systems ranging from a 3 g batch reactor to a 10 dry-ton/days continuous reactor.

Accounting for all sugars produced during integrated production of ethanol from lignocellulosic biomass.

Accurate mass balance and conversion data from integrated operation is needed to fully elucidate the economics of biofuel production processes. This study explored integrated conversion of corn stover to ethanol and highlights techniques for accurate yield calculations. Acid pretreated corn stover (PCS) produced in a pilot-scale reactor was enzymatically hydrolyzed and the resulting sugars were fermented to ethanol by the glucose-xylose fermenting bacteria, Zymomonas mobilis 8b.

Performance and techno-economic assessment of several solid-liquid separation technologies for processing dilute-acid pretreated corn stover.

Solid-liquid separation of pretreated lignocellulosic biomass slurries is a critical unit operation employed in several different processes for production of fuels and chemicals. An effective separation process achieves good recovery of solute (sugars) and efficient dewatering of the biomass slurry. Dilute acid pretreated corn stover slurries were subjected to pressure and vacuum filtration and basket centrifugation to evaluate the technical and economic merits of these technologies.

Characterization of pilot-scale dilute acid pretreatment performance using deacetylated corn stover.

Background: Dilute acid pretreatment is a promising process technology for the deconstruction of low-lignin lignocellulosic biomass, capable of producing high yields of hemicellulosic sugars and enhancing enzymatic yields of glucose as part of a biomass-to-biofuels process. However, while it has been extensively studied, most work has historically been conducted at relatively high acid concentrations of 1 - 4% (weight/weight). Reducing the effective acid loading in pretreatment has the potential to reduce chemical costs both for pretreatment and subsequent neutralization.

Degradation of carbohydrates during dilute sulfuric acid pretreatment can interfere with lignin measurements in solid residues.

The lignin content measured after dilute sulfuric acid pretreatment of corn stover indicates more lignin than could be accounted for on the basis of the untreated corn stover lignin content. This phenomenon was investigated using a combination of (13)C cross-polarization/magic-angle spinning (CP/MAS) solid-state nuclear magnetic resonance (NMR) spectroscopy and lignin removal using acid chlorite bleaching. Only minimal contamination with carbohydrates and proteins was observed in the pretreated corn stover.

Conversion of residual organics in corn stover-derived biorefinery stream to bioenergy via a microbial fuel cell.

A biorefinery process typically uses about 4-10 times more water than the amount of biofuel generated. The wastewater produced in a biorefinery process contains residual sugars, 5-furfural, phenolics, and other pretreatment and fermentation byproducts. Treatment of the wastewater can reduce the need for fresh water and potentially add to the environmental benefits of the process.

Membrane extraction for detoxification of biomass hydrolysates.

Membrane extraction was used for the removal of sulfuric acid, acetic acid, 5-hydroxymethyl furfural and furfural from corn stover hydrolyzed with dilute sulfuric acid. Microporous polypropylene hollow fiber membranes were used. The organic extractant consisted of 15% Alamine 336 in: octanol, a 50:50 mixture of oleyl alcohol:octanol or oleyl alcohol.

Fermentation of reactive-membrane-extracted and ammonium-hydroxide-conditioned dilute-acid-pretreated corn stover.

Acid-pretreated biomass contains various compounds (acetic acid, etc.) that are inhibitory to fermentative microorganisms. Removing or deactivating these compounds using detoxification methods such as overliming or ammonium hydroxide conditioning (AHC) improves sugar-to-ethanol yields.

Mass spectral analyses of corn stover prehydrolysates to assess conditioning processes.

Flow injection electrospray (FIE) and LC-tandem mass spectrometry techniques were used to characterize corn stover acid hydrolysates before and after overliming and ammonia conditioning steps. Analyses were performed on samples without fractionation (dilution only) in an effort provide an inventory of ionizable substances. Statistical evaluation of the results indicates that the ammonia-treated and crude hydrolysates were more similar to one another than any other pairing, with conditioning leading to a decrease in malate levels.

Economic impact of total solids loading on enzymatic hydrolysis of dilute acid pretreated corn stover.

In process integration studies of the biomass-to-ethanol conversion process, it is necessary to understand how cellulose conversion yields vary as a function of solids and enzyme loading and other key operating variables. The impact of solids loading on enzymatic cellulose hydrolysis of dilute acid pretreated corn stover slurry was determined using an experimental response surface design methodology. From the experimental work, an empirical correlation was obtained that expresses monomeric glucose yield from enzymatic cellulose hydrolysis as a function of solids loading, enzyme loading, and temperature.

Conditioning of dilute-acid pretreated corn stover hydrolysate liquors by treatment with lime or ammonium hydroxide to improve conversion of sugars to ethanol.

Dilute-acid pretreatment of lignocellulosic biomass enhances the ability of enzymes to hydrolyze cellulose to glucose, but produces many toxic compounds that inhibit fermentation of sugars to ethanol. The objective of this study was to compare the effectiveness of treating hydrolysate liquor with Ca(OH)2 and NH4OH for improving ethanol yields. Corn stover was pretreated in a pilot-scale reactor and then the liquor fraction (hydrolysate) was extracted and treated with various amounts of Ca(OH)2 or NH4OH at several temperatures.

Impact of recycling stillage on conversion of dilute sulfuric acid pretreated corn stover to ethanol.

Both the current corn starch to ethanol industry and the emerging lignocellulosic biofuels industry view recycling of spent fermentation broth or stillage as a method to reduce fresh water use. The objective of this study was to understand the impact of recycling stillage on conversion of corn stover to ethanol. Sugars in a dilute-acid pretreated corn stover hydrolysate were fermented to ethanol by the glucose-xylose fermenting bacteria Zymomonas mobilis 8b.

An economic comparison of different fermentation configurations to convert corn stover to ethanol using Z. mobilis and Saccharomyces.

Numerous routes are being explored to lower the cost of cellulosic ethanol production and enable large-scale production. One critical area is the development of robust cofermentative organisms to convert the multiple, mixed sugars found in biomass feedstocks to ethanol at high yields and titers without the need for processing to remove inhibitors. Until such microorganisms are commercialized, the challenge is to design processes that exploit the current microorganisms' strengths.

Impact of corn stover composition on hemicellulose conversion during dilute acid pretreatment and enzymatic cellulose digestibility of the pretreated solids.

This study assessed the impact of corn stover compositional variability on xylose conversion yields during dilute acid pretreatment and on enzymatic cellulose digestibility of the resulting pretreated solids. Seven compositionally-different stovers obtained from various locations throughout the United States were pretreated at three different conditions in triplicate in a pilot-scale continuous reactor. At the same pretreatment severity, a 2-fold increase in monomeric xylose yield and a 1.

Comparative study of corn stover pretreated by dilute acid and cellulose solvent-based lignocellulose fractionation: Enzymatic hydrolysis, supramolecular structure, and substrate accessibility.

Liberation of fermentable sugars from recalcitrant biomass is among the most costly steps for emerging cellulosic ethanol production. Here we compared two pretreatment methods (dilute acid, DA, and cellulose solvent and organic solvent lignocellulose fractionation, COSLIF) for corn stover. At a high cellulase loading [15 filter paper units (FPUs) or 12.

Rheology of corn stover slurries at high solids concentrations--effects of saccharification and particle size.

The rheological characteristics of untreated and dilute acid pretreated corn stover (CS) slurries at high solids concentrations were studied under continuous shear using plate-plate type measurements. Slurry rheological behavior was examined as a function of insoluble solids concentration (10-40%), extent of pretreatment (0-75% removal of xylan) and particle size (-20 and -80 mesh). Results show that CS slurries exhibit shear-thinning behavior describable using a Casson model.

Soluble and insoluble solids contributions to high-solids enzymatic hydrolysis of lignocellulose.

The rates and extents of enzymatic cellulose hydrolysis of dilute acid pretreated corn stover (PCS) decline with increasing slurry concentration. However, mass transfer limitations are not apparent until insoluble solids concentrations approach 20% w/w, indicating that inhibition of enzyme hydrolysis at lower solids concentrations is primarily due to soluble components. Consequently, the inhibitory effects of pH-adjusted pretreatment liquor on the enzymatic hydrolysis of PCS were investigated.

Model-based fed-batch for high-solids enzymatic cellulose hydrolysis.

While many kinetic models have been developed for the enzymatic hydrolysis of cellulose, few have been extensively applied for process design, optimization, or control. High-solids operation of the enzymatic hydrolysis of lignocellulose is motivated by both its operation decreasing capital costs and increasing product concentration and hence separation costs. This work utilizes both insights obtained from experimental work and kinetic modeling to develop an optimization strategy for cellulose saccharification at insoluble solids levels greater than 15% (w/w), where mixing in stirred tank reactors (STRs) becomes problematic.

Modeling sucrose hydrolysis in dilute sulfuric acid solutions at pretreatment conditions for lignocellulosic biomass.

Agricultural and herbaceous feedstocks may contain appreciable levels of sucrose. The goal of this study was to evaluate the survivability of sucrose and its hydrolysis products, fructose and glucose, during dilute sulfuric acid processing at conditions typically used to pretreat lignocellulose biomass. Solutions containing 25g/l sucrose with 0.

Porosity and its effect on the digestibility of dilute sulfuric acid pretreated corn stover.

Enzyme accessibility has been proposed as a limiting factor in the enzymatic conversion of the cellulose in biomass to glucose. Prior work has shown a strong correlation between porosity, measured as the change in the volume of pores accessible to a cellulase-sized molecule, and the initial digestibility of biomass pretreated by various methods. The goal of this work was to determine if porosity was one of the factors governing the overall enzymatic digestibility of the cellulose in dilute acid pretreated biomass.

Contaminant occurrence, identification and control in a pilot-scale corn fiber to ethanol conversion process.

While interest in bioethanol production from lignocellulosic feedstocks is increasing, there is still relatively little pilot-plant data and operating experience available for this emerging industry. A series of batch and continuous fermentation runs were performed in a pilot-plant, some lasting up to six weeks, in which corn fiber-derived sugars were fermented to ethanol using glucose-fermenting and recombinant glucose/xylose-fermenting yeasts. However, contamination by Lactobacillus bacteria was a common occurrence during these runs.

Methodological analysis for determination of enzymatic digestibility of cellulosic materials.

Accurate measurement of enzymatic cellulose digestibility (X) is important in evaluating the efficiency of lignocellulose pretreatment technologies, assessing the performance of reconstituted cellulase mixtures, and conducting economic analysis for biorefinery processes. We analyzed the effect of sugars contained in enzymes solutions, usually added as a preservative, and random measurement errors on the accuracy of X calculated by various methods. The analysis suggests that exogenous sugars at levels measured in several commercial enzyme preparations significantly bias the results and that this error should be minimized by accounting for these sugars in the calculation of X.