Publications by authors named "David Bressler"

Rhodosporidium toruloides has emerged as a prominent candidate for producing single-cell oil from cost-effective feedstocks. In this study, the capability of R. toruloides to produce punicic acid (PuA), a representative plant unusual fatty acid, was investigated.

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Introduction: The African Center for Integrated Laboratory Training (ACILT) in Johannesburg, South Africa offered a laboratory biosafety program to improve laboratory biosafety practices in 22 President's Emergency Plan for AIDS Relief (PEPFAR) supported countries. This manuscript evaluates the transference of newly gained knowledge and skills to the participants' place of employment for HIV and TB diagnostic laboratory programs. It also serves as a follow-on to a previously published manuscript that measured training effectiveness for all courses offered at ACILT.

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The high sulfuric acid concentration used in the hydrolysis of cellulose to isolate cellulose nanocrystals (CNCs) leads to low yields due to the dissolution of both amorphous and semi-crystalline cellulose. The present study explored the use of steam explosion pretreatment before acid hydrolysis to enhance the crystallization of semi-crystalline/ non-crystalline cellulose and generating new CNC precursors with poplar wood as feedstock. The crystallinity of steam exploded poplar wood increased 1.

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Bioethanol is a renewable fuel widely used in road transportation and is generally regarded as a clean energy source. Although fermentation is one of the major processes in bioethanol production, studies on improving its efficiency through operational design are limited, especially compared to other steps (pretreatment and hydrolysis/saccharification). In this study, two adapted feeding strategies, in which feed medium addition (sugar delivery) was adjusted to increase the supply of fermentable sugar, were developed to improve ethanol productivity in 5-L fed-batch fermentation by .

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Strict bans on specific risk materials (SRMs) are in place to prevent the spread of bovine spongiform encephalopathy (BSE). SRMs are characterized as tissues in cattle where misfolded proteins, the potential source of BSE infection, are concentrated. As a result of these bans, SRMs must be strictly isolated and disposed of, resulting in great costs for rendering companies.

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The expanding use of fossil fuels has caused concern in terms of both energy security and environmental issues. Therefore, attempts have been made worldwide to promote the development of renewable energy sources, among which biofuel is especially attractive. Compared to other biofuels, lipid-derived biofuels have a higher energy density and better compatibility with existing infrastructure, and their performance can be readily improved by adjusting the chemical composition of lipid feedstocks.

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Reclamation of tailings ponds is a critical issue for the oil industry. After years of consolidation, the slurry in tailings ponds, also known as fluid fine tailings, is mainly comprised of residual bitumen, water, and fine clay particles. To reclaim the lands that these ponds occupy, separation of the solid particles from the liquid phase is necessary to facilitate water removal and recycling.

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Multichannel electrode arrays offer insight into the working brain and serve to elucidate neural processes at the single-cell and circuit levels. Development of these tools is crucial for understanding complex behaviors and cognition and for advancing clinical applications. However, it remains a challenge to densely record from cell populations stably and continuously over long time periods.

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Fluid fine tailings are produced in huge quantities by Canada's mined oil sands industry. Due to the high colloidal stability of the contained fine solids, settling of fluid fine tailings can take hundreds of years, making the entrapped water unavailable and posing challenges to public health and the environment. This study focuses on developing value-added aggregation agents from specified risk materials (SRM), a waste protein stream from slaughterhouse industries, to achieve an improved separation of fluid fine tailings into free water and solids.

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A promising approach to help offset production costs for the cellulosic ethanol industry is to improve ethanol productivity while simultaneously generating value-added by-products. This study reports integration of an advanced fermentation approach (self-cycling fermentation) with the production of cellulose nanocrystals. Specifically, wood pulp was enzymatically hydrolyzed to yield dissolved sugars, which were fed to a self-cycling fermentation system for ethanol production, and residual solids were used for cellulose nanocrystals production via acid hydrolysis.

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Abstract: The accumulating volumes of biosolids in lagoons worldwide have intensified the need to develop innovative wastewater treatment strategies. Here, we provide proof-of-concept for the incorporation of biosolids into the hydrolysis step of a two-step thermal conversion of lipids for production of renewable hydrocarbons, which can be utilized as renewable fuels. Brown grease was hydrolysed with biosolids or water at 260-280 °C for 60 min at a mass ratio of 1:1 feed to water or biosolids.

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Hydrothermal treatment of wood pulp at 150-225°C prior to acid hydrolysis was investigated in the context of isolating cellulose nanocrystals (CNCs). The objective was 2-folds as follows: (a) generating furfural as a value-added co-product; and (b) concentrating and forming new CNC precursors through thermal re-orientation of para-crystalline cellulose chains that will in turn improve CNC recovery and yield. Furfural yields up to 19 and 21% xylan conversion were obtained at 200 and 225°C hydrothermal treatments, respectively.

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The escalating generation of biosolids and increasing regulations regarding their safe handling and disposal have created a great environmental challenge. Recently, biosolids have been incorporated into the hydrolysis step of a two-step thermal lipid conversion process to act as water replacement in the production of renewable chemicals and fuels. Here, the hexane extract recovered from hydrolysis of biosolids, lipids from brown grease hydrolyzed using either water (control) or biosolids as a water replacement, was pyrolyzed at 410-450 °C for 2 h.

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Isolation of fiber concentrate enriched in β-glucan from barley flour via air currents assisted particle separation (ACAPS) generates an underutilized by-product stream, starch concentrate. Since barley starch concentrate (BSC) is depleted in soluble fibre, we examined the enzyme requirements for its hydrolysis and subsequent fermentation. Lower doses of a common raw starch hydrolyzing enzyme (STARGEN™ 002) effectively hydrolyzed BSC, achieving similar hydrolysis kinetics to the wheat benchmark.

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Background: The growth of the cellulosic ethanol industry is currently impeded by high production costs. One possible solution is to improve the performance of fermentation itself, which has great potential to improve the economics of the entire production process. Here, we demonstrated significantly improved productivity through application of an advanced fermentation approach, named self-cycling fermentation (SCF), for cellulosic ethanol production.

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Spatial attention improves performance on visual tasks, increases neural responses to attended stimuli, and reduces correlated noise in visual cortical neurons. In addition to being visually responsive, many retinotopic visual cortical areas exhibit very slow (<0.1 Hz) endogenous fluctuations in functional magnetic resonance imaging signals.

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In this study, fermentable sugars and cellulose nanocrystals (CNCs) were co-produced from endoglucanase treatment of wood pulp, followed by acid hydrolysis. Enzymatic hydrolysis was performed using two endoglucanases differentiated by the presence or absence of a cellulose-binding domain (CBD). The enzyme with an intact CBD gave the higher glucan conversion (up to 14.

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Integrating enzymatic treatment and acid hydrolysis potentially improves the economics of cellulose nanocrystal (CNC) production and demonstrates a sustainable cellulosic ethanol co-generation strategy. In this study, the effect of enzymatic treatment on filter paper and wood pulp fibers, and CNCs generated via subsequent acid hydrolysis were assessed. Characterization was performed using a pulp quality monitoring system, scanning and transmission electron microscopies, dynamic light scattering, X-ray diffraction, and thermogravimetric analysis.

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Although the improved dewaterability and digestibility of primary biosolids subjected to thermal hydrolysis has been studied for decades, there are a surprisingly small number of studies exploring the use of this thermal treatment for digested biosolids that are typically left to settle in large settling lagoons. This is likely because of the high capital and operating costs associated with thermal hydrolysis, coupled with the limited applications and value of the resulting products. However, due to the anticipated increases in the amount of generated biosolids combined with issues surrounding potential environmental release and the limited availability of land for additional lagoons, other biosolids management strategies are being explored.

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Globally, slaughterhouses generate large volumes of animal byproducts. While these byproducts are an important resource of industrial protein that could potentially be utilized in various value-added applications, they are currently either underutilized in high-value applications or being used for production of relatively low-value products such as animal feed and pet food. Furthermore, some of the byproducts of animal slaughtering cannot enter food and feed chains and thus their disposal possesses a serious environmental concern.

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Specified risk materials (SRM) constitute the proteinaceous waste of slaughterhouses and are currently being disposed off either by incineration or by land filling. Over the last few years, our efforts have focused on developing technology platforms for deployment of this renewable resource for various value-added industrial applications. This report describes a technology for utilization of SRM for the development of an environmentally friendly plywood adhesive with an improved water resistance property.

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Background: The cellulosic ethanol industry has developed efficient strategies for converting sugars obtained from various cellulosic feedstocks to bioethanol. However, any further major improvements in ethanol productivity will require development of novel and innovative fermentation strategies that enhance incumbent technologies in a cost-effective manner. The present study investigates the feasibility of applying self-cycling fermentation (SCF) to cellulosic ethanol production to elevate productivity.

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Whey permeate was used as a co-substrate to replace part of the wheat for ethanol production by Saccharomyces cerevisiae. The simultaneous saccharification and fermentation was achieved with β-galactosidase added at the onset of the fermentation to promote whey lactose hydrolysis. Aspergillus oryzae and Kluyveromyces lactis β-galactosidases were two enzymes selected and used in the co-fermentation of wheat and whey permeate for the comparison of their effectiveness on lactose hydrolysis.

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