Analysis of the galactomannan binding ability of β-mannosidases, BtMan2A and CmMan5A, regarding their activity and synergism with a β-mannanase

Both β-mannanases and β-mannosidases are required for mannan-backbone degradation into mannose. In this study, two β-mannosidases of glycoside hydrolase (GH) families 2 (BtMan2A) and 5 (CmMan5A) were evaluated for their substrate specificities and galactomannan binding ability. BtMan2A preferred short manno-oligomers, while CmMan5A preferred longer ones; DP >2, and galactomannans. BtMan2A displayed irreversible galactomannan binding, which was pH-dependent, with higher binding observed at low pH, while CmMan5A had limited binding. Docking and molecular dynamics (MD) simulations showed that BtMan2A galactomannan binding was stronger under acidic conditions (-8.4 kcal/mol) than in a neutral environment (-7.6 kcal/mol), and the galactomannan ligand was more unstable under neutral conditions than acidic conditions. Qualitative surface plasmon resonance (SPR) experimentally confirmed the reduced binding capacity of BtMan2A at pH 7. Finally, synergistic β-mannanase to β-mannosidase (BtMan2A or CmMan5A) ratios required for maximal galactomannan hydrolysis were determined. All CcManA to CmMan5A combinations were synergistic (≈1.2-fold), while combinations of CcManA with BtMan2A (≈1.0-fold) yielded no hydrolysis improvement. In conclusion, the low specific activity of BtMan2A towards long and galactose-containing oligomers and its non-catalytic galactomannan binding ability led to no synergy with the mannanase, making GH2 mannosidases ineffective for use in cocktails for mannan degradation.The National Research Foundation (NRF) of South Africa, Rhodes University and the University of Pretoria.http://www.elsevier.com/locate/csbjhj2023BiochemistryGeneticsMicrobiology and Plant Patholog

Spitzer Warm Mission Archive Science Opportunities

The rich data archive from the Spitzer cryogenic mission will be comprised of approximately 25 TB of data. A five-year warm mission would add an additional 15–20 TB. All of these data will be processed and archived to form homogeneous, reliable database to support research for decades after the end of the Spitzer mission. The SSC proposes a robust archival research program during the warm mission phase. A sampling of possible archival programs are described

Beyond adoption: A new framework for theorising and evaluating Non-adoption, Abandonment and challenges to Scale-up, Spread and Sustainability (NASSS) of health and care technologies

© 2017 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in the Journal of Medical Internet Research, is properly cited. The complete bibliographic information, a link to the original publication on http://www.jmir.org/, as well as this copyright and license information must be included.Background: Many promising technological innovations in health and social care are characterized by nonadoption or abandonment by individuals or by failed attempts to scale up locally, spread distantly, or sustain the innovation long term at the organization or system level. Objective: Our objective was to produce an evidence-based, theory-informed, and pragmatic framework to help predict and evaluate the success of a technology-supported health or social care program. Methods: The study had 2 parallel components: (1) secondary research (hermeneutic systematic review) to identify key domains, and (2) empirical case studies of technology implementation to explore, test, and refine these domains. We studied 6 technology-supported programs—video outpatient consultations, global positioning system tracking for cognitive impairment, pendant alarm services, remote biomarker monitoring for heart failure, care organizing software, and integrated case management via data sharing—using longitudinal ethnography and action research for up to 3 years across more than 20 organizations. Data were collected at micro level (individual technology users), meso level (organizational processes and systems), and macro level (national policy and wider context). Analysis and synthesis was aided by sociotechnically informed theories of individual, organizational, and system change. The draft framework was shared with colleagues who were introducing or evaluating other technology-supported health or care programs and refined in response to feedback. Results: The literature review identified 28 previous technology implementation frameworks, of which 14 had taken a dynamic systems approach (including 2 integrative reviews of previous work). Our empirical dataset consisted of over 400 hours of ethnographic observation, 165 semistructured interviews, and 200 documents. The final nonadoption, abandonment, scale-up, spread, and sustainability (NASSS) framework included questions in 7 domains: the condition or illness, the technology, the value proposition, the adopter system (comprising professional staff, patient, and lay caregivers), the organization(s), the wider (institutional and societal) context, and the interaction and mutual adaptation between all these domains over time. Our empirical case studies raised a variety of challenges across all 7 domains, each classified as simple (straightforward, predictable, few components), complicated (multiple interacting components or issues), or complex (dynamic, unpredictable, not easily disaggregated into constituent components). Programs characterized by complicatedness proved difficult but not impossible to implement. Those characterized by complexity in multiple NASSS domains rarely, if ever, became mainstreamed. The framework showed promise when applied (both prospectively and retrospectively) to other programs.Peer reviewe

THE EFFECT OF ALCOHOLS, LIGNIN AND PHENOLIC COMPOUNDS ON THE ENZYME ACTIVITY OF CLOSTRIDIUM CELLULOVORANS XynA

In the production of biofuel from lignocellulose biomass, particularly in the case of consolidated bioprocessing where the saccharification and fermentation steps take place within the same bioreactor, many compounds may be present that could affect the enzymes within such a bioreactor. This study examined the effect of ethanol, butanol, propanol, lignin, -coumaric acid, and gallic acid on the activity of XynA from C. cellulovorans. XynA from C. cellulovorans was purified, and the effects of various compounds on enzyme activity were assayed using the dinitrosalicylic acid method. In this study, it was found that XynA was very tolerant to ethanol and only lost 25% of activity even at high concentrations of ethanol. In the presence of lignin, XynA was inhibited at very low levels and retained ~85% of its activity. The highest degree of inhibition of XynA was experienced in the presence of -coumaric acid (38%) and gallic acid (47%). The results indicate that the most problematic compounds within the bioreactor are likely to be soluble lignin degradation products resulting from pretreatment steps. Therefore, the removal of these compounds prior to saccharification should result in increased productivity within a bioreactor. This study indicates that XynA may be a suitable hemicellulase for use in bioethanol production, as it has very high tolerance for ethanol inhibition

The inhibitory effects of various substrate pre-treatment by-products and wash liquors on mannanolytic enzymes

publisher versionBiomass pre-treatment is essential for achieving high levels of bioconversion through increased accessibility of hydrolytic enzymes to hydrolysable carbohydrates. However, pre-treatment by-products, such as sugar and lignin degradation products, can negatively affect the performance of hydrolytic (mannanolytic) enzymes. In this study, two monomeric sugars, five sugar degradation products, five lignin derivatives and four liquors from biomass feedstocks pre-treated by different technologies, were evaluated for their inhibitory effects on mannanolytic enzymes (α-galactosidases, β-mannanases and β-mannosidases). Lignin derivatives elicited the greatest inhibitory effect on the mannanolytic enzymes, followed by organic acids and furan derivatives derived from sugar degradation. Lignin derivative inhibition appeared to be as a result of protein–phenolic complexation, leading to protein precipitating out of solution. The functional groups on the phenolic lignin derivatives appeared to be directly related to the ability of the phenolic to interfere with enzyme activity, with the phenolic containing the highest hydroxyl group content exhibiting the greatest inhibition. It was also demonstrated that various pre-treatment technologies render different pre-treatment soluble by-products which interact in various ways with the mannanolytic enzymes. The different types of biomass (i.e. different plant species) were also shown to release different by-products that interacted with the mannanolytic enzymes in a diverse manner even when the biomass was pre-treated using the same technology. Enzyme inhibition by pre-treatment by-products can be alleviated through the removal of these compounds prior to enzymatic hydrolysis to maximize enzyme activity

Potential yields and emission reductions of biojet fuels produced via hydrotreatment of biocrudes produced through direct thermochemical liquefaction

Background: The hydrotreatment of oleochemical/lipid feedstocks is currently the only technology that provides significant volumes (millions of litres per year) of “conventional” biojet/sustainable aviation fuels (SAF). However, if biojet fuels are to be produced in sustainably sourced volumes (billions of litres per year) at a price comparable with fossil jet fuel, biomass-derived “advanced” biojet fuels will be needed. Three direct thermochemical liquefaction technologies, fast pyrolysis, catalytic fast pyrolysis and hydrothermal liquefaction were assessed for their potential to produce “biocrudes” which were subsequently upgraded to drop-in biofuels by either dedicated hydrotreatment or co-processed hydrotreatment. Results: A significant biojet fraction (between 20.8 and 36.6% of total upgraded fuel volume) was produced by all of the processes. When the fractions were assessed against general ASTM D7566 specifications they showed significant compliance, despite a lack of optimization in any of the process steps. When the life cycle analysis GHGenius model was used to assess the carbon intensity of the various products, significant emission reductions (up to 74%) could be achieved. Conclusions: It was apparent that the production of biojet fuels based on direct thermochemical liquefaction of biocrudes, followed by hydrotreating, has considerable potential.Forestry, Faculty ofNon UBCReviewedFacult

Fruit waste streams in South Africa and their potential role in developing a bio-economy

Current and previous studies on bio-based (fruit) wastes and wastewaters, with a particular emphasis on research in South Africa, were reviewed. Previous studies have focused predominantly on the beneficiation and application of fruit waste as a feedstock for renewable energy. A definite gap in knowledge and application of fruit waste streams with regard to enzyme production as a value-added product is identified. The characteristics and composition of each type of fruit waste are highlighted and their potential as feedstocks in the production of value-added products is identified. The conversion of agri-industrial wastewaters to bioenergy and value-added products is discussed, with special mention of the newly published South African Bio-Economy Strategy, and the potential production of biofuels and enzymes from waste streams using recombinant Aspergillus strains. Finally, to maximise utilisation of waste streams in South Africa and abroad, a conceptual model for an integrated system using different technologies is proposed

Fruit waste streams in South Africa and their potential role in developing a bio-economy

CITATION: Khan, N. et al. 2015. Fruit waste streams in South Africa and their potential role in developing a bio-economy. South African Journal of Science, 111(5/6), Art. #2014-0189, doi:10.17159/sajs.2015/20140189.The original publication is available at http://sajs.co.zaCurrent and previous studies on bio-based (fruit) wastes and wastewaters, with a particular emphasis on research in South Africa, were reviewed. Previous studies have focused predominantly on the beneficiation and application of fruit waste as a feedstock for renewable energy. A definite gap in knowledge and application of fruit waste streams with regard to enzyme production as a value-added product is identified. The characteristics and composition of each type of fruit waste are highlighted and their potential as feedstocks in the production of value-added products is identified. The conversion of agri-industrial wastewaters to bioenergy and value-added products is discussed, with special mention of the newly published South African Bio-Economy Strategy, and the potential production of biofuels and enzymes from waste streams using recombinant Aspergillus strains. Finally, to maximise utilisation of waste streams in South Africa and abroad, a conceptual model for an integrated system using different technologies is proposed.http://sajs.co.za/fruit-waste-streams-south-africa-and-their-potential-role-developing-bio-economy/nuraan-khan-marilize-le-roes-hill-pamela-j-welz-kerry-grandin-tukayi-kudanga-j-susan-van-dyk-colinPublisher's versio

Diffusion-Weighted PFGNMR Study of Molecular Level Interactions of Loops and Direct Bridges of HEURs on Latex Particles

Viscosity building in latex coatings to provide desirable shear thinning rheological properties is a key property commercially achieved with hydrophobically modified ethylene oxide urethane (HEUR) rheology modifiers (RMs). Prior studies focused on the aqueous solution properties of HEURs, resulting in the well-known transient network model that describes solution rheology reasonably well. Relatively fewer studies have probed the molecular level interactions between the hydrophobe groups of HEUR and latex surfaces under conditions of realistic latex volume fractions and HEUR concentration. The presence of ubiquitous surfactant and oligomer molecules in the latex aqueous phase makes it difficult to detect these interactions directly for any off-the-shelf (industrial) materials. In this work, we outline the use of pulsed field gradient (PFG) NMR spectroscopy as diffusion-weighted filter to remove the signals of low molecular weight species in order to detect hydrophobe end groups and urethane linkers. This in situ approach does not have any perturbation issues that are inherent in prior methods involving centrifugation and avoids the questions raised by the use of custom pyrene hydrophobes in fluorescence spectroscopy. From this study we conclude that there are no HEUR transient network structures present in HEUR–latex composites with less than about 2% HEUR and 30% latex relevant for coatings applications. Our results explain the shear thinning rheology of latex–HEUR composites based on molecular level interactions between hydrophobe end groups and urethane linkers of HEURs and latex particles to produce HEUR PEO loops on latex and direct bridges between pairs of latex particles