scholarly journals Factors Affecting Detoxification of Softwood Enzymatic Hydrolysates Using Sodium Dithionite

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 887
Author(s):  
Dimitrios Ilanidis ◽  
Stefan Stagge ◽  
Björn Alriksson ◽  
Leif J. Jönsson

Conditioning of lignocellulosic hydrolysates with sulfur oxyanions, such as dithionite, is one of the most potent methods to improve the fermentability by counteracting effects of inhibitory by-products generated during hydrothermal pretreatment under acidic conditions. The effects of pH, treatment temperature, and dithionite dosage were explored in experiments with softwood hydrolysates, sodium dithionite, and Saccharomyces cerevisiae yeast. Treatments with dithionite at pH 5.5 or 8.5 gave similar results with regard to ethanol productivity and yield on initial glucose, and both were always at least ~20% higher than for treatment at pH 2.5. Experiments in the dithionite concentration range 5.0–12.5 mM and the temperature range 23–110 °C indicated that treatment at around 75 °C and using intermediate dithionite dosage was the best option (p ≤ 0.05). The investigation indicates that selection of the optimal temperature and dithionite dosage offers great benefits for the efficient fermentation of hydrolysates from lignin-rich biomass, such as softwood residues.

2018 ◽  
Vol 13 (1) ◽  
pp. 45-52
Author(s):  
Aynura Manaf kizi Ismayilova ◽  

2020 ◽  
Vol 27 (6) ◽  
pp. 551-556
Author(s):  
Nidhya N. Joghee ◽  
Gurunathan Jayaraman ◽  
Masilamani Selladurai

Background: Nε-acetyl L-α lysine is an unusual acetylated di-amino acid synthesized and accumulated by certain halophiles under osmotic stress. Osmolytes are generally known to protect proteins and other cellular components under various stress conditions. Objective: The structural and functional stability imparted by Nε-acetyl L-lysine on proteins were unknown and hence was studied and compared to other commonly known bacterial osmolytes - ectoine, proline, glycine betaine, trehalose and sucrose. Methods: Effects of osmolytes on the temperature and pH profiles, pH stability and thermodynamic stability of the model enzyme, α-amylase were analyzed. Results: At physiological pH, all the osmolytes under study increased the optimal temperature for enzyme activity and improved the thermodynamic stability of the enzyme. At acidic conditions (pH 3.0), Nε-acetyl L-α lysine and ectoine improved both the catalytic and thermodynamic stability of the enzyme; it was reflected in the increase in residual enzyme activity after incubation of the enzyme at pH 3.0 for 15 min by 60% and 63.5% and the midpoint temperature of unfolding transition by 11°C and 10°C respectively. Conclusion: Such significant protective effects on both activity and stability of α-amylase imparted by addition of Nε-acetyl L-α lysine and ectoine at acidic conditions make these osmolytes interesting candidates for biotechnological applications.


2012 ◽  
Vol 20 (7) ◽  
pp. 695-700 ◽  
Author(s):  
Toru Sugihara ◽  
Hideo Yasunaga ◽  
Hiromasa Horiguchi ◽  
Tetsuya Fujimura ◽  
Hiroaki Nishimatsu ◽  
...  

2011 ◽  
Vol 3 (3) ◽  
pp. 414-416 ◽  
Author(s):  
Nathan H Boyd ◽  
Raul M Cruz

Abstract Background The objective of this study was to determine the extent of interest in international electives among prospective otolaryngology residents and to determine whether the availability of international electives affected students' interest in ranking a particular residency program. Methods A 3-part survey was given to all medical students enrolled in the 2008 otolaryngology match via the Electronic Residency Application Service. Part 1 elicited demographic information. Part 2 explored general interest in international rotations. Part 3 involved ranking several factors affecting students' choice of residency programs. This survey was developed at our institution, with no formal validation. Participation was anonymous and voluntary. Results A total of 307 students entered the otolaryngology match, and 55 surveys (18%) were completed. Twenty-five of 55 students (55%) had completed an international elective during or prior to medical school, and 51 of 55 respondents (93%) had a “strong” or “very strong” desire to participate in an international elective during residency; 48 of 55 students (87%) had a “strong” or “very strong” desire to participate in international surgical missions after residency. Future practice goals had no correlation with interest in international rotations, either during or after residency training. Respondents ranked 8 factors that had an impact on residency program selection in the following order of importance: operative experience, location, lifestyle, research opportunities, didactics, international electives, prestige of program, and salary. Conclusion Interest in international medicine among prospective otolaryngologists was high in this subset of respondents but did not appear to affect residency program selection.


2005 ◽  
Vol 83 (9) ◽  
pp. 1240-1245 ◽  
Author(s):  
Iain J Stenhouse ◽  
H Grant Gilchrist ◽  
William A Montevecchi

The selection of breeding habitat is of prime importance for individual fitness. Among birds, natural selection should favour the ability to recognize and select habitat suitable for nesting and rearing chicks. This study compares the characteristics of Sabine's Gull, Xema sabini (Sabine, 1819), nest sites with random points across a coastal tundra environment on Southampton Island, Nunavut, Canada. The availability of terrestrial invertebrate prey was also examined among habitats. Sabine's Gull nests were nonrandomly distributed in relation to vegetation, substrate, and proximity to water. Gulls nested within approximately 1 km of the coastline and selected sites with the greatest proportions of moss and standing water (i.e., they nested close to the edge of small freshwater ponds near shore). However, there were no detectable differences in characteristics between successful and unsuccessful nests within preferred habitat. The dynamics of terrestrial invertebrate prey communities varied between years, but the volume of invertebrates in Sabine's Gull nesting habitat was intermediate between the most productive habitats and the least productive habitats in both years. However, nest-site selection in Sabine's Gulls may also be influenced by the availability of aquatic invertebrates (not examined in this study) and their proximity to the marine coastline, where chicks are taken to be reared.


2014 ◽  
Vol 5 (1) ◽  
pp. 97-124 ◽  
Author(s):  
Mehdi Behboudi ◽  
Hossein Vazifehdoust ◽  
Kobra Najafi ◽  
Mina Najafi

Purpose – The purpose of this study is to verify the factors affecting the use of emotional and rational appeals in online advertising among Muslim customers in Iran. Design/methodology/approach – By reviewing the literature of advertising appeals and developing a comprehensive theoretical model, the effect of rational and emotional appeals on online advertising was examined. Expert questionnaire was administered to verify the validity of collected features. The Student's t-test was utilized to analyze the data collected from 271 participants. Findings – Five latent variables, namely user type, product involvement, e-lifestyle, advertising strategies, and internet motives were examined to explain factors affecting online advertising appeals among Muslim customers in Iran. It was found that “advertising strategies” and “user type” are the most effective factors influencing Muslims customers in developing an online advertising campaign. Research limitations/implications – The sample of this study was Iranian experts and it is necessary to conduct a survey with a larger sample size. Originality/value – This study provides insights into factors affecting the selection of emotional and rational appeals in Muslims countries. Moreover, it reports the primary columns of online advertising appeals.


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