The Experts below are selected from a list of 7518 Experts worldwide ranked by ideXlab platform
Qinhong Wang - One of the best experts on this subject based on the ideXlab platform.
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ionic liquids based hydrolysis of Chlorella Biomass for fermentable sugars
Bioresource Technology, 2012Co-Authors: Na Zhou, Yimin Zhang, Xiaowu Gong, Qinhong WangAbstract:Abstract An ionic liquids-based chemical hydrolysis strategy was developed to obtain high-yielding soluble sugars from Chlorella Biomass. Initial ionic liquids dissolution and subsequently HCl catalyzed hydrolysis could dissolve 75.34% of Chlorella Biomass and release 88.02% of total sugars from Chlorella Biomass. The amount of HCl loading was 7 wt.% relative to Chlorella Biomass weight, which was much lower (only 14.6%) than that in HCl/MgCl2-catalyzed system with similar sugars release ( Zhou et al., 2011 ). Ionic liquids in the hydrolysates were recycled and fermentable sugars were evaluated by converting to bioethanol after separated by ion-exclusion chromatography. This ionic liquids-based hydrolysis strategy showed the great potential to produce fermentable sugars from algal Biomass.
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hydrolysis of Chlorella Biomass for fermentable sugars in the presence of hcl and mgcl2
Bioresource Technology, 2011Co-Authors: Na Zhou, Yimin Zhang, Xiaowu Gong, Qinhong WangAbstract:When Chlorella Biomass was hydrolyzed in the presence of 2% HCl and 2.5% MgCl2, a sugar concentration of nearly 12%, and a sugar recovery of about 83% was obtained. Fermentation experiments demonstrated that glucose in the Chlorella Biomass hydrolysates was converted into ethanol by Saccharomyces cerevisiae with a yield of 0.47 g g(-1), which is 91% of the theoretical yield. This chemical hydrolysis approach is thus a novel route for the hydrolysis of Biomass to generate fermentable sugars. (c) 2011 Elsevier Ltd. All rights reserved.
Vilém Zachleder - One of the best experts on this subject based on the ideXlab platform.
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microalgae novel highly efficient starch producers
Biotechnology and Bioengineering, 2011Co-Authors: Irena Branyikova, Jiří Doucha, Vilém Zachleder, Barbora Marsalkova, Tomas Branyik, Kateřina Bisova, Milada VitovaAbstract:The freshwater alga Chlorella, a highly productive source of starch, might substitute for starch-rich terrestrial plants in bioethanol production. The cultivation conditions necessary for maximizing starch content in Chlorella Biomass, generated in outdoor scale-up solar photobioreactors, are described. The most important factor that can affect the rate of starch synthesis, and its accumulation, is mean illumination resulting from a combination of Biomass concentration and incident light intensity. While 8.5% DW of starch was attained at a mean light intensity of 215 µmol/(m2 s1), 40% of DW was synthesized at a mean light intensity 330 µmol/(m2 s1). Another important factor is the phase of the cell cycle. The content of starch was highest (45% of DW) prior to cell division, but during the course of division, its cellular level rapidly decreased to about 13% of DW in cells grown in light, or to about 4% in those kept in the dark during the division phase. To produce Biomass with high starch content, it is necessary to suppress cell division events, but not to disturb synthesis of starch in the chloroplast. The addition of cycloheximide (1 mg/L), a specific inhibitor of cytoplasmic protein synthesis, and the effect of element limitation (nitrogen, sulfur, phosphorus) were tested. The majority of the experiments were carried out in laboratory-scale photobioreactors, where culture treatments increased starch content to up to about 60% of DW in the case of cycloheximide inhibition or sulfur limitation. When the cells were limited by phosphorus or nitrogen supply, the cellular starch content increased to 55% or 38% of DW, respectively, however, after about 20 h, growth of the cultures stopped producing starch, and the content of starch again decreased. Sulfur limited and cycloheximide-treated cells maintained a high content of starch (60% of DW) for up to 2 days. Sulfur limitation, the most appropriate treatment for scaled-up culture of starch-enriched Biomass, was carried out in an outdoor pilot-scale experiment. After 120 h of growth in complete mineral medium, during which time the starch content reached around 18% of DW, sulfur limitation increased the starch content to 50% of DW. Biotechnol. Bioeng. 2011; 108:766–776. © 2010 Wiley Periodicals, Inc.
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Production of Chlorella Biomass enriched by selenium and its use in animal nutrition: a review
Applied Microbiology and Biotechnology, 2009Co-Authors: Jiří Doucha, Karel Lívanský, Václav Kotrbáček, Vilém ZachlederAbstract:Feedstuffs are routinely supplemented with various selenium sources, where organic forms of Se are more bio-available and less toxic than the inorganic forms (selenites, selenates). When the algae are exposed to environmental Se in the form of selenite, they are able as other microorganisms to incorporate the element to different levels, depending on the algae species. Technology of heterotrophic fed-batch cultivation of the microalga Chlorella enriched by organically bound Se was developed, where the cultivation proceeds in fermentors on aerated and mixed nutrient solution with urea as a nitrogen and glucose as a carbon and energy source. High volumetric productivity and high cell concentrations (about 70–100 g Chlorella dry mass l^−1) can be attained if nutrients and oxygen are adequately supplied. Addition of a small quantity of a new selenoprotein source-spray-dried Se- Chlorella Biomass to the diet of farm animals had better effects on specific physiological and physical parameters of animals than selenite salt and was comparable with Se yeast added to the diet. This review introduces the importance of selenium for humans and animals, methods of Se determination, heterotrophic production of selenium-enriched Chlorella Biomass in a fed-batch culture regime on organic carbon, and use of the Biomass in animal nutrition.
Na Zhou - One of the best experts on this subject based on the ideXlab platform.
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ionic liquids based hydrolysis of Chlorella Biomass for fermentable sugars
Bioresource Technology, 2012Co-Authors: Na Zhou, Yimin Zhang, Xiaowu Gong, Qinhong WangAbstract:Abstract An ionic liquids-based chemical hydrolysis strategy was developed to obtain high-yielding soluble sugars from Chlorella Biomass. Initial ionic liquids dissolution and subsequently HCl catalyzed hydrolysis could dissolve 75.34% of Chlorella Biomass and release 88.02% of total sugars from Chlorella Biomass. The amount of HCl loading was 7 wt.% relative to Chlorella Biomass weight, which was much lower (only 14.6%) than that in HCl/MgCl2-catalyzed system with similar sugars release ( Zhou et al., 2011 ). Ionic liquids in the hydrolysates were recycled and fermentable sugars were evaluated by converting to bioethanol after separated by ion-exclusion chromatography. This ionic liquids-based hydrolysis strategy showed the great potential to produce fermentable sugars from algal Biomass.
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hydrolysis of Chlorella Biomass for fermentable sugars in the presence of hcl and mgcl2
Bioresource Technology, 2011Co-Authors: Na Zhou, Yimin Zhang, Xiaowu Gong, Qinhong WangAbstract:When Chlorella Biomass was hydrolyzed in the presence of 2% HCl and 2.5% MgCl2, a sugar concentration of nearly 12%, and a sugar recovery of about 83% was obtained. Fermentation experiments demonstrated that glucose in the Chlorella Biomass hydrolysates was converted into ethanol by Saccharomyces cerevisiae with a yield of 0.47 g g(-1), which is 91% of the theoretical yield. This chemical hydrolysis approach is thus a novel route for the hydrolysis of Biomass to generate fermentable sugars. (c) 2011 Elsevier Ltd. All rights reserved.
Pavel Hrouzek - One of the best experts on this subject based on the ideXlab platform.
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In vitro bioaccessibility of selenoamino acids from selenium (Se)-enriched Chlorella vulgaris Biomass in comparison to selenized yeast; a Se-enriched food supplement; and Se-rich foods.
Food chemistry, 2018Co-Authors: Kumar Saurav, Mykola Mylenko, Karolína Ranglová, Jan Kuta, Daniela Ewe, Jiří Masojídek, Pavel HrouzekAbstract:Abstract Selenium (Se) is an indispensable microelement in our diet and health issues resulting from deficiencies are well documented. Se-containing food supplements are available on the market including Se-enriched Chlorella vulgaris (Se-Chlorella) which accumulates Se in the form of Se-amino acids (Se-AAs). Despite its popular uses, data about the bioaccessibility of Se-AAs from Se-Chlorella are completely missing. In the present study, gastrointestinal digestion times were optimized and the in vitro bioaccessibility of Se-AAs in Se-Chlorella, Se-yeast, a commercially available Se-enriched food supplement (Se-supplement) and Se rich foods (Se-foods) were compared. Higher bioaccessibility was found in Se-Chlorella (∼49%) as compared to Se-yeast (∼21%), Se-supplement (∼32%) and Se-foods. The methods used in production of Se-Chlorella Biomass were also investigated. We found that disintegration increased bioaccessibility whereas the drying process had no effect. Similarly, temperature treatment by microwave oven also increased bioaccessibility whereas boiling water did not.
Jiří Doucha - One of the best experts on this subject based on the ideXlab platform.
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microalgae novel highly efficient starch producers
Biotechnology and Bioengineering, 2011Co-Authors: Irena Branyikova, Jiří Doucha, Vilém Zachleder, Barbora Marsalkova, Tomas Branyik, Kateřina Bisova, Milada VitovaAbstract:The freshwater alga Chlorella, a highly productive source of starch, might substitute for starch-rich terrestrial plants in bioethanol production. The cultivation conditions necessary for maximizing starch content in Chlorella Biomass, generated in outdoor scale-up solar photobioreactors, are described. The most important factor that can affect the rate of starch synthesis, and its accumulation, is mean illumination resulting from a combination of Biomass concentration and incident light intensity. While 8.5% DW of starch was attained at a mean light intensity of 215 µmol/(m2 s1), 40% of DW was synthesized at a mean light intensity 330 µmol/(m2 s1). Another important factor is the phase of the cell cycle. The content of starch was highest (45% of DW) prior to cell division, but during the course of division, its cellular level rapidly decreased to about 13% of DW in cells grown in light, or to about 4% in those kept in the dark during the division phase. To produce Biomass with high starch content, it is necessary to suppress cell division events, but not to disturb synthesis of starch in the chloroplast. The addition of cycloheximide (1 mg/L), a specific inhibitor of cytoplasmic protein synthesis, and the effect of element limitation (nitrogen, sulfur, phosphorus) were tested. The majority of the experiments were carried out in laboratory-scale photobioreactors, where culture treatments increased starch content to up to about 60% of DW in the case of cycloheximide inhibition or sulfur limitation. When the cells were limited by phosphorus or nitrogen supply, the cellular starch content increased to 55% or 38% of DW, respectively, however, after about 20 h, growth of the cultures stopped producing starch, and the content of starch again decreased. Sulfur limited and cycloheximide-treated cells maintained a high content of starch (60% of DW) for up to 2 days. Sulfur limitation, the most appropriate treatment for scaled-up culture of starch-enriched Biomass, was carried out in an outdoor pilot-scale experiment. After 120 h of growth in complete mineral medium, during which time the starch content reached around 18% of DW, sulfur limitation increased the starch content to 50% of DW. Biotechnol. Bioeng. 2011; 108:766–776. © 2010 Wiley Periodicals, Inc.
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Production of Chlorella Biomass enriched by selenium and its use in animal nutrition: a review
Applied Microbiology and Biotechnology, 2009Co-Authors: Jiří Doucha, Karel Lívanský, Václav Kotrbáček, Vilém ZachlederAbstract:Feedstuffs are routinely supplemented with various selenium sources, where organic forms of Se are more bio-available and less toxic than the inorganic forms (selenites, selenates). When the algae are exposed to environmental Se in the form of selenite, they are able as other microorganisms to incorporate the element to different levels, depending on the algae species. Technology of heterotrophic fed-batch cultivation of the microalga Chlorella enriched by organically bound Se was developed, where the cultivation proceeds in fermentors on aerated and mixed nutrient solution with urea as a nitrogen and glucose as a carbon and energy source. High volumetric productivity and high cell concentrations (about 70–100 g Chlorella dry mass l^−1) can be attained if nutrients and oxygen are adequately supplied. Addition of a small quantity of a new selenoprotein source-spray-dried Se- Chlorella Biomass to the diet of farm animals had better effects on specific physiological and physical parameters of animals than selenite salt and was comparable with Se yeast added to the diet. This review introduces the importance of selenium for humans and animals, methods of Se determination, heterotrophic production of selenium-enriched Chlorella Biomass in a fed-batch culture regime on organic carbon, and use of the Biomass in animal nutrition.