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Study on pretreatment and hydrolysis of selected lignocellulose materials
Kovářová, Markéta ; Dvořák, Miloš (referee) ; Obruča, Stanislav (advisor)
This diploma thesis is focused on study of chemical and enzymatical hydrolysis of raw wood material. The aim of this work was to find the suitable method for pretreatment of selected lignocellulose materials. The theoretical part deals with characterization of lignocellulosic material and its components. There are also subscribed various pretreatment methods and their effect on hydrolysis of sawdust. In experimental part of the work the most appropriate approach of pretreatment and hydrolysis of sawdust was studied. Criteria for the selection of suitable method was concentration of saccharides as desired product of hydrolysis and also concentration of the most important microbial inhibitors - polyphenols. Application of 96% ethanol or 5% H2O2 were identified as the most promising pretreatment methods which enhanced yields of fermentable sugars about 30 %. Further, we also performed cultivation of bacteria Burkholderia cepacia and bacteria Burkholderia sacchari using solution obtained by hydrolysis of lignocellulose material.
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Metabolism of Bacterial Cells and the Effect of Stress on Biosynthesis of PHA
Kučera, Dan ; Kráčmar, Stanislav (referee) ; Ondrejovič,, Miroslav (referee) ; Obruča, Stanislav (advisor)
This thesis deals with the study of polyhydroxyalkanoate biosynthesis as a microbial product with the potential to replace current conventional plastics made from petroleum. The dissertation thesis is elaborated in the form of a discussed set of already published publications, which are then part of the thesis in the form of appendices. The work builds on relatively extensive knowledge in the field of polyhydroxyalkanoate production and brings new facts and possible strategies. Various possibilities of analysis of polyhydroxyalkanoates using modern methods were tested in this work, which brings especially speed, which can be crucial in real-time evaluation of production biotechnological process. Raman spectroscopy has proven to be a very promising technique for rapid quantification of PHA. Furthermore, the work deals with valorisation of waste of food and agricultural origin. Emphasis is placed on methods of detoxification of lignocellulose hydrolysates. In this context, adsorption of inhibitors to lignin was first used as an alternative to other detoxification techniques. Due to detoxification, selected production strains Burkholederia cepacia and B. sacchari were able to utilize softwood hydrolyzate for PHA production. In the next part of the work was also tested the possibility of using chicken feathers as a complex source of nitrogen. Evolutionary engineering was also used as a possible strategy to eliminate the inhibitory effect of levulic acid as a microbial inhibitor that results from the hydrolysis of lignocellulosic materials. Adaptation experiments were used to develop strains exhibiting higher resistance to levulic acid and the ability to accumulate a higher 3HV copolymer from the original wild-type C. necator strain. Another promising approach tested in the work was the use of extremophilic microbial strain, which leads to a reduction in the cost of biotechnological production. Selected Halomonas species have shown high potential as halophilic PHA producers. The final part of the thesis was devoted to the selection of the production strain with regard to the properties of the resulting PHA. The Cupriavidus malaysiensis strain was selected to produce a P(3HB-co-3HV-co-4HB) terpolymer which revealed significant differences in material properties over P3HB.
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Lignocellulosic Nanomaterials: Preparation, Characterization and Applications
Mishra, Pawan Kumar
In this thesis, Brewers Spent Grains (BSG), which is commonly available by-product from brewing industry was used to prepare CNF and characterized for morphological, chemical and thermal characteristics and Kraft lignin was used to synthesize lignin-based solid and hollow colloids and characterized, an application in UV protection was studied. In application, applications in drug delivery and nanobiocomposites were studied. To study application in drug delivery review of metal and ceramic nanoparticles were made and the anticancer drug was loaded on CNF aerogel and tested for drug release studies (our contribution was to prepare Nanocellulose based scaffold and help in the morphological evaluation, rest of the work was done by a collaborating group). In nanocomposites, a book chapter was written enlisting biopolymers including nanocellulose with title smart nanocomposites in food packaging.
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Metabolism of Bacterial Cells and the Effect of Stress on Biosynthesis of PHA
Kučera, Dan ; Kráčmar, Stanislav (referee) ; Ondrejovič,, Miroslav (referee) ; Obruča, Stanislav (advisor)
This thesis deals with the study of polyhydroxyalkanoate biosynthesis as a microbial product with the potential to replace current conventional plastics made from petroleum. The dissertation thesis is elaborated in the form of a discussed set of already published publications, which are then part of the thesis in the form of appendices. The work builds on relatively extensive knowledge in the field of polyhydroxyalkanoate production and brings new facts and possible strategies. Various possibilities of analysis of polyhydroxyalkanoates using modern methods were tested in this work, which brings especially speed, which can be crucial in real-time evaluation of production biotechnological process. Raman spectroscopy has proven to be a very promising technique for rapid quantification of PHA. Furthermore, the work deals with valorisation of waste of food and agricultural origin. Emphasis is placed on methods of detoxification of lignocellulose hydrolysates. In this context, adsorption of inhibitors to lignin was first used as an alternative to other detoxification techniques. Due to detoxification, selected production strains Burkholederia cepacia and B. sacchari were able to utilize softwood hydrolyzate for PHA production. In the next part of the work was also tested the possibility of using chicken feathers as a complex source of nitrogen. Evolutionary engineering was also used as a possible strategy to eliminate the inhibitory effect of levulic acid as a microbial inhibitor that results from the hydrolysis of lignocellulosic materials. Adaptation experiments were used to develop strains exhibiting higher resistance to levulic acid and the ability to accumulate a higher 3HV copolymer from the original wild-type C. necator strain. Another promising approach tested in the work was the use of extremophilic microbial strain, which leads to a reduction in the cost of biotechnological production. Selected Halomonas species have shown high potential as halophilic PHA producers. The final part of the thesis was devoted to the selection of the production strain with regard to the properties of the resulting PHA. The Cupriavidus malaysiensis strain was selected to produce a P(3HB-co-3HV-co-4HB) terpolymer which revealed significant differences in material properties over P3HB.
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Study on pretreatment and hydrolysis of selected lignocellulose materials
Kovářová, Markéta ; Dvořák, Miloš (referee) ; Obruča, Stanislav (advisor)
This diploma thesis is focused on study of chemical and enzymatical hydrolysis of raw wood material. The aim of this work was to find the suitable method for pretreatment of selected lignocellulose materials. The theoretical part deals with characterization of lignocellulosic material and its components. There are also subscribed various pretreatment methods and their effect on hydrolysis of sawdust. In experimental part of the work the most appropriate approach of pretreatment and hydrolysis of sawdust was studied. Criteria for the selection of suitable method was concentration of saccharides as desired product of hydrolysis and also concentration of the most important microbial inhibitors - polyphenols. Application of 96% ethanol or 5% H2O2 were identified as the most promising pretreatment methods which enhanced yields of fermentable sugars about 30 %. Further, we also performed cultivation of bacteria Burkholderia cepacia and bacteria Burkholderia sacchari using solution obtained by hydrolysis of lignocellulose material.
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