In this study, the aim was enzymatic xylooligosaccharide production from cotton and sunflower stalks, two of main agricultural residues in Turkey. In first two parts of the study, alkali extracted xylan from both of the stalks was hydrolyzed by commercial xylanases Veron and Shearzyme. The effect of temperature, pH, enzyme and substrate concentrations were investigated to determine optimum enzymatic hydrolysis conditions of xylan. Sunflower and cotton stalk xylans were hydrolyzed by Shearzyme more efficiently than Veron under the conditions studied. Shearzyme produced different product profiles containing xylobiose (X2), xylotriose (X3), xylotetrose (X4) and xylopentose (X5) from cotton and sunflower stalk xylan. On the other hand, Veron hydrolyzed both xylan types to produce X2, X3, X5, X6 and larger xylooligosaccharides without any change in product profiles. In the third part of the study, home produced xylanase from Bacillus pumilus SB-M13, was also investigated for the production of xylooligosaccharides from both cotton and sunflower stalk xylan. The main products obtained by hydrolysis of both substrates by pure B. pumilus xylanase were X5 and X6, while crude B. pumilus xylanase generated X4 and X5 as the main products. Xylooligosaccharide production from pretreated cotton stalk without alkali extraction of xylan was the final part of the study. Three different pretreatment methods including biomass pretreatment by Phanerochaete chrysosporium fermentation, cellulase pretreatment and hydrothermal pretreatment were investigated to break down complex lignocellulosic structure of cotton stalk to improve the subsequent enzymatic hydrolysis of xylan in pretreated cotton stalk for xylooligosaccharide production. However, xylooligosaccharide was not effectively produced from pretreated cotton stalk. Shearzyme inhibiton was observed after all the pretreatment methods during further hydrolysis of pretreated cotton stalk probably due to production of inhibitory compounds of the enzyme.

In the first part of the study, birchwood xylan-lignin film formation was studied. After film forming effect of lignin on pure birchwood xylan was demonstrated, the minimum lignin concentration necessary to form films was determined as 1.1% (lignin/xylan). So, it was determined that keeping about one percent lignin in xylan (w/w) was sufficient for film formation. Biodegradability of the lignin-birchwood xylan composite films was investigated enzymatically using 0.21 U / ml xylanase in an accelerated test. All the films containing lignin were hydrolyzed by xylanase showing biodegradability of the films. Colors of the birchwood xylan-lignin composite films containing different lignin concentrations were compared. Deviations of the color from the reference color were similar between the films. In the second part of the study, photocatalytic antimicrobial film production was investigated on wheat gluten-based films. In order to produce antimicrobial films, wheat gluten films were coated with a semiconductor, titanium dioxide (TiO2), applying different procedures. Coated films were illuminated and photocatalytical inactivation of Escherichia coli on films were determined by antimicrobial tests. The coating procedure in which titanium dioxide (TiO2) was produced from titanium tetraisopropoxide (TTIP) in aqueous-nitric acid and aqueous-hydrochloric acid solutions gave the best antimicrobial result but the films turned out to be deformed and brittle. Spreading TiO2 sol-gel on semi-dried wheat gluten films resulted in flexible and undeformed films having about 40% antimicrobial activity.

Mainly used food packaging materials are petro-chemical based polymers which present environmental problems since they are not biodegradable and ecologically sustainable. In this study, biodegradable biofilms are produced from xylan, extracted from cotton stalk which is an agricultural biowaste without nutritional value. Antimicrobial property was given to the biofilms with either titanium dioxide sol-gel coatings or titanium dioxide powder addition into the biofilm forming solutions. The antimicrobial activities of biofilms were tested against Escherichia coli. Among two different sol-gels coated and at different temperatures dried biofilms, BWX and CSX-50 biofilms treated at 120&deg / C and coated with SiO2/TiO2 showed 88&plusmn / 1% and 75&plusmn / 2% antimicrobial activities, respectively. Same samples treated at the same conditions but coated with non-SiO2 added TiO2 sol-gel yielded 63&plusmn / 3% and 63&plusmn / 2% antimicrobial activities, respectively after 2 h black light illumination. So, it was determined that the highest photocatalytic antimicrobial property was achieved with SiO2/TiO2 coated biofilms. Moreover different concentrations of TiO2 powder were integrated into xylan based biofilms and 100% photocatalytic inactivation was gathered at 5% (w/w) TiO2 addition achieved at both biofilms at the end of 90 min black light illumination. Biodegradability properties of the biofilms were investigated in soil burial test during 180 days and 10% (w/w) TiO2 powder added CSX-50 biofilms were recorded to be 91% biodegradable where non-powder added blank biofilms was found to be 95% biodegradable.

Xylan was extracted from cotton waste, characterized by DSC and TGA analysis and used in biodegradable film production. Pure cotton waste xylan did not form film. The presence of an unknown compound, as an impurity, yielded composite films. The unknown compound was determined as a phenolic compound, and most probably lignin, by using DSC and TGA analysis and Folin-Ciocalteau method. The effects of xylan concentration of the film forming solutions, glycerol (plasticizer) and gluten additions on thickness, mechanical properties, solubility, water vapor transfer rate, color and microstructure of the films were investigated. Films were formed within the concentration range of 8-14%. Below 8%, film forming solutions did not produce films, whereas xylan concentrations above 14% was not used because of high viscosity problems. The average tensile strength, strain at break, water vapor transfer rate and water solubility of the cotton waste xylan films were determined as about 1.3 MPa, 10%, 250 g/m2.24h and 99%, respectively. The addition of glycerol as the plasticizer resulted in a decrease in the tensile strength and an increase in strain at break. The change in water solubility due to the addition of glycerol was very small. In addition, water vapor transfer rate and the deviation of the color from the reference color for the plasticized films were found to be higher than the unplasticized films. The effect of addition of wheat gluten in cotton waste xylan film forming solutions on film formation was investigated at different concentration ratios. However, the incorporation of wheat gluten worsen the film quality.

Submitted by (lucia.rodrigues@ufrpe.br) on 2016-05-23T13:07:09Z No. of bitstreams: 1 Anna Carolina da Silva.pdf: 1738062 bytes, checksum: 8a7486e43be42611cf895a1cc7556737 (MD5) / Made available in DSpace on 2016-05-23T13:07:09Z (GMT). No. of bitstreams: 1 Anna Carolina da Silva.pdf: 1738062 bytes, checksum: 8a7486e43be42611cf895a1cc7556737 (MD5) Previous issue date: 2013-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The xylanases randomly hydrolyzes β-1,4-glycosidic bonds of xylan, producing xylooligomers of different sizes, therefore, these enzymes can be used in the diet of monogastric animals to hydrolyze the non-starch polysaccharides like β-glucans and arabinoxylans found in cereals, improving feed conversion and weight gain by decreasing the anti-nutritional effects caused by xylan. All sources of xylanase, filamentous fungi are interesting from the industrial viewpoint, because they have a high enzyme production when compared to other micro-organisms in fermentation processes. The production cost of the enzyme is concentrated mainly in the post-fermentation processes in an attempt to obtain pure enzyme. The application of extractive fermentation decreases cost by the reduction in purification steps of the molecule. The objective of this work by producing xylanase in ATPS extractive fermentation by Aspergillus tamarii URM 4634, scale production in bioreactors, the enzyme partially characterize and evaluate the influence of their activity in monogastric digestion. The xylanase had a better performance at acidic pH (3.6) and 90 ° C, proving to be stable to pH and temperature, maintaining its activity above 40 and 50% respectively, for 180 minute test. Most ions and inhibitors tested did not significantly alter its activity. The xylanase has great potential to be applied in the feed industry for its features and especially for having behaved positively in simulated gastric digestion. / As xilanases hidrolisam aleatoriamente ligações β-1,4-glicosídicas da xilana, produzindo xilooligomêros de diferentes tamanhos; por esta razão, essas enzimas podem ser utilizadas na dieta de animais monogástricos para hidrolisar os polissacarídeos não-amiláceos como β-glucanos e arabinoxilanos encontrados em cereais, melhorando a conversão alimentar e o ganho de peso, por diminuírem o efeito anti-nutricional causado pela xilana. De todas as fontes de xilanases, os fungos filamentosos são interessantes do ponto de vista industrial, pelo fato de terem alta produção de enzimas quando comparados a outros micro-organismos em processos fermentativos. O custo de produção da enzima concentra-se, principalmente, nos processos pós-fermentativos na tentativa de se obter a enzima pura. A fermentação extrativa diminui o custo pela redução nas etapas de purificação da molécula. Objetivou-se com este trabalho produzir xilanase por fermentação extrativa em sistemas de duas fases aquosas (SDFA) por Aspergillus tamarii URM 4634, escalonar a produção em biorreatores, caracterizar parcialmente a enzima e avaliar a influência da sua atividade na digestão monogástrica. A xilanase produzida teve melhor desempenho em pH ácido (3,6) e a 90 °C, demonstrando ser estável ao pH e à temperatura, mantendo sua atividade acima dos 40 e 50%, respectivamente, nos 180 minutos de ensaio. A maioria dos íons e substâncias inibidoras testadas não alterou significativamente sua atividade. A xilanase tem grande potencial para ser aplicada na indústria de rações por suas características e principalmente por ter comportado positivamente na simulação da digestão gástrica.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21837号 / 農博第2350号 / 新制||農||1069(附属図書館) / 学位論文||H31||N5209(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 田中 千尋, 教授 本田 与一, 准教授 刑部 正博 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

The kraft process is a complex system with many variables, and though the process is fairly well understood, there is still much we do not know.      This thesis examines some aspects of the kraft process that could prove to be of interest for the pulp and paper industry, specifically, the impact of wood chip impregnation and of the chemical structure of xylan on spruce kraft pulp. The intent is to suggest modifications to the kraft process as it is used today.      The effect of wood chip impregnation varies with the prevalent conditions, and increases the effect of the subsequent kraft cook. Longer impregnation at a lower temperature was found to increase screened pulp yield, reduce shives content, make it possible to reach a certain kappa number at a lower H-factor, and make it possible to reach a certain kappa number at a lower total alkali consumption.      Xylan has previously been found to have a strength-enhancing effect on pulp, and the chemical structure of the xylan in question was found to be the main strength-enhancing factor. For spruce xylan, the structure that provides the largest increase in strength is not the same as the structure that increases the yield the most. Removing xylan was determined to have a negative impact on pulp strength.      Xylan extracted from agro waste can be used as an additive to increase pulp strength. This could be viable, especially when combined with the production of green plastics from hemicelluloses extracted from the agro waste.      A suggested configuration of a future pulp mill is presented, incorporating the following modifications to the now standard kraft cooking system: impregnation at a lower temperature for a longer time; extracting xylan-enriched black liquor at an early stage of the impregnation or cook, and adding this liquor at a late stage of the cook; terminating the cook at a higher kappa number; increasing oxygen delignification to compensate for the increased kappa number at the end of the cook, keeping the kappa number constant going into the bleaching plant; and adding agro-waste xylan during oxygen delignification. / <p>QC 20150525</p>

Efterfrågan på förnyelsebara och miljövänliga produkter har ökat under de senaste åren. Biobaserade plaster anses vara en av de mest lovande innovationer.    Det övergripande målet med examensarbetet var att undersöka möjligheterna att utvinna xylan och glukomannan ur rapshalm. Metoden som utnyttjades var en hydrotermisk extraktion. Inverkan av temperatur, pH och tid studerades genom att tillämpa ett faktorförsök på två nivåer. En askhalt- och torrhalt-analys utfördes på produkterna för att dels bestämma andelen oorganiskt material, dels beräkna det totala utbytet. Hemicellulosans molekylvikt bestämdes med hjälp av en SEC-analys. Kolhydratsammansättningen och andelen lignin i varje prov avslöjdes genom att utföra en kolhydratanalys. Två väletablerade tekniker (NMR (Nuclear magnetic resonance) och FTIR (Fourier transform infrared spectroscopy)) användes i detta arbete för bestämning av strukturen. NMR utnyttjades för att studera förhållandet mellan sockret och sidogrupperna medan IR användes för identifiering av de funktionella grupperna som förekommer i varje prov. Hemicellulosan som togs fram i projektet användes till gjutning av plastfilmer vars mekaniska egenskaper studerades genom att utföra dragprovningar.   Resultaten påvisade ett högt utbyte av produkt i samband med höga koncentrationer av NaOH. Andelen oorganiskt material var högre för de prover som behandlades med enbart vatten jämfört med de prover som behandlades med alkali. IC-analysen påvisade att glukomannan utsöndras med vatten medan utbytet av xylan blir högre vid behandling med alkali. IC-analysen visade även att den specifika typen av xylan i den undersökta rapshalmen utgörs av arabinoglukuronoxylan. SEC-analysen fastställde att vattenbehandlade prover har en högre molekylvikt. Ett oväntat resultat var att mängden lignin som erhölls i de vattenbehandlade proverna var högre än de som erhölls vid alkalibehandling. Resultaten från NMR- och IR- analyserna påvisade förekomsten av polysackarider i de olika proven. Dragprovningen visade att jämnt fördelade andelar xylan och glukomannan tillsammans med en hög molekylvikt bidrog till en större förmåga hos materialet att kunna bemöta den ökade belastningen.

The effect of xylan from different plant species on tensile properties of spruce pulp was studied. Xylans from spruce, birch, wheat straw and rice husks were mixed with the fresh white liquor and added at the later stages of separate kraft cooks, in exchange of the black liquor removed from the system at that time. Results show that xylans, from rice husk, wheat straw and birch, gave stronger pulps. However it was only possible to attach small quantities of xylans onto the fibers. Moreover, pulps containing birch and rice xylan were easier to beat than the other pulps in the study.

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