Doctor of Philosophy / Department of Biological & Agricultural Engineering / Donghai Wang / Lignocellulosic biomass such as agricultural residues tends to be a sustainable feedstock for production of biofuels and biobased products in the long term due to its high availability and relative low cost. However, conversion of lignocellulosic biomass to biofuels faces significant technical challenges. One of the major challenges is biomass logistics. The agricultural residues are often harvested during a limited harvest season and stored as bales with low bulk density, making them difficult to handle, transport, store, and use in their natural forms. Densification of biomass by pelleting process could significantly improve the bulk density of biomass and thus improve handling efficiency and reduce transportation and handing costs. The main focus of this research was to better understand the impacts of pelleting process as well as pelleting conditions on physical properties, chemical compositions, biomass structure, and fermentable sugar yield of sorghum stalk, corn stover, wheat straw, and big bluestem. Results showed that pelleting process can increase biomass density up to 9-12 folds. Pelleting condition such as hammer mill screen size and ring-die pelleting mill die thickness had significant effects on bulk density, true density, and durability of biomass pellets. Although the pelleting process did not show significant effects on chemical composition of biomass before dilute-acid pretreatment process, glucan content of biomass pellets increased with the increase in ring-die pelleting mill die thickness and decreased with the increase in mill screen size after dilute-acid pretreatment. Opposite trend was observed for xylan content of biomass pellets as affected by pelleting conditions after dilute-acid pretreatment process. Biomass crystallinity increased after pelleting process, but not in a significant level. Softened surface region of biomass was removed after pelleting process, making the biomass more amendable to enzymatic attack. In this study, the optimum pelleting conditions were to grind the biomass feed using a 6.5-mm mill screen and to pellet biomass using a 44.5-mm ring-die pelleting mill die thickness. Under this optimum pelleting condition, the enzymatic conversion of cellulose of wheat straw pellets was the highest (94.1%), followed by corn stover pellet (93.1%), sorghum stalk pellet (92.1%), and big bluestem pellet (91.1%).

Peperomia pellucida (L.) HBK (Piperaceae) (erva de jaboti) é uma herbácea amplamente encontrada nos trópicos e que possui diversas propriedades biológicas. Seus estudos fitoquímicos haviam demonstrado a presença da pellucidina A, uma rara dinorlignana ciclobutânica, que seria formada por acoplamento oxidativo de 2,4,5- triidroxi-estireno seguido de metilações. Nesse trabalho, foram caracterizados o ácido 2,4,5-trimetoxi-cinâmico, 2,4,5-trimetoxi-estireno, 2,4,5-trimetoxi-benzaldeído, dilapiol, 5,6,7-trimetoxi-flavona, sesamina, além da pellucidina A. Estudos de aspectos dinâmicos envolvidos na formação da pellucidina A incluíram a ontogenia e respostas à diferentes tratamentos como estresse hídrico, predação por herbívoros, ácido jasmônico e luz UV360. O tratamento com ácido jasmônico resultou num significativo incremento do dilapiol enquanto que, o tratamento sob luz UV360 resultou no aumento na produção da pellucidina A sugerindo um mecanismo de cicloadição [2+2] para sua biossíntese. A administração de diferentes precursores in vivo revelou que a L-[2-13C]- fenilalanina (0,75%), ácido [8-13C]-cinâmico (1,32%), ácido [8-13C]-ferúlico (0,51%), ácido 2,4,5-trimetoxi-[8-13C]-cinâmico (7,9%) e o 2,4,5-trimetoxi-estireno (13,3%) foram incorporados à pellucidina A. Ensaios de conversão enzimática indicaram a descarboxilação do ácido 2,4,5-trimetoxi-cinâmico em 2,4,5-trimetoxi-estireno enquanto que o 2,4,5-trimetoxi-estireno foi dimerizado em pellucidina A através da reação de cicloadição [2+2] sensibilizada pela presença da 5,6,7-trimetoxi-flavona (18,45%), tal qual a benzofenona (11,15%). Assim, sugere-se a sequência L-fenilalanina, ácido cinâmico, ácido 2,4,5-trimetoxi-cinâmico, 2,4,5-trimetoxi-estireno e pellucidina A, sendo a última etapa através de mecanismo fotoquímico tendo como sensibilizador a 5,6,7-trimetoxi-flavona. / Peperomia pellucida (L.) HBK (Piperaceae) (erva de jaboti) is an herbaceous plant that is widespread in the tropics and have several biological properties. Previous reports described the presence of pellucidin A, a rare dinorlignan having the unique cyclobutane moiety, that was supposedly formed by oxidative coupling of the precursor 2,4,5-trihydroxy-styrene followed by methylations steps. In this study, a comprehensive phytochemical study resulted in the description of 2,4,5-trimethoxy-cinnamic acid, 5,6,7-trimethoxy-flavone, 2,4,5-trimethoxy-styrene, 2,4,5-trimethoxy-benzaldehyde, dillapiol and sesamin in addition to pellucidin A. Studies of the dynamic aspects involved in the formation of pellucidin A included changes during ontogeny and responses to different treatments such as drought stress, herbivory, jasmonic acid and UV360 light. The treatment with jasmonic acid resulted in a significant increase in dillapiol whereas treatment under UV360 light resulted in an increase in production of pellucidin A, suggesting that a cycloaddition [2+2] mechanism is involved in its formation. The in vivo administration of different precursors to plants of P. pellucida revealed that L-[2-13C]-phenylalanine (0.75%), [8-13C]-cinnamic acid (1.32%), [8-13C]-ferulic acid (0.51%) 2,4,5-trimethoxy-[8-13C]-cinnamic acid (7.9%) and 2,4,5-trimethoxy-[8-13C]-styrene (13.3%) were incorporated into pellucidin A. The enzymatic conversion assays indicated decarboxylation of 2,4,5-trimethoxy-cinnamic acid into 2,4,5-trimethoxy-styrene while the 2,4,5-trimethoxy-styrene was dimerized in the pellucidin A by cycloaddition reaction [2+2] sensitized by 5,6,7-trimethoxy-flavone (18.45%), as well as by benzophenone (11.15%). Thus, we suggest the sequence L-phenylalanine, cinnamic acid, 2,4,5-trimethoxy-cinnamic acid, 2,4,5-trimethoxy-styrene and pellucidin A, the last step being carried out by a photochemical mechanism having 5,6,7- trimethoxy-flavone as a sensitizer.

Peperomia pellucida (L.) HBK (Piperaceae) (erva de jaboti) é uma herbácea amplamente encontrada nos trópicos e que possui diversas propriedades biológicas. Seus estudos fitoquímicos haviam demonstrado a presença da pellucidina A, uma rara dinorlignana ciclobutânica, que seria formada por acoplamento oxidativo de 2,4,5- triidroxi-estireno seguido de metilações. Nesse trabalho, foram caracterizados o ácido 2,4,5-trimetoxi-cinâmico, 2,4,5-trimetoxi-estireno, 2,4,5-trimetoxi-benzaldeído, dilapiol, 5,6,7-trimetoxi-flavona, sesamina, além da pellucidina A. Estudos de aspectos dinâmicos envolvidos na formação da pellucidina A incluíram a ontogenia e respostas à diferentes tratamentos como estresse hídrico, predação por herbívoros, ácido jasmônico e luz UV360. O tratamento com ácido jasmônico resultou num significativo incremento do dilapiol enquanto que, o tratamento sob luz UV360 resultou no aumento na produção da pellucidina A sugerindo um mecanismo de cicloadição [2+2] para sua biossíntese. A administração de diferentes precursores in vivo revelou que a L-[2-13C]- fenilalanina (0,75%), ácido [8-13C]-cinâmico (1,32%), ácido [8-13C]-ferúlico (0,51%), ácido 2,4,5-trimetoxi-[8-13C]-cinâmico (7,9%) e o 2,4,5-trimetoxi-estireno (13,3%) foram incorporados à pellucidina A. Ensaios de conversão enzimática indicaram a descarboxilação do ácido 2,4,5-trimetoxi-cinâmico em 2,4,5-trimetoxi-estireno enquanto que o 2,4,5-trimetoxi-estireno foi dimerizado em pellucidina A através da reação de cicloadição [2+2] sensibilizada pela presença da 5,6,7-trimetoxi-flavona (18,45%), tal qual a benzofenona (11,15%). Assim, sugere-se a sequência L-fenilalanina, ácido cinâmico, ácido 2,4,5-trimetoxi-cinâmico, 2,4,5-trimetoxi-estireno e pellucidina A, sendo a última etapa através de mecanismo fotoquímico tendo como sensibilizador a 5,6,7-trimetoxi-flavona. / Peperomia pellucida (L.) HBK (Piperaceae) (erva de jaboti) is an herbaceous plant that is widespread in the tropics and have several biological properties. Previous reports described the presence of pellucidin A, a rare dinorlignan having the unique cyclobutane moiety, that was supposedly formed by oxidative coupling of the precursor 2,4,5-trihydroxy-styrene followed by methylations steps. In this study, a comprehensive phytochemical study resulted in the description of 2,4,5-trimethoxy-cinnamic acid, 5,6,7-trimethoxy-flavone, 2,4,5-trimethoxy-styrene, 2,4,5-trimethoxy-benzaldehyde, dillapiol and sesamin in addition to pellucidin A. Studies of the dynamic aspects involved in the formation of pellucidin A included changes during ontogeny and responses to different treatments such as drought stress, herbivory, jasmonic acid and UV360 light. The treatment with jasmonic acid resulted in a significant increase in dillapiol whereas treatment under UV360 light resulted in an increase in production of pellucidin A, suggesting that a cycloaddition [2+2] mechanism is involved in its formation. The in vivo administration of different precursors to plants of P. pellucida revealed that L-[2-13C]-phenylalanine (0.75%), [8-13C]-cinnamic acid (1.32%), [8-13C]-ferulic acid (0.51%) 2,4,5-trimethoxy-[8-13C]-cinnamic acid (7.9%) and 2,4,5-trimethoxy-[8-13C]-styrene (13.3%) were incorporated into pellucidin A. The enzymatic conversion assays indicated decarboxylation of 2,4,5-trimethoxy-cinnamic acid into 2,4,5-trimethoxy-styrene while the 2,4,5-trimethoxy-styrene was dimerized in the pellucidin A by cycloaddition reaction [2+2] sensitized by 5,6,7-trimethoxy-flavone (18.45%), as well as by benzophenone (11.15%). Thus, we suggest the sequence L-phenylalanine, cinnamic acid, 2,4,5-trimethoxy-cinnamic acid, 2,4,5-trimethoxy-styrene and pellucidin A, the last step being carried out by a photochemical mechanism having 5,6,7- trimethoxy-flavone as a sensitizer.

Made available in DSpace on 2016-06-02T19:55:43Z (GMT). No. of bitstreams: 1 6832.pdf: 3214384 bytes, checksum: 0ef6f81368240fad0ee476c019e48c11 (MD5) Previous issue date: 2015-03-27 / Universidade Federal de Sao Carlos / Sugarcane bagasse (SCB) is a by-product generated after sugarcane milling in the process of manufacture of sugar and/or ethanol. In this study, pretreated SCB was used in different configurations of enzymatic hydrolysis and fermentation. The objective was obtaining the greatest amounts of fermentable sugars in the enzymatic conversion and then converted them to ethanol. SCB was hydrothermally pretreated (1:10 (w/v), solid-liquid ratio) under the conditions 170 °C/15 min, 195°C/10 min, and 195 °C/60 min at 200 rpm. The delignification step of the hydrothermal pretreated SCB was carried out with 0.02 and 0.5% NaOH solution at 1:10 (w/v). Pretreated and untreated samples of SCB were chemical and morphologically characterized. Enzymatic hydrolysis and fermentation assays were carried out in PSSF (pre-saccharification prior to simultaneous saccharification and fermentation) process. In the best condition, (10% pretreated SCB at 195 °C/10 min) it was obtained 57.4% of ethanol yield. SSF (simultaneous saccharification and fermentation) experiments were performed in Erlenmeyer flasks at 250 rpm and at 37 °C using commercial Saccharomyces cerevisiae during 72 h. In the first assay, it was evaluated the effect of initial buffered medium and non-buffered medium for hydrothermal pretreated SCBs. In the best result, it was obtained 53.8% of enzymatic conversion and an ethanol titer of 17.1 g/L (SCB pretreated at 195 °C/10 min in buffered medium). In the next assays, it was evaluated the effect of solid loading (10 and 15%) on delignified and non-delignified SCB using an enzyme loading of 20 FPU/g pretreated SCB. In these assays were obtained ethanol yields of 53.8 (17.1 g/L) and 60.0% (28.4 g/L) for 10 and 15% of SCB, respectively. These results showed that the increased in solid loading favored obtaining higher ethanol yield. Assays in SHF configuration (separate hydrolysis and fermentation) using delignified and non-delignified samples of SCB achieve ethanol concentration of 39.9 g/L and ethanol yield was 84% with 15% loading at 72 h. Other experiments were carried out in 10% SCB/15 FPU/g SCB loading, 10% SCB/30 FPU/g SCB loading, 15% SCB/15 FPU/g SCB loading and 15% SCB/30 FPU/g SCB loading employing the thermotolerant yeasts Kluyveromyces marxianus IMB3 and Saccharomyces cerevisiae D5A to ethanol production from hydrothermal pretreated SCB. The results showed enzymatic conversion was 64.3% and maximum ethanol concentration of 29.2 g/L using 15% of SCB at 72 h. D5A yeast showed ethanol yield was 76.2% and the maximum ethanol concentration of 42.6 g/L at 120 h using 15% of solid load and 30 FPU/g SCB of enzyme load. Overall, all evaluated conditions showing satisfactory results in obtaining ethanol from hydrothermal pretreated SCB. However, high concentration of substrate loading favored SHF process to operate separately enzymatic hydrolysis and fermentation. This configuration achieved high ethanol yields in the conditions assessed in this work. / O bagaço de cana-de-açúcar (BCA) é um subproduto gerado após a moagem da cana-deaçúcar no processo de produção de açúcar e/ou etanol. No presente trabalho, o BCA pré-tratado foi utilizado em diferentes configurações de hidrólise enzimática e fermentação com o objetivo de obter a maior quantidade de açúcares fermentescíveis na sacarificação e convertê-los a etanol. O BCA foi pré-tratado hidrotermicamente na proporção 1:10 (m/v) nas condições 170 °C/15 min, 195 °C/10 min e 195 °C/60 min com agitação de 200 rpm. A etapa de deslignificação do BCA prétratado hidrotermicamente foi realizada com 0,02 e 0,5% de solução de NaOH na proporção 1:10 (m/v). Amostras de BCA pré-tratada e não tratada foram caracterizadas quimicamente e morfologicamente. Os primeiros ensaios de hidrólise enzimática e fermentação foram realizados na configuração PSSF (pré-sacarificação e fermentação simultâneas). Na melhor condição (10% de BCA tratado a 195 °C/10 min) foi obtido rendimento em etanol de 57,5%. Os experimentos de SSF (sacarificação e fermentação simultâneas) foram realizados em frascos de Erlenmeyers com agitação de 250 rpm a 37 °C com levedura Saccharomyces cerevisiae comercial por 72 h. Nos primeiros ensaios avaliou-se o efeito do meio inicial tamponado e não tamponado para os BCAs pré-tratados hidrotermicamente. No melhor resultado obteve-se 53,8% de conversão enzimática e concentração de etanol de 17,1 g/L (BCA tratado a 195 °C/10 min em meio tamponado. Nos ensaios seguintes, avaliou-se o efeito da carga de sólidos (10 e 15%) para amostras de BCA deslignificada e não deslignificada utilizando carga enzimática de 20 FPU/g BCA tratado. Nesses ensaios obteve-se máximos rendimentos em etanol de 53,8 e 60,0% e concentrações de etanol 17,1 e 28,4 g/L com 10 e 15% de BCA, respectivamente. Esses resultados mostraram que o aumento na carga de sólidos favoreceu o aumento no rendimento em etanol. Nos ensaios em configuração SHF (sacarificação e fermentação separadas) utilizando amostras de BCA deslignificada e não deslignificada obteve-se concentração de etanol de 39,9 g/L e rendimento em etanol de 84,0% com 15% de sólidos em 72 h. Ensaios nas configurações 10% BCA/15 FPU/g BCA tratado, 10% BCA/30 FPU/g BCA tratado, 15% BCA/15 FPU/g BCA tratado e 15% BCA/30 FPU/g BCA tratado foram realizados empregando as leveduras Kluyveromyces marxianus IMB3 e Saccharomyces cerevisiae D5A na produção de etanol a partir do BCA pré-tratado hidrotermicamente. Os resultados mostraram conversão enzimática de 64,3% e concentração máxima de etanol de 29,2 g/L utilizando 15% de sólidos em 72 h para IMB3. Para a levedura D5A obteve-se rendimento em etanol de 76,2% e a máxima concentração de etanol de 42,6 g/L em 120 h utilizando 15% de sólidos e 30 FPU/g BCA tratado. De modo geral, todas as condições avaliadas apresentaram resultados satisfatórios na obtenção de etanol a partir do BCA pré-tratado hidrotermicamente. Entretanto, cargas de substrato maiores favoreceram a configuração SHF por operar separadamente a hidrólise enzimática e a fermentação alcançando maiores rendimento em etanol nas condições avaliadas nesse trabalho.