Biogas production through co-digestion of enzymatically pretreated corn bran and cow manure

Biogas production from wastes is an alternative that contributes positively to the environment and minimize the dependence on fossil energy sources. Additionally, the reuse of biomasses helps to reduce the waste production, but a pretreatment is required to use it in the anaerobic digestion. Here biogas was produced through co-digestion of enzymatically pretreated corn bran and cow manure. Firstly, it was selected the most hydrolysable waste (barley bagasse, sugar cane bagasse, elephant grass, thick orange pie, average orange pie, wheat bran, coffee grounds, orange peel, white sludge, vinasse, corn bran, soy bran, soy peel, cotton bran, cassava husk, cassava flour, banana peel, corn bran, sorghum stem, sorghum seed, total sorghum and wet distiller grain) by the crude extracts containing amylase (secreted by Aspergillus brasiliensis), xylanase (Aspergillus tamarii Kita) and cellulase (Trichoderma reesei, Novozymes®). Later on, different mixtures of these enzymes were studied using simplex-centroid designs. The most hydrolyzed waste by each enzyme individually (measured by reducing sugar using dinitrosalicylic acid, DNS) at 50°C, 120 rpm and 24 h were corn bran, banana peel and sorghum seed. Then, the simplex-centroid designs resulted in model equations and respective response surface contours. Amylase extract had a significant positive influence on corn bran hydrolysis by maximizing the reducing sugar yield when it was used individually (35g/L of reducing sugar). After it, the pretreated corn bran and a cow manure (1:2 g of volatile solids) were employed for biogas production in batch assays. It was found a biogas accumulation of 326 mL in the 12nd day of anaerobic codigestion, which were similar to the control (containing 35 g/L of glucose alone) and 53% higher than that found with corn bran without enzymatic pretreatment. In conclusion, it was observed that the crude extract optimized for amylase production affected significantly the corn bran hydrolyses and consequently the biogas production in a co-digestion with cow manure.CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico process 142139/2017-3)FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo process 2018/07522-6)FCT (Fundação para a Ciência e Tecnologia)info:eu-repo/semantics/publishedVersio

Enzymatically and/or thermally treated Macroalgae biomass as feedstock for fermentative H2 production

Due to its high carbohydrate content, algae biomass can be employed as feedstock to produce hydrogen (H2)by fermentation. However, to make the carbohydrates entrapped within the cell wall more bioavailable, algaebiomass must be treated before fermentation. We submitted Kappaphyccus alvarezzi macroalgae biomass toautoclave (at 120 °C and 1 atm for 6 h) treatment and/or enzymatic (Celluclast® and/or a recombinant β-glucosidase) hydrolysis, to break down complex carbohydrates into available sugars that were used to produceH2 by fermentation. Macroalgae biomass treated with Celluclast®+β-glucosidase and with combinedthermal treatment and enzymatic hydrolysis reached very similar TRS productivities, 0.24 and 0.22 g ofTRS/L.h, respectively. The enzymatically treated biomass was employed as feedstock to produce H2 byClostridium beijerinckii Br21, which afforded high yield: 21.3 mmol of H2/g of dry algae biomass. Hence,treatment with Celluclast® and recombinant β-glucosidase provided macroalgae biomass for enhanced bioconversionto H2 by C. beijerinckii Br21.Keywords: Kappaphyccus alvarezzi, Clostridium beijerinckii, Biohydrogen, Cellulase, β-glucosidas

Avaliação do ensaio de toxicidade com a alga Scenedesmus subspicatus para o estudo de efluentes industriais

Orientador: Nelson Eduardo Duran CaballeroTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuimicaDoutorad

Estudo das enzimas produzidas por Trichoderma longibrachiatum responsaveis pela degradação de materiais celulosicos

Orientador: Lucia Regina DurrantDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Um total de 626 microrganismos foram isolados de amostras de solos e de material celulósico em decomposição, coletadas em várias regiões brasileiras. Destes, um fungo mesofílico, o qual foi identificado como Trichoderma longibrachiatum, foi selecionado e utilizado em estudos de produção e caracterização de enzimas que promovem a degradação de materiais celulósicos. Celuloses comerciais e resíduas agroindustriais compuseram as fontes de carbono. As maiores atividades de hidrólise de papel de filtro, celulose microcristalina e carboximetilcelulose, foram obtidas, após crescimento do microrganismo em Solka-Floc, enquanto que ß-glicosidase e xilanase apresentaram um máximo de atividade após crescimento em meio líquido contendo bagaço de cana. A atividade do sistema celulolítico determinada por hidrólise de papel de filtro apresentou pH ótimo na faixa de 4.6 e 5.0 e conservou 87%. de sua atividade depois de 24 horas de incubação na faixa de pH 4.4 e 5.0. A temperatura ótima de ação o foi 65 C e após 1 hora e 24 horas de incubação a esta temperatura a enzima conservou em torno de 70% e 16% de sua atividade, respectivamente. O sistema enzimático produzido pelo fungo foi parcialmente purificado, após cromatografia em coluna DEAE Sephadex A-50 e filtração em gel Sephadex G-l00. O peso molecular de alguns de seus componentes foi estimado aproximadamente , obtendo-se uma ß-glicosidase de 44 kDa, duas xilanases de 14 e 16 kDa e uma exoglicanase de 60 kDa. Um mutante foi obtido por exposição da cepa isolada à luz ultravioleta. O mesmo apresentou características morfológicas diferentes da linhagem original e produção enzimática menor indicando possíveis alterações no sistema secretórioAbstract: A total of 626 microorganisms were isolated from samples of soil and biodegraded cellulosic material collected from various areas in Brazil. One mesophilic fungus which was identified as Trichoderma longibrachiatum was selected. The production and characterization of the enzymes, which promote the degradation of cellulosic materials, were studied. Relatively pure celluloses and agrindustrial residues were used as carbon sources. The highest filter paper rnicrocrystalline cellulose and carboxymetilcellulose hydrolysis activities were obtained following growth of the microorganism in Solka-Floc, whereas ß-g1ucosidase and xylanase exhibited the greatest activities after growth in sugar cane bagasse. The activity of the cellulolytic system determined as filter paper hydrolysis showed pH optimum at the 4.6-5.0 intervals and mantained 87% of its original activity after 24 hours incubation at the pH range 4.4-5.0. The optimum temperature for activity was 55 º C and after 1 hour and 24 hours incubation at this temperature de enzyme kept 70% and 15% respectively of its activity. The enzymatic system produced by the fungus was partially purified after DEAE-Sephadex A-50 column chromatography and Sephadex G-100 gel filtration. the molecular weight of some of the components was aproximately estimated getting a 44 kDa ß-glicosidase 14 and 16 kDa xylanases and a 60 kDa exoglucanase A mutant was obtained after exposition of the isolated strain to U. V. light. Its morphological characteristics were different from the original strain and its enzymatic production was lower indicating a possible alteration in the secretory systemMestradoMestre em Ciência de Alimento