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Development of integrated strategies using non-recombinant yeast for 2G ethanol production from lignocellulosic materials
(Universidade Federal de São Carlos, 2023-01-31) Sandri, Juliana Passamani; Milessi Esteves, Thais Suzane; https://lattes.cnpq.br/7000002745065879; Zangirolami, Teresa Cristina; https://lattes.cnpq.br/4546701843297248; https://lattes.cnpq.br/1321022414321714
The viability of second-generation (2G) ethanol production still requires overcoming some bottlenecks, such as the underutilization of the hemicellulosic fraction of biomass and process improvements to reach higher productivity and economic viability. In this sense, the present project aimed to study and develop strategies for efficient 2G ethanol production, taking full advantage of biomass sugars and using non-recombinant yeasts and commercial enzymes, besides evaluating processes integration for first (1G) and 2G ethanol production. Simultaneous Isomerization and Fermentation (SIF) studies were carried out with commercial yeasts (S. cerevisiae Itaiquara and FT858L) and enzymes (xylose isomerases IGI-HF and Sweetzyme IT extra). Both enzymes were adequate to operate under SIF conditions (pH 5.2, 35 °C), whilst the baker’s yeast Itaiquara had better performance in fermenting xylulose. Mass transfer limitations in the SIF were circumvented by designing and operating the denominated “enzyme-multiple-packed bed reactor” (EMPBR), consisting of several tubes for enzyme load (53 IU/mL), which enabled its recycling in a process that resulted in ethanol productivities of about 0.87 getOH/L/h in xylose synthetic medium. The EMPBR was also applied for Simultaneous (Saccharification) Isomerization and Co-Fermentation (SICF/SSICF). The best strategy for hexoses and pentoses co-fermentation was evaluated in a defined medium mimicking industrial hydrolysate, with 12% of the total ethanol produced coming from xylose. Then, EMPBR performance was evaluated in industrial media, consisting of hemicellulosic hydrolysates mixed with pretreated solids (2G) or molasses (1G), supplemented with the commercial enzyme preparation Cellic®CTec2, under the concepts of 1G/2G process integration and whole sugarcane bagasse use. Hydrothermal hydrolysate fermented in a sequential strategy with molasses resulted in 76% of xylose conversion and 46 g/L of ethanol titer. Co-cultures with the yeasts K. marxianus and S. cerevisiae, aiming at improvements in the co-fermentation of hexoses and pentoses, were carried out in 24 deep-well plates, which allowed the screening of different culture conditions. A promising xylose conversion (83%) was achieved compared to monoculture (52%, K. marxianus), in hemicellulosic hydrolysate medium supplemented with nutrients (35 °C, 150 rpm, Vmedium: 2/5 of deep-well volume, CXi: 5 g/L). Further studies of the enzymatic hydrolysis process of the entire fraction of pretreated sugarcane bagasse were conducted on a small scale, reaching 37.5% cellulose conversion with 20% (w/v) of solids after 72 h at 35 °C. Scaleup of the process was carried out in a bioreactor designed for high solid load (HSL) processes. Solid feeding strategies were evaluated, achieving 64 and 75% cellulose conversion with 22.5% solids (w/v) after 72 h at 35 and 50 °C, respectively. Simultaneous Saccharification and Co-Fermentation (SSCF) with 15% solids were conducted with co-culture under the optimal conditions found in the 24-well plate study, resulting in 98% glucose and 52% xylose conversions, respectively, in 72 h, ethanol yield of 0.23 getOH/gS and productivity of 0.28 getOH/L/h. However, cell viability loss was observed during the HSL bioreactor operation, requiring modifications in the culture strategy. Overall, a great advance in the 2G processes using non-recombinant yeasts and commercial enzymes was achieved, as well as promising results for integrating the 1G/2G ethanol production processes.
Isolamento e caracterização de bactérias rizosféricas de cagaiteira (Eugenia dysenterica) e seus efeitos na promoção de crescimento nas culturas da soja e do algodão
(Universidade Federal de São Carlos, 2023-01-31) Nadalini, Marilia Thomé; Cunha, Anderson Ferreira da; https://lattes.cnpq.br/0329741640375661; Dalio, Ronaldo José Durigan; https://lattes.cnpq.br/5725118850483397; https://lattes.cnpq.br/7846765146506337
Brazil occupies a prominent position in the global agricultural scenario, being the world's largest producer of soy, the main crop of Brazilian agribusiness, and the world's fourth largest producer of cotton. However, the presence of acidic and low fertility soils, combined with the quest to increase productivity, make Brazil the largest consumer of fertilizers, which increases production costs and generates environmental impacts. In this context, the use of microorganisms that promote plant growth is an important ally in agriculture, helping to mobilize and transport nutrients to the plant and also to tolerate biotic and abiotic factors. This work aims to verify the existence of bacteria that promote plant growth among isolates from the rhizosphere of cagaiteira (Eugenia dysenterica), a specie native of the savannah, found in regions with acidic soils and poor in nutrients, already used for bioprospecting microorganisms of biotechnological interest. The isolates that showed fast growth were submitted to an in vitro test to verify their ability to fix atmospheric nitrogen (N2), solubilize phosphate and potassium, and produce siderophores and biofilm. Based on in vitro analyses, bacteria 02, 04 and 06 were selected for tests in a greenhouse on soy and cotton crops. The biometric parameters height, aerial fresh mass, aerial dry mass, root dry mass, number and mass of pods for soy plants were evaluated at the end of the in vivo experiment. Isolate 02 promoted an increase of 35.63% in the root dry mass of cotton plants, while those inoculated with isolate 06 obtained an increase of 32.73%. Soy plants inoculated with bacteria 02 and 04 showed an increase of 13.33% and 11.67%, respectively, in the number of pods. The other evaluated parameters did not show statistically significant difference between treatments. From the results obtained, it can be seen that the interaction between plant and microorganisms varies according to the plant species and, furthermore, that the positive effects observed may be correlated to the ability of these microorganisms to fix N2, to solubilize phosphate and potassium and to produce biofilm and siderophores.
Ritmo climático, a partir de aspectos da precipitação pluviométrica, na região metropolitana de Sorocaba, entre os anos de 2000 a 2015
(Universidade Federal de São Carlos, 2023-01-31) Sá, Ivan Vasconcelos de Almeida; Silva, Edelci Nunes da; https://lattes.cnpq.br/7229161630393268; https://lattes.cnpq.br/2771113750760706
Study of the climate has evolved considerably throughout the years. In the climatic characterization of a locality, study the rhythm is important to know the dynamics on a certain scale, but also the interactions resulting from the movements that occur in the atmosphere.. The metropolitan region of Sorocaba was established in 2014, representing an intention of integration of some municipalities near Sorocaba. Later, in 2016, the municipality of Itapetininga was incorporated to this region The characterization of atmospheric phenomena can be realized by the Standard Years technique, wherever, from a given variable, the years are classified according to the similarities between these characteristics of atmospheric attributes, forming groups of years in common. With this characterization, it is possible to perform a rhythmic analysis of some periods within the selected interval. This work has as objective to establish the patterns and the spatio-temporal characteristics of rainfall in the Metropolitan Region of Sorocaba from the perspective of rhythmic analysis, between the years 2000 to 2015. For this purpose, we selected data from twenty pluviometers of DAEE present in the region, establishing the standard years. With this information, data from five weather stations were selected, being three from INMET and two from CIIAgro from January and July of 2009, 2013 and 2014. The use of Standard Deviation in relation to the mean to define the standard years in this area of study showed that there is a great diversity of characteristics to be watched in the Metropolitan Region of Sorocaba. Because of this, it is possible to observe that a certain year has characteristics of a rainy year in one location and another year in another location. In the rhythmic analyzes made in the Metropolitan Region of Sorocaba, it was possible to observe that each location presented different behaviors, even under the influence of the same atmospheric systems. Can contribute to it, factors such as altitude, vegetation, land use and the geographical location of the measurement site itself. These differentiations reinforce the transition aspect present in the RMS and show that it is important to know these characteristics in depth to properly understand the regional dynamics present.
Propriedades mecânicas e eletroquímicas do aço inoxidável AISI 410 goivado com eletrodo de grafita e soldado por arco submerso
(Universidade Federal de São Carlos, 2023-01-31) Figueiredo, Elvio; Bolfarini, Claudemiro; https://lattes.cnpq.br/9231627080617037; https://orcid.org/0000-0002-3099-3694; Koga, Guilherme Yuuki; https://lattes.cnpq.br/0933095081175012; https://orcid.org/0000-0003-0792-1139; https://lattes.cnpq.br/4617615399227314; https://orcid.org/0009-0006-2186-0132
In petrochemical industries, the electric arc gouging process with a graphite electrode is widely used for removing defective welds in carbon steel. It is a fast and simple process compared to grinding, and more economical than plasma gouging. However, for stainless steels, there is limited information in the literature regarding the amount of carbon deposited in stainless steel during gouging, and the risks of intergranular corrosion and loss of mechanical properties. No studies were found addressing the effect of gouging followed by submerged arc welding on ferritic stainless steels. Therefore, the present work aims to evaluate the metallurgical changes and their consequences on the mechanical and electrochemical properties resulting from gouging followed by submerged arc welding with AWS-ER 410 electrode, in AISI 410 stainless steel. The plates, before and after re-welding, were subjected to tensile and impact tests (Charpy). The degree of sensitization of the welded joint was evaluated through the double loop potentiokinetic reactivation technique (DL-EPR) according to ISO 12732, and the susceptibility to intergranular corrosion was tested according to ASTM A763, practice W. The study showed that gouging, even with appropriat parameters, can lead to sensitization. The intergranular corrosion susceptibility test showed the presence of pits in all samples. The potentiokinetic reactivation test showed a high degree of sensitization, above 5%, in samples subjected to gouging and those welded by submerged arc. Submerged arc welding on AISI 410 reduced toughness and increased the degree of sensitization. Therefore, the use of AISI 410 stainless steel subjected to gouging with a graphite electrode and welded by submerged arc is not recommended for use in the petrochemical industry.