http://hdl.handle.net/11422/28233 Sun, 26 Jul 2026 06:49:47 GMT 2026-07-26T06:49:47Z http://hdl.handle.net/11422/29591 Title: Potencial de produção de biogás a partir de resíduos de madeira Author(s)/Inventor(s): Soares, Nathália Bulcão Advisor: Prast, Alex Enrich Abstract: Anaerobic digestion (AD) is a promising technology for waste treatment, converting organic matter into bioproducts such as biogas and digestate, which offer socio-environmental and economic benefits. In riverside communities in the Amazon, where access to centralized energy systems is limited, this technology can offer an efficient and sustainable solution for energy generation. Sawdust, a byproduct of sustainable forest management, represents a promising raw material for biogas production, with an estimated generation of between 6.3 and 10.5 Mton/year⁻¹ in the region. However, its complex lignocellulosic structure hinders the degradation of organic matter, limiting methane (CH4) production. To overcome these limitations, pretreatment strategies with acetic acid (CH3COOH) and sulfuric acid (H2SO4) at concentrations of 6% and 8% were evaluated, aiming to optimize CH4 production in biochemical methane potential (BMP) assays from sawdust of six Amazonian tree species: Calycophyllum spruceanum, Ocotea cymbarum Kunth, Piranhea trifoliata, Calophyllum brasiliense Camb, Platymiscium ulei Harms, and Guarea trichilioides L. The BMP assays indicated that pretreatment with 8% CH3COOH was the most efficient, increasing CH4 yield by up to 17% for Calophyllum brasiliense Camb and 65% for Calycophyllum spruceanum, compared to untreated sawdust. For Guarea trichilioides L., the CH4 yield increased by 18% and 20% with 6% H2SO4 and 8% CH3COOH, respectively. However, for Ocotea cymbarum Kunth and Platymiscium ulei Harms, the untreated sawdust showed a higher CH₄ yield than the pretreated samples, possibly due to the presence of recalcitrant compounds released or formed during the acid pretreatment, reducing the biodegradability of the material. In terms of electrical energy generation, the untreated sawdust of Ocotea cymbarum Kunth obtained the highest potential (~1612 kWh/year), while Calycophyllum spruceanum pretreated with 8% CH₃COOH reached 2.668 kWh/year. Furthermore, Piranhea trifoliata digestate had the highest total nitrogen (TN) content (27.22 mg/g), while Platymiscium ulei Harms showed the highest total organic carbon (TOC) content (397.37 mg/g) and a C/N ratio of 20.6, making it suitable for nutrient-poor soils. These results indicate that AD of sawdust can reduce dependence on fossil fuels and synthetic fertilizers, while fully meeting household energy needs and providing an approximate 31% energy surplus, underscoring its potential as a resilient solution for decentralized energy systems in remote areas. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Tue, 27 May 2025 00:00:00 GMT http://hdl.handle.net/11422/29591 2025-05-27T00:00:00Z http://hdl.handle.net/11422/29588 Title: Efeitos de bioinoculantes com bactérias que promovem o crescimento de plantas (BPCP) em três variedades de tomate (Lycopersicum esculentum, MILL) Author(s)/Inventor(s): Saint-Preux, Esther Advisor: Hemerly, Adriana Silva Abstract: Tomato is one of the main vegetables cultivated in Brazil, with significant economic and social importance, contributing a substantial part of the national agricultural (45,1%) PIB. To increase production and ensure the global food demand, modern agricultural practices rely on chemical fertilizers, which have negative consequences for human health and the environment. However, agriculture faces a crucial challenge: to develop precision tools to enhance crop growth and productivity without these negative impacts. The use of bioinoculants based on PGPB is an important biotechnological alternative to reduce the excessive use of chemical nitrogen fertilizers. Thus, associations between beneficial bacteria and non-leguminous plants, such as tomatoes, can provide essential information for improving tomato cultivation in Brazil and worldwide. The main objective of this work is to investigate the effects of three bioinoculants composed of PGPB in three tomato varieties, aiming to identify the best associations to optimize growth, seeking the development of sustainable and easy-to-manage technologies. Inoculation experiments were conducted in a greenhouse, where plants were inoculated at 7 days after sowing (DAS) with Azospirillum baldaniorum Sp245, Herbaspirillum seropedicae HRC54, and the commercial bioinoculant Biofree, in addition to a control group (mock). Samples were collected at 14 DAS (7 DAI) and 37 DAS (30 DAI) for phenotypic analyses, performed during the vegetative growth of tomato plants. The results of inoculation experiments with the three tomato varieties (Cereja, Rasteiro Rio Grande and Microtom) in a greenhouse indicate that the efficacy of bioinoculants varies according to the combination between the variety and the bacteria used. The strain A. baldaniorum Sp245 stood out in the Cereja variety, promoting significant increases in plant height and biomass. In the Rasteiro Rio Grande variety, H. seropedicae HRC54 was more effective, especially at 30 days after inoculation, increasing the height and weight of the shoots and roots. For the Microtom variety, the three inoculation treatments were effective in increasing biomass, both of the shoots and roots, in tomato plants. Inoculation with SP245 and Biofree, in particular, showed promise, promoting a more robust development of this variety. To evaluate the best combination of tomato variety and bioinoculant under field conditions, the Cherry tomato variety was selected, as it showed good responsiveness to bioinoculants in the greenhouse. The selected bioinoculants were A. baldaniorum Sp245 and Biofree. The study was carried out in urban cultivation, through a partnership with the Hortas Cariocas Project. In this study, analyses were performed during the vegetative growth of the tomato plant. Fruiting was analyzed in another PhD thesis work. The results of the field experiment with the Cherry tomato variety, inoculation with A. baldaniorum Sp245 resulted in significant increases in plant height, fresh and dry weight of the shoot and roots. In addition, both Sp245 and the commercial bioinoculant Biofree significantly increased the levels of chlorophyll a, b, total and carotenoids in the plants, indicating improvements in the photosynthetic capacity. These findings highlight the promising potential of combining the Cereja variety with the bioinoculants Sp245 and Biofree to improve the development and physiological efficiency of tomato plants under field conditions. The findings reinforce the potential of bioinoculants in promoting tomato growth, highlighting the importance of selecting specific combinations between genotypes and bacteria to optimize agricultural productivity and sustainability. In addition, increased efficiency in the plant-bacteria association may contribute to reducing fertilizer and water consumption, promoting more sustainable agricultural practices. Publisher: Universidade Federal do Rio de Janeiro Type: Dissertação Mon, 02 Jun 2025 00:00:00 GMT http://hdl.handle.net/11422/29588 2025-06-02T00:00:00Z http://hdl.handle.net/11422/29131 Title: Elaboração de modelos preditivos da potencial atividade antiviral de espécies da biodiversidade brasileira frente ao SARS-CoV-2 através de métodos computacionais Author(s)/Inventor(s): Gomes, Brendo Araujo Advisor: Leitão, Suzana Guimarães Abstract: SARS-CoV-2 can cause multisystemic damage with a risk of death and has been responsible for high infection and mortality rates, often underreported. Plant secondary metabolites have shown promise as antiviral agents by strengthening the immune system, protecting against infections, and inhibiting viral replication—particularly through interaction with targets such as the Spike protein and viral proteases 3CLpro and PLpro. Brazil’s vast biodiversity offers great potential for the discovery of new bioactive molecules. Additionally, computational tools such as predictive models and molecular networks accelerate the screening and identification of compounds with activity against COVID-19, optimizing resources and expanding therapeutic possibilities. In this context, the present study aimed to develop predictive models capable of identifying potential plant species and their bioactive compounds by using chemical and biological screenings of extracts from the Fito-Extractoteca, with possible antiviral activity against SARS-CoV-2. The data from these screenings were used to construct predictive models through chemometric methods, as well as to generate molecular networks for qualitative investigation and annotation of the predicted substances. The chemical and biological screening steps yielded promising results in identifying plant species with anti-SARS-CoV-2 inhibitory potential. Moreover, data mining and molecular networking approaches proved to be essential contributors to the refinement of the developed models and to complementary analyses. The results highlight the potential of Brazilian biodiversity as a source of anti-SARS-CoV-2 agents, with multitarget activity through distinct mechanisms. The predictive models optimized the search for anti-SARS-CoV-2 substances and provided meaningful insights for the improvement of subsequent assays. Furthermore, these models—based on experimental screenings— facilitated the study of complex matrices and emerged as promising alternatives to less precise assays, such as molecular docking, or more costly strategies like bioassay-guided fractionation and dereplication. These advances represent significant progress in the search for new drug candidates against COVID-19, by leveraging Brazil’s plant diversity and applying computational methods to streamline the screening and identification of antiviral compounds. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Tue, 29 Apr 2025 00:00:00 GMT http://hdl.handle.net/11422/29131 2025-04-29T00:00:00Z http://hdl.handle.net/11422/28657 Title: Análise genômica e produção de biossurfactantes e/ou bioemulsificantes por três espécies novas dos gêneros Paenibacillus e Psychrobacillus Author(s)/Inventor(s): Argentino, Isabella Campelo Vilardi Advisor: Seldin, Lucy Abstract: The growing demand for alternatives to synthetic surfactants has driven increased interest in research on biosurfactants and bioemulsifiers due to their ecological and sustainable properties. However, despite their advantages, the production of these compounds, especially on a large scale, still faces challenges related to cost and yield. In this context, the search for new bacterial species capable of producing biosurfactants and bioemulsifiers, combined with the development of strategies to optimize their production, is essential. Furthermore, studying the metabolic pathways involved in the biosynthesis of these compounds allows for the identification of regulatory mechanisms, improvement of production efficiency, and exploration of potential biotechnological applications. Recently, the strains LABEM I01 and LABEM I02 (related to the Paenibacillus genus) and LABEM I03 (related to the Psychrobacillus genus) were isolated by our research group. Therefore, the objectives of this study were: (i) optimize cultivation conditions aiming to enhance the production of biosurfactants and bioemulsifiers; (ii) to genetically and functionally characterize the strains LABEM I01, LABEM I02 (Paenibacillus sp.), and LABEM I03 (Psychrobacillus sp.), determining their genomic diversity, metabolic pathways, and biotechnological potential. Emulsification and drop-collapse tests revealed that all the studied bacteria produce biosurfactants and/or bioemulsifiers. Subsequently, experimental design analyses were conducted to determine the optimal production conditions for biosurfactants and/or bioemulsifiers by LABEM I01, LABEM I02, and LABEM I03. The results indicated that the optimal production temperature for all strains was 34°C. Regarding surface tension, while the biosurfactant and/or bioemulsifier production by LABEM I02 was not influenced by medium salinity and pH, LABEM I01 exhibited higher production at pH 9 and 2% salinity. For LABEM I03, the highest production occurred at pH 5. High-performance liquid chromatography (HPLC) analyses were used to detect the production of surfactin and fengycin, which are biosurfactants from the lipopeptide class, by LABEM I01, LABEM I02, and LABEM I03. The HPLC results showed that LABEM I01 and LABEM I02 produce the lipopeptide fengycin. However, surfactin production was not detected in any of the strains. Regarding the genomic analysis of LABEM I01, LABEM I02, and LABEM I03, Average Nucleotide Identity (ANI) and Digital DNA-DNA Hybridization (dDDH) analyses revealed that LABEM I01 and LABEM I02 represent new species of the Paenibacillus genus, while LABEM I03 represents a new species of the Psychrobacillus genus. All strains harbored genes related to biosurfactant and/or bioemulsifier production. Although genes associated with lipopeptide production were found in LABEM I01 and LABEM I02, LABEM I03 only presented genes linked to exopolysaccharide production. Additionally, the results showed that LABEM I02 possesses genes encoding the production of 2,3-butanediol, a metabolite of significant biotechnological value. Thus, the findings of this study demonstrate that LABEM I01, LABEM I02, and LABEM I03, in addition to their biosurfactant and/or bioemulsifier production capabilities, hold potential applications in various biotechnological processes. Our results particularly highlight the biotechnological relevance of new bacterial species belonging to the Paenibacillus and Psychrobacillus genera. Publisher: Universidade Federal do Rio de Janeiro Type: Tese Thu, 27 Mar 2025 00:00:00 GMT http://hdl.handle.net/11422/28657 2025-03-27T00:00:00Z