Search

Commercial cultivation of sugarcane is usually carried out by planting culm segments (sett) carrying buds in their internodes. However, this is an inefficient practice due to high sprouting irregularity. In this work, we inspect the first stages of the physiological preparation of the culm for sprouting, trying to identify compounds that actively participate in this process. We compared, during the first 48 h, the metabolic profile of sugarcane against energy cane, a cultivar known to have higher sprouting speed and consistency. In fact, during this short period it was possible to observe that energy cane already had a higher physiological activity than sugarcane, with significant changes in the catabolism of amino acids, increased levels of reducing sugars, lipids and metabolic activity in the phenylpropanoid pathway. On the other hand, sugarcane samples had just begun their activity during this same period, with an increase in the level of glutamate as the most significant change, which may be linked to the strategy of these cultivars to develop their roots before leaves, opposite of what is seen for energy cane. These results contribute to the development of strategies for increasing the efficiency of sprouting in sugarcane.

Energy cane is a bioenergy crop with an outstanding ability to bud sprouting and increasing yield in ratoon cycles even in marginal lands. Bud fate control is key to biomass production and crop profits due to vegetative propagation and tiller dependency, as well as phenotype plasticity to withstand harsh environmental conditions. During the establishment stage (plant cane cycle), energy cane has a tendency for low root:shoot ratio, which might hamper the ability to cope with stress. Auxin is known to modulate bud sprouting and stimulate rooting in sugarcane. Hence, we treated a slow and a fast bud sprouting energy cane cultivars with auxin or controls (with and without water soaking) for 6 h prior to planting and evaluate plant growth parameters and metabolic profiling using two techniques (gas chromatography with time-of-flight mass spectrometer and nuclear magnetic resonance) to characterize the effect and identify metabolite markers associated with bud inhibition and outgrowth. Auxin inhibited bud burst and promote rooting in setts changing the root:shoot ratio of plantlets. Metabolome allowed the identification of lactate, succinate and aspartate family amino acids as involved in bud fate control through the potential modulation of oxygen and energy status. Investigating environmental and biochemical factors that regulate bud fate can be incremental to other monocot species. Our study provides new insights into bud quiescence and outgrowth in cane hybrids, with the potential to leverage our understanding of yield-related traits, crop establishment and adaptation to global climate change.

Brazil was the first country to use bioethanol in large volumes, still in the 70′s, to cope with the oil crisis. The development of vehicles powered by ethanol included the biofuel definitively in the Brazilian energy matrix, ensuring its demand. To increase the ethanol production, a new cane variety has been developed, the energy cane, which can potentially triple the productivity of biomass per hectare and reduce the production costs. Since most of the sugar produced by energy cane is insoluble, second-generation mills have been installed in Brazil, and nowadays the technology is in a consolidation phase. To increase the stability of the biofuels market and to attend the Nationally Determined Contribution at COP21, Brazil has created the RenovaBio, a program by which the biofuels producers receive financial titles, the CBIOs, in the proportion of the biofuel production volume and efficiency, and under the condition of respecting the environmental legislation. Fuels distributors will have an obligation to buy CBIOs to compensate emissions beyond their mandates, but CBIOs will also be available to any interested investor, with significant potential for a strong appreciation. As a result, the expectation is to have a substantial increase in sustainable biofuels production, mainly ethanol, which could become a world commodity to supply international markets in the bioeconomy world.

The Polyploid Gene Assembler (PGA), developed and tested in this study, represents a new strategy to perform gene-space assembly from complex genomes using low coverage DNA sequencing. The pipeline integrates reference-assisted loci and de novo assembly strategies to construct high-quality sequences focused on gene content. Pipeline validation was conducted with wheat (Triticum aestivum), a hexaploid species, using barley (Hordeum vulgare) as reference, that resulted in the identification of more than 90% of genes and several new genes. Moreover, PGA was used to assemble gene content in Saccharum spontaneum species, a parental lineage for hybrid sugarcane cultivars. Saccharum spontaneum gene sequence obtained was used to reference-guided transcriptome analysis of six different tissues. A total of 39,234 genes were identified, 60.4% clustered into known grass gene families. Thirty-seven gene families were expanded when compared with other grasses, three of them highlighted by the number of gene copies potentially involved in initial development and stress response. In addition, 3,108 promoters (many showing tissue specificity) were identified in this work. In summary, PGA can reconstruct high-quality gene sequences from polyploid genomes, as shown for wheat and S. spontaneum species, and it is more efficient than conventional genome assemblers using low coverage DNA sequencing.

n-Butanol is a chemical widely used in industry, with an approximate annual output of 4 million tons and a market valued at USD 8.6 billion. It was first produced by ABE fermentation (acetone - n-butanol - ethanol) at the beginning of the twentieth century using molasses as a substrate, an expensive raw material that made the process economically unfeasible. In this work, we developed a second-generation fermentation process using cellulosic sugar as the substrate. A strain of Clostridium saccharoperbutylacetonicum has been evolved to n-butanol resistance, and we have found that the addition of xylooligosaccharides to the culture medium leads to a significant increase in the n-butanol yield and productivity. As a result, an n-butanol titer of 12.5 g/L and a productivity of 0.43 g/L.h were obtained, a respective gain of 17% and 58% relative to the initial process. These advances indicate that second-generation technologies can make viable the production of renewable n-butanol.

Sugarcane (Saccharum spp.) grows in all tropical and subtropical regions of the world, being cultivated in more than 100 countries. Modern cultivars are the results of interspecific crosses, having S. officinarum as the main genetic source, which results in high sucrose production. Energy cane is still a less rigorous definition, applied to cane cultivars that have higher biomass, although lower sucrose concentration. Despite the practical advance, little is known about the molecular and physiological basis of the energy cane productivity and robustness, a knowledge that can be very helpful for the development of cane varieties in general. In this work, we have explored the sprouting process, which is very irregular in sugarcane plantation and thereby a main cost factor. Our results could be summarized in three main contributions: first, we observed that energy cane has a physiological strategy very different from that one observed for sugarcane, starting with the shoot development and only thereafter beginning the root growth. After 10 days, the energy cane had a shoot height of 14.19 cm against of 4.24 cm of sugarcane. Nevertheless, we noticed the energy cane root presents a fast and vigorous development, overcoming the sugarcane root volume after 50 days, with 24.36 and 14.79 cm3, respectively. Second, we observed that the energy cane has homogeneity in the sprouting rate of the different internodes, regardless of their age. Finally, our data allowed us to propose that the greater growth seen in energy cane might be attributed to a vigorous rate of nocturnal growth with angulation in relation to the time of 11.89°, which is lower in sugarcane, with angulation of 5.47°.

There is a common concept in life: large and complex molecules result from the synthesis of units that are later joined together. Mankind learned this principle and employed it to develop language, culture, and technology. This same principle is applied in the petrochemical industry by fractionating the fossilized carbon chains into small molecules and then polymerizing them in order to develop synthetic polymers, which are much more flexible, resistant, and durable than natural polymers. Recent developments in molecular biology have opened the possibility of modifying organisms in order to create new biosynthetic routes for the production of monomers that would fit the biggest challenge in modern society: the production of high quality polymers from renewable feedstocks. This review focuses on the latest advances in molecular biology and the new knowledge and technologies that enable the possibility of converting cells into efficient and sustainable chemical reactors. The first examples of this technolog...

Nano-sized zinc oxide (ZnO) was prepared by metal organic chemical vapor deposition (MOCVD) in a sulfonated polystyrene matrix. The effects of ultraviolet light irradiation on the growth of ZnO was examined. Scanning electron microscopy (SEM) analysis reveal that the ZnO nanoparticles have polycrystalline hexagonal wurtzite structure. The photodeposited films showed lower resistivities relatively to the nonirradiated films at 150 8C. Quantum chemistry was used to investigate the possible reactions of diethylzinc (DEZ) on PS-SO3H surface. The semiempirical simulations at PM3 level indicates strong interactions of DEZ with the polymeric surface and may be able to explain the growth of the highly crystalline ZnO on the polymeric substrate, as observed experimentally. # 2004 Elsevier B.V. All rights reserved.

Background Synthetic biology allows the development of new biochemical pathways for the production of chemicals from renewable sources. One major challenge is the identification of suitable microorganisms to hold these pathways with sufficient robustness and high yield. In this work we analyzed the genome of the propionic acid producer Actinobacteria Propionibacterium acidipropionici (ATCC 4875). Results The assembled P. acidipropionici genome has 3,656,170 base pairs (bp) with 68.8% G + C content and a low-copy plasmid of 6,868 bp. We identified 3,336 protein coding genes, approximately 1000 more than P. freudenreichii and P. acnes, with an increase in the number of genes putatively involved in maintenance of genome integrity, as well as the presence of an invertase and genes putatively involved in carbon catabolite repression. In addition, we made an experimental confirmation of the ability of P. acidipropionici to fix CO2, but no phosphoenolpyruvate carboxylase coding gene was found in the genome. Instead, we identified the pyruvate carboxylase gene and confirmed the presence of the corresponding enzyme in proteome analysis as a potential candidate for this activity. Similarly, the phosphate acetyltransferase and acetate kinase genes, which are considered responsible for acetate formation, were not present in the genome. In P. acidipropionici, a similar function seems to be performed by an ADP forming acetate-CoA ligase gene and its corresponding enzyme was confirmed in the proteome analysis. Conclusions Our data shows that P. acidipropionici has several of the desired features that are required to become a platform for the production of chemical commodities: multiple pathways for efficient feedstock utilization, ability to fix CO2, robustness, and efficient production of propionic acid, a potential precursor for valuable 3-carbon compounds.

Orientadores: Gonçalo Amarante Guimarães Pereira, Johana Rincones Perez Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia Resumo: O resumo poderá ser visualizado no texto completo da tese digital Abstract: The abstract is available with the full electronic document Doutorado Genética de Microorganismos Doutor em Genética e Biologia Molecular