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| Author(s): |
Erick Giancarlo Suclupe Farro
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Carlos. |
| Institution: | Universidade de São Paulo (USP). Instituto de Física de São Carlos (IFSC/BT) |
| Defense date: | 2016-04-28 |
| Examining board members: |
Alessandro Silva Nascimento;
Júlio César Borges;
Fabio Marcio Squina
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| Advisor: | Alessandro Silva Nascimento |
| Abstract | |
Climate change is causing losses in different sectors of the world economy. At the meeting of COP21, focused on climate changes, participants from around the world decided to take urgent actions to try to halt the increase in global average temperature. Within this scenario, the production and consumption of energy are of central importance, where renewable energy sources have been preferred to fossil fuels. Brazil has an important role in the global renewable energy generation by contributing 40% of its total energy mix. The degradation of the components of plant cell wall has a vast potential in the generation of biofuels and other green chemical from cellulose, hemicellulose and lignin. Thus, studies of enzymes that degrade these components have been carried out, with emphasis on glycoside hydrolases. Among the hydrolases are the arabinanases, enzymes capable of hydrolyzing arabinan, a polysaccharide component of hemicellulose, in L-arabinose. In this work, studies involving two arabinanases from Bacillus licheniformis were carried out, starting in gene cloning step. The products were transformed into Escherichia coli, expressed and purified. The evaluation of the thermal stability of the enzymes showed an affinity for divalent metals. Crystallization attempts resulted in the formation of a single crystal, which made it possible to determine the crystal structure of one arabinanase. Through biochemical assays, it was determined the substrate specificity, optimum temperature and pH and activity against metals. It was observed that the enzymes are selective for non-branched arabinan, have optimum temperature at 45 and 40 degrees, to BlAbn-1 and BlAbn-2, respectively, and optimum pH of 8 and 7. Finally, additional tests were performed to evaluate the possible synergism and oxidative activity. Although the oxidative activity assays were inconclusive, the synergism tests showed that BlAbn-1 is able to increase by 30% the activity of the enzymatic cocktail Accellerase 1500 on pre-treated biomass and on pure cellulose. This effect is even greater in the presence of nickel sulfate. (AU) | |
| FAPESP's process: | 14/03768-0 - Search for structural templates for the engineering of catalytic functions |
| Grantee: | Erick Giancarlo Suclupe Farro |
| Support Opportunities: | Scholarships in Brazil - Master |