The microalgae Chlamydomonas reinhardtii as a platform for expression and secretion of recombinant β-glycosidases involved in the production of cellulosic ethanol

Author: Raíza dos Santos Azevedo (Currículo Lattes)
Supervisor: Dr Luis Fernando Fernandes Marins

Abstract

The high consumption of fossil fuels is considered the factor responsible for most of the environmental crises. Research related to the development of new technologies for the production of energy from biomass appears as an alternative to the use of these types of fuels. In view of the current scenario, the production of energy from lignocellulosic biomass (bagasse and straw) has been gaining prominence in the face of the off-season problem of sugar cane, where ethanol production is zero. The use of recombinant protein bio-factories, based on microalgae, for the production of large amounts of β-glycosidases, may allow the use of lignocellulosic biomass from the residues generated in the production of ethanol. To make recombinant protein production more efficient,it is possible to improve its ribosomal translation through codon optimization, increasing the translation rates of the protein of interest. To this end, the work proposes the use of Chlamydomonas reinhardtii as a production platform along with the optimization of codons to enhance the production and secretion of recombinant β-glucosidases, in large quantities, which degrade the sugarcane bagasse for the production of lignocellulosic ethanol . The main objectives of this study are: (i) To produce genetic constructs for the expression and secretion of two β-glucosidases of prokaryotic origin; (ii) Genetically transform the microalgae C. reinhardtii through electroporation and select highly productive clones; (iii) Determine the activity of β-glycosidases produced by genetically modified clones of C.reinhardtii aiming to select the most productive ones; and (iv) To test the efficiency of recombinant β-glycosidases in the degradation of cellobiose from cellulose from sugarcane bagasse. This model could work as a low-cost bio-factory, in addition to reducing the environmental impact caused by the carbon emission of sugar-energy plants since the cultivation of microalgae could take advantage of the carbon emissions generated by the plant itself.

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