Heterologous expression and characterization of cellulases identified in the transcriptome of termites for potential application in the production of bioethanol

• Grant number: 22/14889-9
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: August 01, 2023
• End date: November 30, 2026
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Principal Investigator: Anderson Ferreira da Cunha
• Grantee: Olinda Soares Athaide Alcobaça
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

Renewable energy sources are an alternative to reduce dependence on fossil fuels. In line with this, there is bioethanol, which is produced in a conventional way (1G) or from lignocellulosic residues (2G) generated by the agroindustry. This biomass is rich in cellulose and can be hydrolyzed into a substrate for fermentation. However, due to the high cost of enzymatic hydrolysis, this alternative has been economically unattractive. One possibility to make it viable would be to integrate the hydrolysis and fermentation steps by the process of Saccharification and Simultaneous Fermentation (SSF). However, commercially available enzymes are functional at temperatures incompatible with the fermentation process, making it an important bottleneck for implementing this technology. Thus, studies to identify efficient cellulolytic enzymes at temperatures close to fermentation temperatures are necessary for optimizing bioethanol production. For this purpose, our group has been analyzing data from the transcriptome of termites, including Heterotermes tenuis, due to the possibility of detecting lignocellulolytic enzymes for biotechnological application, considering that these insects are specialized in the degradation of lignocellulose, foraging at night and not thermoregulate. Additionally, H. tenuis is a pest of sugarcane, the main raw material for obtaining ethanol in the country. These characteristics highlight them as interesting targets for bioprospecting for efficient enzymes at lower temperatures. In a preliminary analysis, possible coding regions of three cellulases were identified, namely: beta-1,4-endoglucanase, cellobiohydrolase, and beta-glucosidase. In this sense, this work proposes to identify these transcripts, perform the cloning and heterologous expression of these enzymes in the yeast Pichia pastoris, as well as the biochemical and functional characterization to evaluate the potential of application in enzymatic cocktails for use in the production of bioethanol. (AU)