Adaptation Strategy to Increase the Tolerance of Scheffersomyces stipitis NRRL Y-7124 to Inhibitors of Sugarcane Bagasse Hemicellulosic Hydrolysate Through Comparative Studies of Proteomics and Fermentation

Author(s)

Biazi, Luiz E. ; Santos, Samantha C. ; Neto, Antonio A. Kaupert ; Sousa, Amanda S. ; Soares, Lauren B. ; Renzano, Eduardo ; Velasco, Juliana ; Rabelo, Sarita C. ; Costa, Aline C. ; Ienczak, Jaciane L.

• Document type: Journal article
• Source: BioEnergy Research; v. 15, n. 1, p. 14-pg., 2021-03-10.

Abstract

In this work, we propose an adaptation strategy for Scheffersomyces stipitis NRRL Y-7124 to increase its tolerance to inhibitors of hemicellulosic hydrolysates in the production of bioethanol. Sugarcane bagasse pretreated with 0.5% (v/v) of sulfuric acid at 140 degrees C for 15 min was used as feedstock. The microorganism was subjected to a cell recycle batch fermentation system with increased inhibitors pressure, characterized by five consecutive batches with 33% of hydrolysate, followed by five subsequent batches with 67% of hydrolysate. The remaining composition of the culture media for each sequential batch (necessary to complete 100% of carbohydrate content) was synthetic substrate. Finally, the strain was used in a fed-batch fermentation with 100% of hydrolysate, resulting in an adapted strain of S. stipitis at the end. In order to validate the adaptation strategy, the fermentative performances of the adapted and non-adapted strains were compared under different acetic acid concentrations using synthetic substrate. 0.7 g/L of acetic acid significantly affected the fermentative performance of the non-adapted strain, while for the adapted strain, this value was 3.7-fold higher (2.6 g/L), confirming the increased tolerance. Through proteomic analysis, genes related to the defense mechanisms of S. stipitis against oxidative stress due to the presence of inhibitory compounds were identified, which plays a key role on the comprehension of the cell adaptation metabolism. (AU)

• FAPESP's process: 14/01135-0 - Second generation bioethanol production in intensified bioreactors from improved Scheffersomyces stipitis by induced evolution
• Grantee: Samantha Christine Santos
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/14567-0 - Mathematical modeling of second generation bioethanol production with cell recycle by using the microorganisms Scheffersomyces stipitis and Spathaspora passalidarum
• Grantee: Luiz Eduardo Biazi
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 15/20630-4 - Biorefinery development integrated to a bioethanol sugar cane plant with zero CO2 emission: routes to convert renewable resources to bio-products and bio-electricity
• Grantee: Rubens Maciel Filho
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/04997-0 - Scheffersomyces stipitis and Spathaspora passalidarum wild type yeast assessment for second generation bioethanol production from bagasse sugarcarne hydrolyzates containing xylose and glucose
• Grantee: Jaciane Lutz Ienczak
• Support Opportunities: Regular Research Grants