Investigation of CO2 capture by Clostridium beijerinckii employing bicarbonate as an inorganic carbon source

• Grant number: 23/10957-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2023
• End date: December 31, 2024
• Field of knowledge: Biological Sciences - Biochemistry - Biochemistry of Microorganisms
• Principal Investigator: Valeria Reginatto Spiller
• Grantee: Maria Eduarda Monzani Gomes
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil
• Associated scholarship(s): 24/04309-0 - Overexpression of the gene encoding the carbonic anhydrase enzyme by transformation of a Clostridium beijerinckii strain, BE.EP.IC

Abstract

Industrial progress has resulted in a larger emission of CO2, increasing the impact of global warming. An alternative is to employ CO2 as a carbon source in biotechnological processes, requiring microorganisms capable of capturing it, either through an autotrophic or mixotrophic metabolism, i.e., the concomitant assimilation of organic and inorganic carbon. In the literature it is reported that Clostridium beijerinckii ATCC 35702 has the ability to assimilate CO2, in combination with an organic carbon source, which seems to occur by three independent pathways: 1) via Wood-Ljungdahl; 2) via carbonic anhydrase; 3) by the reverse mechanism of pyruvate-ferredoxin oxidoreductase. Based on this, it seems that the C. beijerinckii Br21 strain, which was isolated in our laboratory, is able to perform this metabolism. So, this project proposes the investigation of the ability of this strain to capture CO2 as bicarbonate ion (HCO3-) provided as NaHCO3, in presence of glucose and/or fructose as co-substrate. This investigation will be carried out by means of an experimental design, whose variables are the culturing conditions; and the response, the concentration of butyric acid, the main product of the Br21 strain. Carbon will be quantified by a total organic carbon analyzer. Gene expression of the enzyme carbonic anhydrase or other enzyme related to inorganic carbon capture, will be quantified by qRT-PCR. Therefore, this project contributes to the development of technologies to reduce CO2, in line with the UN Sustainable Development Goals, especially SDG 13 - Action against global climate change, which seeks to combat the effects of climate change.