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Optimization of Rhodosporidium toruloides medium based in sugarcane bagasse hemicellulosic hydrolysate supplemented with glycerol and soybean molasses aiming microbial oil production  

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Author(s):
Vaz, Luisa Pires
Total Authors: 1
Document type: Master's Dissertation
Defense date:
Abstract

Biodiesel, which has vegetable oils as a raw material, is currently used as a substitute for diesel produced from petroleum due to sustainability and environmental issues. However, geographic and climatic variations and competition for agricultural area with food crops affect the availability and cost of the oil seeds used in its production process. Microbial oil (MO) produced by oleaginous microorganisms is a possible solution to overcome these problems. The yeast Rhodosporidium toruloides is one of these microorganisms. It can accumulate up to 70% of oil (dry mass base) in its cells and can grow in media made from biorefinery co-products, e.g., sugarcane bagasse hemicellulose hydrolysate (SCBHH). However, this hydrolysate has low carbon to nitrogen (C/N) ratio and contains inhibitors that do not favor growth and lipid production. The objective of this work was to optimize the SCBHH as a medium for the production of MO by R. toruloides CCT7815 strain supplementing it with glycerol, soybean molasses, and yeast extract, the first two being able to increase the C/N ratio of the medium. The optimized formulation contained 30 g/L of glycerol, 50 g/L of soybean molasses, 1.5 g/L of yeast extract, and 80% (v/v) non-detoxified SCBHH, besides the 1% micronutrient solution requirement. In this medium the cells were able to accumulate 44% of lipids (dry mass base) whereas the non-supplemented hydrolysate provided a lipid content of 26%, resulting in a 5-fold increase in lipid concentration. Also, the best inoculum phase and initial cell concentration to be used as inoculum were determined: deceleration phase and OD equal 1. Therefore, the addition of glycerol and soybean molasses is a simple strategy to improve production of MO by this R. toruloides strain in substrates with low C/N ratio (AU)

FAPESP's process: 16/10636-8 - From the cell factory to the Biodiesel-Bioethanol integrated biorefinery: a systems approach applied to complex problems in micro and macroscales
Grantee:Roberto de Campos Giordano
Support type: Program for Research on Bioenergy (BIOEN) - Thematic Grants