Oleaginous yeast production in culture medium containing sugarcane bagasse hydrolysate

Author(s)

Ruth Verónica Sierra Aristizábal

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Química
• Defense date: 2013-10-04

Examining board members

Telma Teixeira Franco; Everson Alves Miranda; Jaciane Lutz Ienczak

• Advisor: Cecília Sulzbacher Caruso; Telma Teixeira Franco

Abstract

Lignocellulosic materials, such sugar cane bagasse, as reported as potential feedstocks for production of second generation biofuels, through hemicellulose hydrolysates (H-H) extraction rich in xylose and the subsequent fermentation with oleaginous yeast for lipids production. In this regard, the objective of this study was to adapt the Lipomyces starkeyi DSM 70296 in culture media containing H-H of sugar cane bagasse. The H-H with 12 g/L of xylose, 2 g/L of glucose, 10 g/L acetic acid, 0.7 g/L of furfural and 1.3 g/L of HMF was obtained after seven sequential extraction steps of bagasse previously pretreated by steam explosion. The yeast was adapted by evolutionary engineering in culture medium containing increasing concentrations of H-H. As result, there was obtained the yeast adapted to culture medium containing 30% of H-H, which showed higher cell productivity (113.90 mg/L/h) and cell concentration (9.79 g/L) compared to not adapted strain (73.54 mg/L/h and 5.21 g/L, respectively). Fermentation in Bioreactor in synthetic medium and containing 30% of H-H medium showed maximum specific growth rate (?max) of 0.117 and 0.122 h-1, respectively. Through experimental design 23 was determined the effects of acetic acid, furfural and hydroxymethylfurfural (HMF) on growth and yield lipid yeast. As result, there was obtained that acetic acid had significant effect on kinetic parameters by increasing the duration of lag phase up to 34 hours, besides reduction of cell productivity (Px) and rate of substrate consumption (rs). Additionally positive synergistic effects were observed when acetic acid is found in culture media with furfural and HMF. Preliminary tests indicate the possibility of high levels of inhibition of products generated by lignin degradation at concentrations above 7.32 g/L (AU)

• FAPESP's process: 10/17508-9 - Production of oleaginous yeasts in culture medium and sugarcane hydrolizates
• Grantee: Ruth Veronica Sierra Aristizabal
• Support Opportunities: Scholarships in Brazil - Master