Rhodotorula toruloides Single Cell Oil Production Using Eucalyptus urograndis Hemicellulose Hydrolysate as a Carbon Source

Helberth Júnnior Santos Lopes,Everson Alves Miranda,Nemailla Bonturi

doi:10.3390/en13040795

Helberth Júnnior Santos Lopes, Everson Alves Miranda + Show 1 more

Open Access

https://doi.org/10.3390/en13040795

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Journal: Energies	Publication Date: Feb 12, 2020
Citations: 26	License type: CC BY 4.0

Affiliation: Universidade Estadual de Campinas, University of Tartu

Abstract

Microbial oil is a potential substitute for vegetable oils in the biodiesel industry. Efforts to obtain cheap carbon sources for the cultivation of lipid-producing microorganisms comprise an active research area. This work aimed to extract the hemicellulose fraction from Eucalyptus uograndis and to use its hydrolysate as a carbon source for Rhodotorula toruloides (an oleaginous yeast) cultivation for microbial oil production. Hemicellulose hydrothermal extractions were performed at different temperatures, times, and ratios of solid to liquid (S/L). Temperature and time showed a stronger effect on the solubilization of hemicellulose. Hemicellulose extraction at 155 °C, 195 min, and an S/L ratio of 1/2 resulted in a hydrolysate with a xylose content of 37.0 g/l. R. toruloides cultivation in this hydrolysate showed that initial pH had a strong influence on cell growth. At an initial pH of 6.2, cells grew to 6.0 g/l of biomass with a lipid content of 50%. Therefore, we believe that E. urograndis hemicellulose hydrolysate could be a potential substrate for R. toruloides for lipid production based on the biorefinery concept.

Highlights

The International Energy Outlook/2017 projected that world energy consumption could increase by 28% from 2015 to 2040, which would lead to higher fossil fuel utilization and intensify problems linked to its use, especially environmental ones [1]
Microbial oils are a potential alternative feedstock as they do not compete with the edible sectors and their production can be done in bioreactors and regardless of weather and geopolitical conditions [4]
R. toruloides was able to grow and produce SCO when cultivated using eucalyptus hemicellulose hydrolysate, showing that it has the potential to be a source of low-cost raw material for the biodiesel chain of production

Summary

Introduction

The International Energy Outlook/2017 projected that world energy consumption could increase by 28% from 2015 to 2040, which would lead to higher fossil fuel utilization and intensify problems linked to its use, especially environmental ones [1]. Microbial oils (single cell oil, SCO) are a potential alternative feedstock as they do not compete with the edible sectors and their production can be done in bioreactors (in areas an order of magnitude smaller than the area required for crop cultivation) and regardless of weather and geopolitical conditions [4]. Oleaginous microorganisms are those that can accumulate more than 20% of their dry mass in the form of lipids. When R. toruloides is cultivated with conventional sugars like glucose, the substrate can represent up to 70% of the operational cost [7]

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