title: The growth of oleaginous Rhodotorula glutinis in an airlift bioreactor on crude glycerol through a non-sterile fermentation process.
abstract: While the use of oleaginous Rhodotorula glutinis as a feedstock for biodiesel production is an attractive idea, as it can avoid the pollutions associated with over-consumption of fossil fuels. Nevertheless, the related costs, including the energy required for sterilization, remain a barrier to commercialization. This study thus used a low-pH non-sterile medium, instead of a completely sterilized one, to grow R. glutinis in a 5-L airlift bioreactor. The results show that R. glutinis can grow well at a low pH level of 4.0 and without sterilization of the medium, producing a final biomass of 11.7 g/L. Nevertheless, such a low pH will lead to fewer total lipids accumulation, and so a two-stage process of pH control in a non-sterile batch was proposed. Even this two-stage pH operation was also able to produce a similar final biomass of 11.7 g/L. However, the batch with two-stage pH control had a far higher lipid content of 55 ± 4% as compared to that of 21 ± 3% in the batch grown at pH 4.0. This study shows the potential of the proposed non-sterile process with two-stage pH control applied to the growth of R. glutinis to enhance the total lipid accumulation.
authors.affiliation: Department of Chemical and Materials Engineering, Tunghai University, 407, Taichung, Taiwan, hwyen@thu.edu.tw.
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Yen
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Liao
authors.forename: Yi Xian
authors.initials: YX
authors.lastname: Liu
mesh_terms: D001487:Basidiomycota / Q000254:growth & development*; D019149:Bioreactors; D005990:Glycerol / Q000378:metabolism*; D050356:Lipid Metabolism
chemical_list: D005990:Glycerol