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Purification of biodiesel-derived crude glycerol by acidification to be used as

a carbon source for microbial oil production by oleaginous yeast

CHC28
Pseudozyma parantarctica

1,2
1,2
1
Chutima Rakkitkanphun , Dolnapa Kaewpa , Jantima Teeka , Atsadawut Areesirisuk 1,2,*

1 Division of Biology, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi, Pathum
Thani, Thailand, 40002
2 Center of Excellence in Nano-Biotechnology, Faculty of Science and Technology, Rajamangala University of
Technology Thanyaburi, Pathum Thani, Thailand, 4000
*Corresponding author: atsadawut_a@rmutt.ac.th
________________________________________________________________________________
Abstract

This research aimed to apply the acidification method to remove impurities from
biodiesel-derived crude glycerol (BCG) and investigate the potential of purified BCG (PBCG) to

be used as a carbon source for microbial oil production by oleaginous yeast Pseudozyma
parantarctica CHC28. The optimum purifying conditions of BCG were pretreated with

hydrochloric acid at a pH of 1.71. The PBCG concentration was 469.52 g/L under optimized

conditions. The batch fermentation was studied using a nitrogen-limited medium containing
PBCG (PBCG-medium). The PBCG-medium with 50 g of PBCG per liter provided the maximum

biomass and oil concentration of 11.10 g/L and 4.07 g/L, respectively. The oil accumulation
was approximately 45%. The long-chain fatty acids C16–C18 were the main compositions,

which accounted for over 85%. These results suggested that the conversion of PBCG into
microbial oil was an interesting direction to produce microbial oil. It was also a remarkable

solution to add value to the by-products of biodiesel production. The mathematical model
was demonstrated to describe satisfactorily the yeast growth and microbial oil production

profile achieved in media containing pure glycerol and PBCG as carbon sources.

Keywords: purification, biodiesel-derived crude glycerol, Pseudozyma parantarctica, microbial
oil, biodiese