Evaluating feeding strategies for microbial oil production from glycerol by Rhodotorula glutinis

Abstract

Oil production, from biodiesel by‐product glycerol, through microbial fermentation provides a promising option as part of an integrated biorefinery process. However, bioprocessing improvements are required to make the process more efficient. In the present work, different glycerol feeding strategies were evaluated under fed‐batch cultivation of the oleaginous yeast Rhodotorula glutinis. Results showed that the concept of targeting first a cell proliferation stage and then a lipid accumulation stage had beneficial effects on both biomass and oil yields. Continual feeding and pulsed feedings, delivering the same total amount of nutrients, resulted in similar values of cellular biomass (∼25 g/L) and oil content (∼40%). In contrast, continual supply of nutrients at higher rates ( >0.8 g/L/h) led to an increase in both cell densities (30 g/L) and oil content (53%), attaining a high oil yield of 16.28 g/L. This suggests that a continual cultivation with two different rates for each stage constitutes an efficient approach to enhance microbial oil production.

Lipids from yeasts and fungi: physiology, production and analytical considerations

“…, ; Karamerou et al . ). It is evident that as far as the synthesis of SCO that is aimed to be transformed in second‐generation biodiesel is concerned, only hydrophilic carbon sources (i.e.…”

“…; Karamerou et al . ). On the other hand, given that it was desirable to elucidate this ‘interplay’ between the synthesis of storage lipid and citric acid on media enabling the de novo lipid accumulation in Y. lipolytica , it has recently been demonstrated that cultivation of this yeast strain on double‐limited media (i.e.…”

“…T. elegans 14Á9 3 4 Á5 Flasks Zikou et al (2013) interesting alternative to the use of plant oils for biodiesel production because oleaginous yeasts, due to their unicellular morphology can be cultivated more easily than the fungi in large-scale bioreactors, whereas strains of these yeasts can transform a variety of substrates including low-or even zero-cost materials to SCO, which can then be transformed to biodiesel (Xue et al 2006;Li et al 2007;Zhao et al 2008;Li et al 2010;Xu et al 2012Xu et al , 2013Xu et al , 2016Xu et al , 2017Tsakona et al 2014Tsakona et al , 2016Karamerou et al 2015;Louhasakul and Cheirsilp, 2013;Tchakouteu et al 2015aTchakouteu et al , 2017Karamerou et al 2017). It is evident that as far as the synthesis of SCO that is aimed to be transformed in second-generation biodiesel is concerned, only hydrophilic carbon sources (i.e.…”

Improved electrocompetence and metabolic engineering of Clostridium pasteurianum reveals a new regulation pattern of glycerol fermentation

“…Among others the microbial production of 1,3‐propanediol (PDO) and n ‐butanol has received particular attention and is industrially used . They can be produced from fermentations of glycerol – a byproduct from biodiesel production ‐ and sugars, e.g. using Clostridia .…”

“…Among others the microbial production of 1,3-propanediol (PDO) and n-butanol has received particular attention and is industrially used [1][2][3][4][5][6][7][8]. They can Abbreviations: C. pasteurianum, Clostridium pasteurianum; PDO, 1,3-propanediol; gRNA, guide RNA; MFA, metabolic flux analysis; SNPs, single-nucleotide polymorphisms be produced from fermentations of glycerol -a byproduct from biodiesel production [9][10][11] -and sugars, e.g. using Clostridia [12][13][14][15][16][17].…”