Limits...
Evaluating the effects of biocompatible cholinium ionic liquids on microbial lipid production by Trichosporon fermentans.

Liu L, Hu Y, Wen P, Li N, Zong M, Ou-Yang B, Wu H - Biotechnol Biofuels (2015)

Bottom Line: Despite the reduction in lipid content, the lipid production by T. fermentans was improved in the presence of low concentrations of [Ch][Lys] (≤30 mM) and [Ch][Ser] (≤20 mM) due to the remarkable increase of biomass.However, the anions of [Ch][Lys] and [Ch][Ser] could be assimilated as nitrogen source by T. fermentans and the reduced C/N ratio accounts for the inhibition of lipid accumulation, which could be alleviated by improving C/N ratio of medium.The anions of [Ch][Lys], [Ch][Ser] and [Ch][OAc] play an important role in affecting the cell growth and lipid accumulation of T. fermentans, and the inhibition of these three ILs on lipid production can be alleviated by careful fermentation condition control.

View Article: PubMed Central - PubMed

Affiliation: School of Biosciences and Bioengineering, Guangzhou Higher Education Mega Centre, South China University of Technology, 382 East Waihuan Rd., Panyu District, Guangzhou, 510640 China.

ABSTRACT

Background: Microbial lipid is a potential raw material for large-scale biodiesel production and lignocellulosic hydrolysate has been considered as promising low-cost substrate for lipid fermentation. Lignocellulosic biomass needs to be pretreated before enzymatic hydrolysis, and biocompatible cholinium ionic liquids (ILs) have been demonstrated to be highly efficient for pretreatment. However, the impact of these ILs residues in hydrolysates on downstream biotransformation remains unknown. Therefore, the influence of three typical cholinium ILs on the lipid production by Trichosporon fermentans was first investigated.

Results: The cell growth of T. fermentans was stimulated in the presence of cholinium lysine ([Ch][Lys]) and cholinium serine ([Ch][Ser]), while the lipid accumulation was inhibited by [Ch][Lys]) and [Ch][Ser]. Both cell growth and lipid accumulation of T. fermentans were inhibited in the presence of cholinium acetate ([Ch][OAc]). Despite the reduction in lipid content, the lipid production by T. fermentans was improved in the presence of low concentrations of [Ch][Lys] (≤30 mM) and [Ch][Ser] (≤20 mM) due to the remarkable increase of biomass. It was found that cholinium cation had minor influence on lipid production. However, the anions of [Ch][Lys] and [Ch][Ser] could be assimilated as nitrogen source by T. fermentans and the reduced C/N ratio accounts for the inhibition of lipid accumulation, which could be alleviated by improving C/N ratio of medium. In addition, the anion of [Ch][OAc] could be metabolized by T. fermentans, leading to a rapid alkaline-pH shift and strong inhibition of lipid production. And this inhibitory effect on lipid production could be significantly reduced by controlling culture pH.

Conclusions: The anions of [Ch][Lys], [Ch][Ser] and [Ch][OAc] play an important role in affecting the cell growth and lipid accumulation of T. fermentans, and the inhibition of these three ILs on lipid production can be alleviated by careful fermentation condition control. Hence, T. fermentans is a promising strain for microbial lipid production from cholinium ILs-pretreated lignocellulosic hydrolysates.

No MeSH data available.


Related in: MedlinePlus

Chemical structures of the three cholinium ILs.
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Sch1: Chemical structures of the three cholinium ILs.

Mentions: Recently, Hou et al. [16, 17] and Ninomiya et al. [18] reported a type of novel renewable cholinium ILs as highly effective solvents for lignocellulosic biomass pretreatment. For example, when [Ch][Lys] was used for pretreatment of rice straw at 90°C for 5 h, sugar yields of 84% for glucose and 42.1% for xylose were achieved. As biomass pretreatment solvents, it is inevitable that ILs will be left over at various concentrations in the lignocellulosic hydrolysates. To understand the effect of ILs on the downstream biotransformation will be helpful in assessing the possibility of using ILs-pretreated lignocellulosic hydrolysates for biofuel production. However, to date, there is no report about the impacts of cholinium ILs on microbial production of bio-based products. Trichosporon fermentans is an oleaginous yeast which can efficiently produce lipid in detoxified lignocellulosic hydrolysates [19, 20]. In this work, the effects of three typical cholinium ILs with robust lignocellulose pretreatment capability (i.e. cholinium lysine ([Ch][Lys]), cholinium serine ([Ch][Ser]), and cholinium acetate ([Ch][OAc], as shown in Scheme 1) on the cell growth and lipid accumulation of T. fermentans were firstly investigated. To give a deep insight into the influential mechanism, the sugar metabolism of cells and the effects of cation and anions of cholinium ILs on lipid production were further analyzed. This study will provide some valuable information for efficient application of cholinium ILs-pretreated lignocellulosic hydrolysates in biorefinery processes, particularly in microbial lipid production.Scheme 1


Evaluating the effects of biocompatible cholinium ionic liquids on microbial lipid production by Trichosporon fermentans.

Liu L, Hu Y, Wen P, Li N, Zong M, Ou-Yang B, Wu H - Biotechnol Biofuels (2015)

Chemical structures of the three cholinium ILs.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4536777&req=5

Sch1: Chemical structures of the three cholinium ILs.
Mentions: Recently, Hou et al. [16, 17] and Ninomiya et al. [18] reported a type of novel renewable cholinium ILs as highly effective solvents for lignocellulosic biomass pretreatment. For example, when [Ch][Lys] was used for pretreatment of rice straw at 90°C for 5 h, sugar yields of 84% for glucose and 42.1% for xylose were achieved. As biomass pretreatment solvents, it is inevitable that ILs will be left over at various concentrations in the lignocellulosic hydrolysates. To understand the effect of ILs on the downstream biotransformation will be helpful in assessing the possibility of using ILs-pretreated lignocellulosic hydrolysates for biofuel production. However, to date, there is no report about the impacts of cholinium ILs on microbial production of bio-based products. Trichosporon fermentans is an oleaginous yeast which can efficiently produce lipid in detoxified lignocellulosic hydrolysates [19, 20]. In this work, the effects of three typical cholinium ILs with robust lignocellulose pretreatment capability (i.e. cholinium lysine ([Ch][Lys]), cholinium serine ([Ch][Ser]), and cholinium acetate ([Ch][OAc], as shown in Scheme 1) on the cell growth and lipid accumulation of T. fermentans were firstly investigated. To give a deep insight into the influential mechanism, the sugar metabolism of cells and the effects of cation and anions of cholinium ILs on lipid production were further analyzed. This study will provide some valuable information for efficient application of cholinium ILs-pretreated lignocellulosic hydrolysates in biorefinery processes, particularly in microbial lipid production.Scheme 1

Bottom Line: Despite the reduction in lipid content, the lipid production by T. fermentans was improved in the presence of low concentrations of [Ch][Lys] (≤30 mM) and [Ch][Ser] (≤20 mM) due to the remarkable increase of biomass.However, the anions of [Ch][Lys] and [Ch][Ser] could be assimilated as nitrogen source by T. fermentans and the reduced C/N ratio accounts for the inhibition of lipid accumulation, which could be alleviated by improving C/N ratio of medium.The anions of [Ch][Lys], [Ch][Ser] and [Ch][OAc] play an important role in affecting the cell growth and lipid accumulation of T. fermentans, and the inhibition of these three ILs on lipid production can be alleviated by careful fermentation condition control.

View Article: PubMed Central - PubMed

Affiliation: School of Biosciences and Bioengineering, Guangzhou Higher Education Mega Centre, South China University of Technology, 382 East Waihuan Rd., Panyu District, Guangzhou, 510640 China.

ABSTRACT

Background: Microbial lipid is a potential raw material for large-scale biodiesel production and lignocellulosic hydrolysate has been considered as promising low-cost substrate for lipid fermentation. Lignocellulosic biomass needs to be pretreated before enzymatic hydrolysis, and biocompatible cholinium ionic liquids (ILs) have been demonstrated to be highly efficient for pretreatment. However, the impact of these ILs residues in hydrolysates on downstream biotransformation remains unknown. Therefore, the influence of three typical cholinium ILs on the lipid production by Trichosporon fermentans was first investigated.

Results: The cell growth of T. fermentans was stimulated in the presence of cholinium lysine ([Ch][Lys]) and cholinium serine ([Ch][Ser]), while the lipid accumulation was inhibited by [Ch][Lys]) and [Ch][Ser]. Both cell growth and lipid accumulation of T. fermentans were inhibited in the presence of cholinium acetate ([Ch][OAc]). Despite the reduction in lipid content, the lipid production by T. fermentans was improved in the presence of low concentrations of [Ch][Lys] (≤30 mM) and [Ch][Ser] (≤20 mM) due to the remarkable increase of biomass. It was found that cholinium cation had minor influence on lipid production. However, the anions of [Ch][Lys] and [Ch][Ser] could be assimilated as nitrogen source by T. fermentans and the reduced C/N ratio accounts for the inhibition of lipid accumulation, which could be alleviated by improving C/N ratio of medium. In addition, the anion of [Ch][OAc] could be metabolized by T. fermentans, leading to a rapid alkaline-pH shift and strong inhibition of lipid production. And this inhibitory effect on lipid production could be significantly reduced by controlling culture pH.

Conclusions: The anions of [Ch][Lys], [Ch][Ser] and [Ch][OAc] play an important role in affecting the cell growth and lipid accumulation of T. fermentans, and the inhibition of these three ILs on lipid production can be alleviated by careful fermentation condition control. Hence, T. fermentans is a promising strain for microbial lipid production from cholinium ILs-pretreated lignocellulosic hydrolysates.

No MeSH data available.


Related in: MedlinePlus