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Conversion of biomass-derived oligosaccharides into lipids.

Gong Z, Wang Q, Shen H, Wang L, Xie H, Zhao ZK - Biotechnol Biofuels (2014)

Bottom Line: Biomass hydrolysates usually contain monosaccharides as well as various amounts of oligosaccharides.C. curvatus can directly utilize biomass-derived oligosaccharides.Oligocelluloses are transported into the cells and then hydrolyzed by cytoplasmic enzymes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dalian National Laboratory for Clean Energy and Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China. zhaozb@dicp.ac.cn.

ABSTRACT

Background: Oligocelluloses and oligoxyloses are partially hydrolyzed products from lignocellulosic biomass hydrolysis. Biomass hydrolysates usually contain monosaccharides as well as various amounts of oligosaccharides. To utilize biomass hydrolysates more efficiently, it is important to identify microorganisms capable of converting biomass-derived oligosaccharides into biofuels or biochemicals.

Results: We have demonstrated that the oleaginous yeast Cryptococcus curvatus can utilize either oligocelluloses or oligoxyloses as sole carbon sources for microbial lipid production. When oligocelluloses were used, lipid content and lipid coefficient were 35.9% and 0.20 g/g consumed sugar, respectively. When oligoxyloses were used, lipid coefficient was 0.17 g/g consumed sugar. Ion chromatography analysis showed oligocelluloses with a degree of polymerization from 2 to 9 were assimilated. Our data suggested that these oligosaccharides were transported into cells and then hydrolyzed by cytoplasmic enzymes. Further analysis indicated that these enzymes were inducible by oligocelluloses. Lipid production on cellulose by C. curvatus using the simultaneous saccharification and lipid production process in the absence of cellobiase achieved essentially identical results to that in the presence of cellobiase, suggesting that oligocelluloses generated in situ were utilized with high efficiency. This study has provided inspiring information for oligosaccharides utilization, which should facilitate biorefinery based on lignocellulosic biomass.

Conclusions: C. curvatus can directly utilize biomass-derived oligosaccharides. Oligocelluloses are transported into the cells and then hydrolyzed by cytoplasmic enzymes. A simultaneous saccharification and lipid production process can be conducted without oligocelluloses accumulation in the absence of cellobiase by C. curvatus, which could reduce the enzyme costs.

No MeSH data available.


Related in: MedlinePlus

Microscopy analysis results. (A) Photograph under UV light at 365 nm. (B) Fluorescence microscopy image. A1 and B1, C. curvatus cell suspension; A2, MUG solution; A3 and B3, MUG-treated cell suspension; A4, supernatants from A3; A5, wet cells from A3 resuspended in buffer; A6, MUG-treated cell culture supernatants.
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Figure 4: Microscopy analysis results. (A) Photograph under UV light at 365 nm. (B) Fluorescence microscopy image. A1 and B1, C. curvatus cell suspension; A2, MUG solution; A3 and B3, MUG-treated cell suspension; A4, supernatants from A3; A5, wet cells from A3 resuspended in buffer; A6, MUG-treated cell culture supernatants.

Mentions: We further used 4-methylumbelliferyl-β-D-glucopyranoside (MUG) as a surrogate substrate to investigate the localization of hydrolytic enzymes produced by C. curvatus cells. When MUG was hydrolyzed, the product 4-methylumbelliferol was fluorescent. When observed under UV light at 365 nm, cells treated with MUG showed clear fluorescence whereas the supernatants had no such fluorescence (Figure 4A). Further, the treated cells showed up as blue, but cells without MUG treatment were not observed (Figure 4B). These results suggest that MUG was transported into cells and then hydrolyzed by intracellular β-glycosidic enzymes.


Conversion of biomass-derived oligosaccharides into lipids.

Gong Z, Wang Q, Shen H, Wang L, Xie H, Zhao ZK - Biotechnol Biofuels (2014)

Microscopy analysis results. (A) Photograph under UV light at 365 nm. (B) Fluorescence microscopy image. A1 and B1, C. curvatus cell suspension; A2, MUG solution; A3 and B3, MUG-treated cell suspension; A4, supernatants from A3; A5, wet cells from A3 resuspended in buffer; A6, MUG-treated cell culture supernatants.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3927853&req=5

Figure 4: Microscopy analysis results. (A) Photograph under UV light at 365 nm. (B) Fluorescence microscopy image. A1 and B1, C. curvatus cell suspension; A2, MUG solution; A3 and B3, MUG-treated cell suspension; A4, supernatants from A3; A5, wet cells from A3 resuspended in buffer; A6, MUG-treated cell culture supernatants.
Mentions: We further used 4-methylumbelliferyl-β-D-glucopyranoside (MUG) as a surrogate substrate to investigate the localization of hydrolytic enzymes produced by C. curvatus cells. When MUG was hydrolyzed, the product 4-methylumbelliferol was fluorescent. When observed under UV light at 365 nm, cells treated with MUG showed clear fluorescence whereas the supernatants had no such fluorescence (Figure 4A). Further, the treated cells showed up as blue, but cells without MUG treatment were not observed (Figure 4B). These results suggest that MUG was transported into cells and then hydrolyzed by intracellular β-glycosidic enzymes.

Bottom Line: Biomass hydrolysates usually contain monosaccharides as well as various amounts of oligosaccharides.C. curvatus can directly utilize biomass-derived oligosaccharides.Oligocelluloses are transported into the cells and then hydrolyzed by cytoplasmic enzymes.

View Article: PubMed Central - HTML - PubMed

Affiliation: Dalian National Laboratory for Clean Energy and Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian 116023, PR China. zhaozb@dicp.ac.cn.

ABSTRACT

Background: Oligocelluloses and oligoxyloses are partially hydrolyzed products from lignocellulosic biomass hydrolysis. Biomass hydrolysates usually contain monosaccharides as well as various amounts of oligosaccharides. To utilize biomass hydrolysates more efficiently, it is important to identify microorganisms capable of converting biomass-derived oligosaccharides into biofuels or biochemicals.

Results: We have demonstrated that the oleaginous yeast Cryptococcus curvatus can utilize either oligocelluloses or oligoxyloses as sole carbon sources for microbial lipid production. When oligocelluloses were used, lipid content and lipid coefficient were 35.9% and 0.20 g/g consumed sugar, respectively. When oligoxyloses were used, lipid coefficient was 0.17 g/g consumed sugar. Ion chromatography analysis showed oligocelluloses with a degree of polymerization from 2 to 9 were assimilated. Our data suggested that these oligosaccharides were transported into cells and then hydrolyzed by cytoplasmic enzymes. Further analysis indicated that these enzymes were inducible by oligocelluloses. Lipid production on cellulose by C. curvatus using the simultaneous saccharification and lipid production process in the absence of cellobiase achieved essentially identical results to that in the presence of cellobiase, suggesting that oligocelluloses generated in situ were utilized with high efficiency. This study has provided inspiring information for oligosaccharides utilization, which should facilitate biorefinery based on lignocellulosic biomass.

Conclusions: C. curvatus can directly utilize biomass-derived oligosaccharides. Oligocelluloses are transported into the cells and then hydrolyzed by cytoplasmic enzymes. A simultaneous saccharification and lipid production process can be conducted without oligocelluloses accumulation in the absence of cellobiase by C. curvatus, which could reduce the enzyme costs.

No MeSH data available.


Related in: MedlinePlus