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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

Time course of oligoxylose consumption by C. curvatus. (A) Total sugars consumption. (B) Ion chromatogram of oligoxyloses consumption. C. curvatus cells were cultured at 30°C, 200 rpm for 72 h, and initial oligoxyloses concentration was 20 g total sugar/L.
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Figure 2: Time course of oligoxylose consumption by C. curvatus. (A) Total sugars consumption. (B) Ion chromatogram of oligoxyloses consumption. C. curvatus cells were cultured at 30°C, 200 rpm for 72 h, and initial oligoxyloses concentration was 20 g total sugar/L.

Mentions: Oligoxyloses were also utilized by C. curvatus (Figure 2). About 8.8 g/L of total sugars were consumed during the first 24 h, and almost no further consumption occurred from 24 h to 72 h (Figure 2A). IC results indicated that C. curvatus selectively utilized oligosaccharides with lower DPs in the sample. Those with retention time less than 10 min were consumed while others apparently remained intact during the first 24 h (Figure 2B), suggesting that oligoxyloses with higher DPs were difficult substrates for C. curvatus. After 72 h, residual sugar, cell mass, lipid content and lipid coefficient were 9.1 g/L, 5.4 g/L, 30.3% and 0.17 g/g consumed sugar, respectively (Table 1). These data suggest that C. curvatus is able to realize a comparable lipid coefficient on oligoxyloses to that achieved by the oleaginous yeast Trichosporon cutaneum on xylose[30].


Conversion of biomass-derived oligosaccharides into lipids.

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

Time course of oligoxylose consumption by C. curvatus. (A) Total sugars consumption. (B) Ion chromatogram of oligoxyloses consumption. C. curvatus cells were cultured at 30°C, 200 rpm for 72 h, and initial oligoxyloses concentration was 20 g total sugar/L.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Time course of oligoxylose consumption by C. curvatus. (A) Total sugars consumption. (B) Ion chromatogram of oligoxyloses consumption. C. curvatus cells were cultured at 30°C, 200 rpm for 72 h, and initial oligoxyloses concentration was 20 g total sugar/L.
Mentions: Oligoxyloses were also utilized by C. curvatus (Figure 2). About 8.8 g/L of total sugars were consumed during the first 24 h, and almost no further consumption occurred from 24 h to 72 h (Figure 2A). IC results indicated that C. curvatus selectively utilized oligosaccharides with lower DPs in the sample. Those with retention time less than 10 min were consumed while others apparently remained intact during the first 24 h (Figure 2B), suggesting that oligoxyloses with higher DPs were difficult substrates for C. curvatus. After 72 h, residual sugar, cell mass, lipid content and lipid coefficient were 9.1 g/L, 5.4 g/L, 30.3% and 0.17 g/g consumed sugar, respectively (Table 1). These data suggest that C. curvatus is able to realize a comparable lipid coefficient on oligoxyloses to that achieved by the oleaginous yeast Trichosporon cutaneum on xylose[30].

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