Conversion of biomass-derived oligosaccharides into lipids

Area of Science:

• Biotechnology
• Microbiology
• Biochemistry

Background:

• Lignocellulosic biomass hydrolysis yields monosaccharides and oligosaccharides (oligocelluloses, oligoxyloses).
• Efficient utilization of these oligosaccharides is crucial for biorefinery applications.
• Identifying microorganisms capable of converting oligosaccharides to valuable products is essential.

Purpose of the Study:

• To investigate the oleaginous yeast Cryptococcus curvatus's ability to utilize oligocelluloses and oligoxyloses.
• To determine the efficiency of microbial lipid production from these oligosaccharides.
• To elucidate the mechanism of oligosaccharide assimilation and hydrolysis in C. curvatus.

Main Methods:

• Cultivation of C. curvatus with oligocelluloses and oligoxyloses as sole carbon sources.
• Quantification of microbial lipid content and lipid coefficient.
• Ion chromatography to analyze assimilated oligocelluloses.
• Investigation of simultaneous saccharification and lipid production processes.

Main Results:

• C. curvatus demonstrated utilization of both oligocelluloses and oligoxyloses for lipid production.
• Lipid content reached 35.9% and lipid coefficients were 0.20 g/g (oligocelluloses) and 0.17 g/g (oligoxyloses).
• Oligocelluloses with a degree of polymerization from 2 to 9 were assimilated, suggesting intracellular hydrolysis by inducible enzymes.

Conclusions:

• C. curvatus can directly assimilate and metabolize biomass-derived oligocelluloses and oligoxyloses.
• Intracellular hydrolysis of oligosaccharides by C. curvatus occurs via inducible cytoplasmic enzymes.
• Simultaneous saccharification and lipid production is feasible without cellobiase, indicating efficient in situ oligosaccharide utilization and potential cost reduction.