Results
Utilization of a glucose:xylose mixture for lipid
production by T. cutaneum
The experiments started with cultivation of T. cutaneum
using a mixture of 47 g/L glucose and 23 g/L xylose as
the carbon source in a phosphate-buffered solution at
pH 5.5 to 6.0. Small amounts of yeast extract and
NH4Cl were included in the medium to achieve an
initial carbon:nitrogen (C:N) ratio of 351, a value very
close to the optimal value of 420 for lipid production by
the yeast R. toruloides [20]. After cultivation of T. cutaneum
for 120 hours, the culture produced 23.8 g/L cell
mass with a cellular lipid content of 49.7%, comparable
with earlier results in which both glucose and xylose
were present in the medium [12,21]. Although a higher
C:N ratio favors lipid accumulation [20,21], further
increases in the C:N ratio led to a much slower cell
growth and almost no further improvement in cellular
lipid content