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This invention involves the production of TAGs containing 16-18 carbon fatty acid chains from a mutant strain of Rhodococcus opacus PD630. The mutant PD630 strain described in this invention metabolizes xylose in basic growth medium, without the addition of antibiotics such as gentamicin to induce xylose fermentation. By using a particular combination of bacterial titer, agitation speed, oxygen content, glucose concentration, nitrogen concentration, and carbon to nitrogen ratio to grow the mutant PD630 strain, TAG yield can be upwards of 50% of the total bacterial cell dry weight. Any common aerated reaction vessel can be used to grow PD630, and any common means of TAG purification can be used to harvest the TAGs. In addition to the discovery of the mutant strain of PD630, this invention also includes a simple method involving the combination of lignocellulose material derived from corn stover and sorghum silage to manufacture xylose. This method bypasses the need to use fermentation-inhibiting substances such phenols or furans, which would otherwise decrease the TAG yield.