The production of triacylglycerides (TAGs) from the fermentation of renewable biomass could serve as a cheap source of biodiesels and other fuels.
As our planet's fossil fuel supply is quickly diminishing, microbially derived biodiesels could play an important role as a renewable energy source. While microbes have already been shown to produce TAGs from the fermentation of refined carbon sources such as gluconate or olive oil, the processes to refine these carbon sources are often labor-intensive and expensive. An invention that includes both a biodiesel-producing microbe and a simple method for a refinement of xylose sugar from renewable crop sources would make microbially derived biodiesels much more economically feasible.
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.
- Economically feasible alternative source of renewable energy
- Cheap, easily implemented method of TAG production from bacteria
- Simple process to derive xylose sugar from crops
- >50% cell dry weight yield of TAGs