Our Technology | Bioproduction
Our proprietary technology includes genetic sequences which, when placed in cells, allow the resulting transformed cells to fend off a variety of stresses that occur in the bioproduction process. This will enable these cells to produce more product (ethanol, enzyme, or pharmaceutical) than comparable cells lacking this genetic sequence.
We are targeting the production of fuel ethanol as our first application of this technology.
Fuel ethanol is produced by the fermentation of a carbohydrate substrate by yeast cells. In this process, yeast is severely inhibited in reaching its full productive potential by a variety of stresses including rising alcohol concentration, low pH, high temperature, bacterial contamination, and dissolved chemicals. We believe that yeast transformed with our genetic sequence will be able to fend off the effects of these stresses, enabling the yeast to maximize its ability to produce alcohol.
As a prelude to testing our sequences in the production of fuel ethanol, we subjected yeast transformed with several of our sequences to the surrogate stress of hydrogen peroxide (H2O2), which is highly toxic to living cells. In the following three examples, we show yeast transformed with our sequence iDi-032 tested against control yeast not containing the sequence. We demonstrated, as a base line, that yeast containing the iDi-032 gene grows at the same rate and produces relatively the same number of cells over a 48-hour time course as does the control yeast when there is no peroxide stress applied.
Yeast Cells Not Stressed with H2O2
When the experiment was repeated under the influence of 5mM H2O2, growth of both cell cultures was suppressed during the first 24 hours and then grew to different levels in the next 24 hours with the iDi-032 transformed cells growing to a cell count roughly 3x higher than the controls. During the first 24 hours, cell growth is highly suppressed in both cases because the peroxide was killing all inferior cells. Only the fittest cells survived the first 24 hours and they then went on to populate the culture during the next 24 hours. iDi-032 cells showed greater resistance to H2O2 during the first 24 hours and thus were able to out grow control cells over the next 24 hours.
Yeast Cells Stressed with 5mM H2O2
Repeating the experiment with 7.5mM H2O2 demonstrated that this level of stress was too great for any of the cells to overcome over the full duration of the experiment. However, it is interesting to note that even at greatly diminished levels during the first 6 hours, the cells containing the iDi-032 gene again outperformed the control cells.
Yeast Cells Stressed with 7.5mM H2O2
Based on these experiments, we are now optimizing the expression cassette used to drive our inserted genetic sequence. Once this is completed, we will test yeast transformed with several of our sequences to produce fuel ethanol at the lab bench level, and at 2- and 5-liter bioreactor levels. It is anticipated that this work will be completed in 2007. At that point, it will be ready to test under larger scale manufacturing conditions.