>The team of University of Illinois and Princeton University researchers created a cost-effective, end-to-end pipeline for this valuable organic acid by engineering a tough, acid-tolerant yeast as the fermenting agent, avoiding costly steps in downstream processing.

Seems like the most important part, they modified yeast to make it for them which can keep making the acid without needing to constantly adjust the pH to keep them alive, which introduces things that have to be removed later at great cost.