UCR graduate researcher Cory Schwartz and professor of chemical and environmental engineering Ian Wheeldon have expanded the way yeast can be manipulated through the Clustered Regularly Interspaced Short Palindromic Repeats gene editing system (CRISPR-CAS9). With this new system, biofuels, adhesives and fragrances can be mass produced at a cheaper cost.
This specific system performs at a more precise, effective and straightforward level when engineering the oil-producing yeast Yarrowia lipolytica. Current technology is ineffective due to imprecision, as it forces researchers to use trial and error to identify which locations of the yeast can be engineered.
Saccharomyces cerevisiae is generally the most researched and utilized yeast and found in bread and beer. Saccharomyces cerevisiae and Yarrowia lipolytica differ in their kind of metabolism. Yarrowia lipolytica can produce a lot more lipids like triglycerides — a component of natural fats and oils — thus it is an easier species to work with when trying to engineer even more lipids and transform them into invaluable products.
“Old methods of engineering Y. lipolytica are similar to taking a new machine and putting it at random places on the assembly line until you identify a location that works,” Schwartz explained. “This wastes time and money, as many different locations and possibilities for the new machine have to be tested before the best one is found. Using CRISPR-CAS9, the new machine can be placed in the correct location on the first try almost every time, allowing for more rapid improvement of the assembly line.” Their study with this specific yeast strain began in June 2014 and they employed CRISPR-CAS9 in November 2014.
Wheeldon, along with Schwartz and two other Clemson University contributors are hoping that their research will broaden the use of Yarrowia lipolytica and increase lipid and polymer precursor assemblies. “We anticipate that this CRISPR-CAS9 system will allow for more rapid and varied engineering of Y. lipolytica, and will make it an attractive host to a range of bio-manufacturing processes,” Schwartz said.
The team’s next step is to go beyond the Yarrowia lipolytica strain and develop other strains with the ability to create differing products like long-chain dicarboxylic acids, an antecedent acid to polymers and a key ingredient in petroleum.
“Currently, these molecules are produced from non-renewable raw materials derived from petroleum in processes that are inefficient and pose safety risks, so being able to produce them from cheap raw materials in a bio-manufacturing process is very appealing,” Wheeldon told UCR Today.