(597f) Discovery of Metabolic Pathways for Conversion of Lignin-Derived Phenolics to Lipids in Cutaneotrichosporon Oleaginosus

Cutaneotrichosporon oleaginosus, previously known as Cryptococcus curvatus, is a non-model oleaginous yeast that is known for its ability to metabolize many alternative sugars, including xylose, and tolerate toxic lignocellulosic hydrolysate inhibitors such as 5-hydroxymethylfurfural (5-HMF) and furfural. We discovered C. oleaginosus also tolerates and metabolizes lignin-derived phenolics, highlighting this organisms’ potential to utilize all components of lignocellulosic biomass. C. oleaginosus is able to fully metabolize phenol, 4-hydroxybenzoic acid (pHBA), and resorcinol as sole carbon sources, as well as in co-utilization with glucose and xylose. Cells grow as robustly in pHBA and resorcinol as in glucose. Phenol caused an extended lag phase due to toxicity, but cells were able to achieve comparable biomass as cells in other carbon sources. We explored different feeding strategies to overcome aromatic toxicity and increased lipid accumulation to over 69% of biomass by weight. Aromatic metabolism is well-characterized across many organisms, however, there are many different mechanisms utilized between species. An initial BLAST analysis revealed ortho-cleavage may be the mechanism this yeast uses, but qPCR data was inconclusive. RNAseq data enabled analysis of all putative aromatic degradation genes, and revealed other participating genes that were missed by BLAST. Transcriptomic analyses facilitated pathway elucidation for aromatic metabolism in C. oleaginosus and improved the existing genome annotation significantly. These pathways are being confirmed using metabolomics data. Finally, we will discuss the development of genetic tools to rapidly engineer this non-model system for the production of novel fatty acids such as omega-3 fatty acids.