About

Christopher V. Rao is a professor in the Department of Bioengineering at the University of Illinois Urbana-Champaign. His primary research interests include systems and synthetic biology, with a focus on synthetic bioengineering. His work involves exploiting genetic and physiological variation in microbes to reveal enzyme functions, engineering microorganisms for lipid overproduction, and developing metabolic engineering strategies for various biotechnological applications. Rao has contributed to understanding microbial growth, gene expression, and metabolic pathways, advancing the field of bioengineering through his research. He holds a Ph.D. from the University of Wisconsin and completed a postdoctoral fellowship at the University of California, Berkeley. His academic and research career is distinguished by numerous awards and recognition for his contributions to bioengineering.

Research topics

• Engineering
• Pulp and paper industry
• Biotechnology
• Environmental science
• Chemistry
• Agronomy
• Waste management
• Biology
• Ecology
• Food science
• Economics
• Biochemical engineering

Selected publications

• RT-EZ: A Golden Gate Assembly Toolkit for Streamlined Genetic Engineering of <i>Rhodotorula toruloides</i>

  ACS Synthetic Biology · 2025-04-15 · 8 citations

  articleOpen accessCorresponding

  For economic and sustainable biomanufacturing, the oleaginous yeast Rhodotorula toruloides has emerged as a promising platform for producing biofuels, pharmaceuticals, and other valuable chemicals. However, genetic manipulation of R. toruloides has been limited by its high GC content and the lack of a replicating plasmid, necessitating gene integration into the genome of the yeast. To address these challenges, we developed the RT-EZ (R. toruloides Efficient Zipper) toolkit, a versatile tool based on Golden Gate assembly, designed to streamline R. toruloides engineering with improved efficiency and flexibility. The RT-EZ toolkit simplifies vector construction by incorporating new features such as bidirectional promoters and 2A peptides, color-based screening using RFP, and sequences optimized for both Agrobacterium tumefaciens-mediated transformation (ATMT) and easy linearization, enabling straightforward selection and transformation. Notably, the RT-EZ kit can be used to construct an expression cassette with four different genes in one assembly reaction, significantly improving vector construction speed and efficiency. The utility of the RT-EZ toolkit was demonstrated through the successful synthesis of arachidonic acid in R. toruloides by coexpressing fatty acid elongases and desaturases. This result underscores the potential of the RT-EZ toolkit to advance synthetic biology in R. toruloides, providing a streamlined method for addressing genetic engineering challenges in the yeast.

  PublisherOA PDFDOI

• A Unifying Equation for Fermentation Sustainability across the Titer-Rate-Yield Landscape

  ChemRxiv · 2025-11-12

  article

  Industrial fermentation underpins the global bioeconomy and is central to the sustainable production of fuels and chemicals. While commercial viability hinges on improvements in fermentation titer, rate, and yield (TRY), generalizable insight into how fermentation performance influences system cost remains elusive due to complex interactions among feedstocks, fermentation, separations, catalytic upgrading, waste management, and other decisions across diverse biomanufacturing facility designs. Here, we systematically mapped the entire theoretical fermentation performance spaces (formed by all potential combinations of TRY) for 32 representative biomanufacturing facilities—spanning distinct choices for feedstocks, fermentation regimes and products, separations, and catalytic upgrading—by simulating and evaluating them (by techno-economic analysis, TEA) under uncertainty (e.g., 600,000 Monte Carlo simulations) and across TRY combinations (e.g., 7,500 TRY combinations for 32 configurations). Strikingly, across this wide design and thermodynamic simulation space, the relationship between fermentation TRY and system cost could be captured with a simple, generalizable mathematical equation (R2 of 0.992−1.000 across our simulations; 0.954−1.000 when validated against prior studies that used different tools). We leveraged the proposed mathematical equation to elucidate key drivers—among biomanufacturing facility design decisions and uncertainties in technological and contextual parameters—that shape cost sensitivity to fermentation performance, generating widely applicable insights. By demonstrating that a unifying relationship governs the impact of fermentation on biomanufacturing economics, this work establishes a foundation for more agile, holistically predictive, and resource-efficient strategies to prioritize fermentation research and development needs and accelerate the commercialization of emerging fermentation technologies.

  PublisherDOI

• Lipid accumulation in nitrogen and phosphorus-limited yeast is caused by less growth-related dilution

  Metabolic Engineering · 2025-08-22 · 6 citations

  articleOpen access
  PublisherOA PDFDOI

• Extracellular polyol esters of fatty acids by Rhodotorula yeast for streamlined biorefineries

  Trends in biotechnology · 2025-06-09 · 1 citations

  reviewSenior author
  PublisherDOI

• N-Acetyl cysteine exhibits antimicrobial and anti-virulence activity against Salmonella enterica

  PLoS ONE · 2025-01-07 · 3 citations

  articleOpen accessSenior authorCorresponding

  Salmonella enterica is a common foodborne pathogen that causes intestinal illness varying from mild gastroenteritis to life-threatening systemic infections. The frequency of outbreaks due to multidrug-resistant Salmonella has been increased in the past few years with increasing numbers of annual deaths. Therefore, new strategies to control the spread of antimicrobial resistance are required. In this work, we found that N-acetyl cysteine (NAC) inhibits S. enterica at MIC of 3 mg ml-1 and synergistically activates the bactericidal activities of common antibiotics from three-fold for ampicillin and apramycin up to1000-fold for gentamycin. In addition, NAC inhibits the expression of virulence genes at sub-inhibitory concentrations in a dose-dependent manner. The whole-genome sequencing revealed that continuous exposure of S. enterica to NAC leads to the development of resistance; these resistant strains are attenuated for virulence. These results suggest that NAC may be a promising adjuvant to antibiotics for treating S. enterica in combination with other antibiotics.

  PublisherDOI

• Selective designer hydrolysates preparation from the Miscanthus bioenergy crop for microbial lipid production: A way forward for sustainable biorefinery advancements

  SSRN Electronic Journal · 2025-01-01

  preprintOpen access
  PublisherDOI

• Protoplast fusion as a strategy to increase ploidy in <i>Rhodotorula toruloides</i> for strain development

  Journal of Industrial Microbiology & Biotechnology · 2025-12-09

  articleOpen access

  Rhodotorula toruloides is a red oleaginous yeast with growing commercial interest because of its hardiness and exceptional lipid production capacity. Because it is a basidiomycete yeast with a complex life cycle, many of the classical breeding methods used with ascomycetes are unavailable for strain improvement. However, we have been able to construct polyploid yeast by fusing protoplasts of parents with the same mating type. Fusing of Y-6985 (A2) and Y-48190 (A2), which had been transformed with complementary antibiotic markers, led to the recovery of two diploids and one triploid. The stability of the fusion yeasts was tested by plating them on non-selective medium after several growth cycles under antibiotics and then testing five colonies per strain for nuclear DNA contents using flow cytometry and standard cell cycle analysis: the triploid and one diploid were stable. Fusants inherited their mitochondria from a single parent, which was demonstrated using restriction fragment length polymorphism (RFLP) of mitochondrial DNA. The phenotypic properties of the parents and fusants were compared in glucose fed-batch bioreactor studies and cellulosic sugar batch cultures. The final lipid titers for the fed-batch cultures were 24.9-39.7 g/L with Y-6985 and the diploid and triploid performing the best and worst, respectively. The fusants demonstrated intermediate hardiness for growth on hydrolysate prepared with dilute-acid pretreated switchgrass and were outperformed by Y-48190. Unlike one of the haploid parents, the fusants grew in 70% v/v concentrated hydrolysate. However, they did not grow as fast as the other haploid. In this study, a modernized protoplast fusion method is resurrected a useful tool for strain development in this yeast, which is complementary with other available methods.

  PublisherOA PDFDOI

• Engineering of xylose metabolic pathways in <i>Rhodotorula toruloides</i> for sustainable biomanufacturing

  FEMS Yeast Research · 2025-01-01 · 4 citations

  reviewOpen access

  The oleaginous yeast Rhodotorula toruloides is a promising microbial cell factory for the sustainable production of biofuels and value-added chemicals from renewable carbon sources. Unlike the conventional yeast Saccharomyces cerevisiae, R. toruloides can naturally metabolize xylose, the second most abundant sugar in lignocellulosic hydrolysates. However, its native xylose metabolism is inefficient, characterized by slow xylose uptake and accumulation of D-arabitol. Moreover, despite its phenotype, research on the enzymes involved in xylose metabolism has yet to reach a consensus. Therefore, this review provides a comprehensive analysis of the non-canonical xylose metabolism in R. toruloides, focusing on the properties of key enzymes involved in xylose metabolism. Native xylose reductase and xylitol dehydrogenase exhibit broad substrate promiscuity compared to their counterparts in the xylose-fermenting Scheffersomyces stipitis. Additionally, the absence of xylulokinase expression under xylose-utilizing conditions redirects metabolism toward D-arabitol accumulation. Consequently, D-arabitol dehydrogenases and ribulokinase play essential roles in the xylose metabolism of R. toruloides. These findings highlight the fundamental differences between R. toruloides xylose metabolism and the oxidoreductase pathways observed in other xylose-fermenting yeast, providing insights for metabolic engineering strategies to improve xylose utilization and enhance bioconversion of cellulosic hydrolysates to different bioproducts by R. toruloides.

  PublisherOA PDFDOI

• A Unifying Equation for Fermentation Sustainability across the Titer-Rate-Yield Landscape

  ChemRxiv · 2025-11-17

  article

  Industrial fermentation underpins the global bioeconomy and is central to the sustainable production of fuels and chemicals. While commercial viability hinges on improvements in fermentation titer, rate, and yield (TRY), generalizable insight into how fermentation performance influences system cost remains elusive due to complex interactions among feedstocks, fermentation, separations, catalytic upgrading, waste management, and other decisions across diverse biomanufacturing facility designs. Here, we systematically mapped the entire theoretical fermentation performance spaces (formed by all potential combinations of TRY) for 32 representative biomanufacturing facilities—spanning distinct choices for feedstocks, fermentation regimes and products, separations, and catalytic upgrading—by simulating and evaluating them (by techno-economic analysis, TEA) under uncertainty (e.g., 600,000 Monte Carlo simulations) and across TRY combinations (e.g., 7,500 TRY combinations for 32 configurations). Strikingly, across this wide design and thermodynamic simulation space, the relationship between fermentation TRY and system cost could be captured with a simple, generalizable mathematical equation (R2 of 0.992−1.000 across our simulations; 0.954−1.000 when validated against prior studies that used different tools). We leveraged the proposed mathematical equation to elucidate key drivers—among biomanufacturing facility design decisions and uncertainties in technological and contextual parameters—that shape cost sensitivity to fermentation performance, generating widely applicable insights. By demonstrating that a unifying relationship governs the impact of fermentation on biomanufacturing economics, this work establishes a foundation for more agile, holistically predictive, and resource-efficient strategies to prioritize fermentation research and development needs and accelerate the commercialization of emerging fermentation technologies.

  PublisherDOI

• Selective designer hydrolysates preparation from the Miscanthus bioenergy crop for microbial lipid production: A way forward for sustainable biorefinery advancements

  SSRN Electronic Journal · 2025-01-01

  preprintOpen access
  PublisherDOI

Recent grants

• NIH Grant R01GM083601

  NIH · $1.4M · 2013

• CAREER: Quantitative analysis of translational regulation

  NSF · $400k · 2007–2013

Frequent coauthors

• Adam P. Arkin

  University of California, Berkeley

  37 shared

• Yong‐Su Jin

  University of Illinois Urbana-Champaign

  25 shared

• Sujit Sadashiv Jagtap

  University of Illinois Urbana-Champaign

  23 shared

• Hanna E. Walukiewicz

  University of Illinois Urbana-Champaign

  21 shared

• Phillip D. Aldridge

  Newcastle University

  17 shared

• George Ordal

  17 shared

• Anshu Deewan

  University of Illinois Urbana-Champaign

  14 shared

• David A. Parker

  12 shared

Education

• Ph.D., Bioengineering

  University of California, San Diego

  2000

• M.S., Bioengineering

  University of California, San Diego

  1996

• B.S., Bioengineering

  University of California, San Diego

  1994

Awards & honors

• Dean's Award for Excellence in Research, College of Engineer…
• Robert W. Schaefer Scholar, University of Illinois at Urbana…
• Helen Corley Petit Scholar, College of Liberal Arts and Scie…
• CAST Outstanding Young Researcher Award, American Institute…
• Inaugural High Impact Paper Award, International Federation…