Engineering Yeast for Better Production of Natural Red Pigment

Greg Howard
12th June, 2024

Engineering Yeast for Better Production of Natural Red Pigment

Image Source: Natural Science News, 2024

Key Findings

  • Researchers at Tianjin University developed a method to produce betanin, a natural red-violet pigment, using engineered yeast cells
  • By enhancing enzyme activity and optimizing metabolic pathways, they achieved a seven-fold increase in betanin production
  • The engineered yeast strain BEW10 produced the highest reported titer of betanin in a shake flask setting, demonstrating a sustainable and efficient production method
The use of natural food colorants has been gaining traction due to consumer demand for healthier and more environmentally friendly alternatives to synthetic dyes. Betanin, a red-violet pigment from the betacyanin family, is one such natural colorant that has attracted significant interest for its application in the food industry and its health benefits. However, the commercial production of betanin, typically extracted from red beetroot, faces economic and sustainability challenges. Researchers at Tianjin University have conducted a study to address these issues by exploring microbial heterologous production of betanin in Saccharomyces cerevisiae, a type of yeast[1]. Betanin's appeal lies in its vibrant color and potential health benefits, which include antioxidant properties. However, its extraction from natural sources like beetroot is not only costly but also limited by agricultural factors and environmental sustainability. To overcome these hurdles, the study focused on the de novo production of betanin using engineered yeast cells. The researchers employed combinatorial engineering of plant P450 enzymes and precursor metabolisms to enhance betanin production. P450 enzymes are a group of enzymes involved in the synthesis of various molecules, including pigments. By using computer simulation and molecular docking, the team improved the catalytic activity of the enzyme CYP76AD, which is crucial in the betanin biosynthesis pathway. They performed alanine substitution and site-directed saturation mutagenesis to identify a combination mutant that showed a seven-fold increase in betanin production compared to the wild type. Enhancing the metabolic pathways for l-tyrosine and UDP-glucose, both of which are precursors in betanin biosynthesis, further improved production levels. These modifications were critical because l-tyrosine is a starting material for betanin synthesis, and UDP-glucose is necessary for glycosylation, a chemical process that stabilizes the pigment. After optimizing the fermentation process, the engineered yeast strain BEW10 achieved a betanin production level of 134.1 mg/L from sucrose, marking the highest reported titer of betanin produced by microbes in a shake flask setting. This significant improvement demonstrates the potential of metabolic engineering and enzyme optimization in producing complex natural products efficiently and sustainably. This study builds on previous research into natural pigments and their applications. For example, betalains, including betanin, have been recognized for their potential in food, pharmaceuticals, and cosmetics due to their vibrant colors and health-promoting properties[2]. However, the stability and scalability of natural pigments have been challenging[3]. By using microbial production methods, the current study addresses these limitations, offering a more stable and scalable solution. Moreover, the study's findings align with earlier research on the health impacts of artificial food colorants. A randomized trial found that artificial food colorants and additives could increase hyperactivity in children[4]. This has driven the demand for natural alternatives, further highlighting the importance of developing efficient and sustainable methods for producing natural pigments like betanin. In summary, the study conducted by Tianjin University showcases an innovative approach to producing betanin using engineered yeast cells. By enhancing enzyme activity and optimizing metabolic pathways, the researchers achieved a significant increase in betanin production. This advancement not only addresses the economic and sustainability challenges of traditional extraction methods but also supports the growing demand for natural food colorants. The study represents a meaningful step forward in the field of metabolic engineering and the commercial production of natural pigments.

BiotechGeneticsBiochem

References

Main Study

1) Enzyme and Pathway Engineering for Improved Betanin Production in Saccharomyces cerevisiae.

Published 11th June, 2024

https://doi.org/10.1021/acssynbio.4c00195

Related Studies

2) Multi-colored shades of betalains: recent advances in betacyanin chemistry.

https://doi.org/10.1039/d1np00018g

3) Natural Colorants: Food Colorants from Natural Sources.

https://doi.org/10.1146/annurev-food-030216-025923

4) Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial.

Journal: Lancet (London, England), Issue: Vol 370, Issue 9598, Nov 2007


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