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Updated: May 13, 2025
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Genetic Engineering of an Unconventional Yeast for Renewable Biofuel and Biochemical Production
Published on: September 20, 2016
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Unsilencing a cryptic xylose metabolic pathway in Rhodococcus jostii RHA1 for efficient lipid production from
Miguel G Acedos1,2, Isabel De la Torre3, Jorge Barriuso3
1Department of Biotechnology, Centro de Investigaciones Biológicas Margarita Salas, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain. miguel.garciaacedos@ciemat.es.
Journal of Biological Engineering
|April 14, 2025
Summary
Adaptive laboratory evolution (ALE) enabled Rhodococcus jostii RHA1 to efficiently metabolize xylose for biofuel production. This strain co-utilizes glucose and xylose, overcoming limitations of previous engineered microbes.
Area of Science:
- Microbial biotechnology
- Synthetic biology
- Metabolic engineering
Background:
- Rhodococcus jostii RHA1 is an oleaginous bacterium with potential for biofuel production.
- The wild type strain cannot metabolize xylose, limiting its use with lignocellulosic biomass.
- Genetic engineering approaches have been used to enable xylose metabolism.
Purpose of the Study:
- To evolve Rhodococcus jostii RHA1 to metabolize xylose without genetic engineering.
- To develop a strain capable of co-utilizing glucose and xylose for enhanced lipid accumulation.
- To investigate the metabolic pathways involved in xylose utilization in the evolved strain.
Main Methods:
- Adaptive laboratory evolution (ALE) was employed to select for xylose-utilizing R. jostii RHA1.
- Comparative analysis with a recombinant strain engineered with heterologous xylose metabolic genes.
- Transcriptomic analysis to identify upregulated metabolic pathways.
- Enzyme activity assays and metabolite analysis to confirm the xylose metabolic route.
Main Results:
- An ALE-evolved strain (ALE-xyl) efficiently utilizes xylose as a sole carbon source.
- The ALE-xyl strain outperforms a previously engineered strain in xylose metabolism.
- ALE-xyl demonstrates simultaneous consumption of glucose and xylose, leading to efficient lipid accumulation.
- Transcriptomics revealed overexpression of a silent pentose metabolizing operon in the presence of xylose.
- Evidence suggests xylose is metabolized via a reductase pathway, indicated by detected xylose reductase activity and xylitol presence.
Conclusions:
- Adaptive laboratory evolution is a powerful tool for improving microbial strains for industrial applications without genetic engineering.
- ALE can unlock the silent metabolic potential of microorganisms for efficient bioprocessing.
- The developed ALE-xyl strain offers a promising platform for biofuel production from lignocellulosic biomass by co-utilizing sugars.
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