Sterilized tobacco leaves as biomass source for a biorefinery: CAS QIBEBT

http://english.cas.cn/newsroom/research-news/202604/t20260428_1158214.shtml

https://www.pnas.org/doi/10.1073/pnas.2530496123

Researchers from the CAS Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) have identified a conserved ubiquitin-mediated regulatory mechanism that coordinates metabolic flux among multiple biosynthetic pathways in yeast.

Eukaryotic cells operate under constant resource constraints, requiring them to allocate limited carbon supplies among multiple biosynthetic processes. Pathways responsible for producing carotenoids, sterols, and lipids are particularly interconnected, as they rely on shared metabolic precursors. Yet how cells dynamically balance these competing demands has remained unclear.

Using astaxanthin-producing Xanthophyllomyces dendrorhous yeast, the researchers identified an E3 ubiquitin ligase, PTR1, as a central regulatory hub that links carotenoid, sterol, and lipid metabolism. Further analysis revealed a PTR1-centered regulatory network that integrates these pathways. PTR1 modulates carotenoid biosynthesis through a reciprocal regulatory loop with the White Collar Complex (WCC), which is a key transcriptional regulator associated with carotenoid production. In addition, several PTR1-interacting proteins were identified, suggesting broader roles in fine-tuning sterol and lipid metabolism. Importantly, PTR1 homologs are conserved across diverse eukaryotic lineages, indicating that ubiquitin-mediated regulation represents an evolutionarily conserved strategy for coordinating metabolic networks.

http://english.cas.cn/newsroom/research-news/202604/t20260423_1157877.shtml

https://doi.org/10.1016/j.tibtech.2026.03.017

A team led by the CAS Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) has developed a new “process ramanomics” platform. This technology enables real-time, data-driven control of biomanufacturing.

The researchers validated their approach in polyhydroxyalkanoate (PHA) fermentation, a key route for biodegradable polyesters used in packaging and medical materials. Powered by machine learning, the platform achieved 99.75% accuracy in distinguishing PHB-producing cells from P34HB-producing ones, and quantified total PHA content and monomer composition at the single-cell level with a median absolute deviation below 3.8%, comparable to traditional gas chromatography.

In a pivotal 5,000-liter industrial fermenter trial, traditional offline testing pointed to harvesting at 28 hours when PHA content registered 66.32%. Process ramanomics, however, revealed a compositional shift invisible to conventional methods: the 4HB monomer ratio was 8.67% at 26 hours (within specification) but climbed to 11.28% by 28 hours, exceeding the compliance limit, demonstrating that earlier termination could safeguard product quality.

The platform’s single-cell resolution also showed that the content of intracellular PHA can vary by more than threefold among individual cells. At 26 hours, population heterogeneity was lowest, with 91.54% of cells producing at high levels and a 4HB composition that was within specification. This confirmed that 26 hours was the optimal harvest window.

The scientists further showed that process ramanomics can be applied to different chassis organisms and products. For example, it can be used for protein synthesis in yeast and lipid synthesis in Rhodococcus. This suggests that process ramanomics could serve as a general-purpose analytics engine for next-generation intelligent bioreactors.