More Like this

1. Enhancing Lipid Production in Yarrowia lipolytica Through Continuous Fermentation and Adaptive Laboratory Evolution in Bioreactors

   https://doi.org/10.1177/15509087251389709  

   Kurt, Elif; Qin, Jiansong; Sa, Lucas; Anjo, Evelyn; Xie, Dongming (January 2026, Industrial Biotechnology)

   Gross, Richard (Ed.)

   Yarrowia lipolyticaexcels in microbial lipid production, thriving across diverse conditions. Batch or fed-batch fermentation is the not only common practice to achieve higher lipid titer and yield but it is also subject to lower lipid productivity. Single-stage continuous fermentation (CF) provides a great potential for significantly higher productivity, but genetic instability is often seen and challenges strain performance over the long-period CF. This study harnesses single-stage CF to not only improve lipid productivity but also evolve high-lipid mutants from a previously engineeredY. lipolyticastrain E26 via adaptive laboratory evolution (ALE) in a continuous bioreactor, guided by a predictive kinetic model. The single-stage CF was run for 1128 hours (47 days) with key process parameters adjusted in a 1-L bioreactor to produce over 150 g/L yeast biomass, exceeding the targeted 113 g/L that is predicted by the model. Compared with the fed-batch fermentation process, the single-stage CF successfully improved lipid productivity from 0.3–0.5 g/L/h to about 1 g/L/h while maintaining the lipid yield at around 0.1 g/g. The CF sample at 1008 hours was used to isolate mutants with higher lipid production after ALE in the continuous bioreactor. A mutant E26E03 was identified, which demonstrated improvements in biomass, lipid content, and lipid yield by 43%, 30%, and 51%, respectively, over the original strain E26 in fed-batch fermentation. Our study indicated that using model-guided CF with ALE in a continuous bioreactor provides a great potential for significantly higher product titer, rate, and yield in biomanufacturing. 

   more » « less
2. Single‐Molecule 3D Orientation Imaging Reveals Nanoscale Compositional Heterogeneity in Lipid Membranes

   https://doi.org/10.1002/anie.202006207  

   Lu, Jin; Mazidi, Hesam; Ding, Tianben; Zhang, Oumeng; Lew, Matthew D. (August 2020, Angewandte Chemie International Edition)

   Abstract In soft matter, thermal energy causes molecules to continuously translate and rotate, even in crowded environments, thereby impacting the spatial organization and function of most molecular assemblies, such as lipid membranes. Directly measuring the orientation and spatial organization of large collections (>3000 molecules μm⁻²) of single molecules with nanoscale resolution remains elusive. In this paper, we utilize SMOLM, single‐molecule orientation localization microscopy, to directly measure the orientation spectra (3D orientation plus “wobble”) of lipophilic probes transiently bound to lipid membranes, revealing that Nile red's (NR) orientation spectra are extremely sensitive to membrane chemical composition. SMOLM images resolve nanodomains and enzyme‐induced compositional heterogeneity within membranes, where NR within liquid‐ordered vs. liquid‐disordered domains shows a ≈4° difference in polar angle and a ≈0.3π sr difference in wobble angle. As a new type of imaging spectroscopy, SMOLM exposes the organizational and functional dynamics of lipid‐lipid, lipid‐protein, and lipid‐dye interactions with single‐molecule, nanoscale resolution. 

   more » « less
3. Lipid metabolism in Calanus finmarchicus is sensitive to variations in predation risk and food availability

   https://doi.org/10.1038/s41598-020-79165-6  

   Skottene, Elise; Tarrant, Ann M.; Altin, Dag; Olsen, Rolf Erik; Choquet, Marvin; Kvile, Kristina Ø. (December 2020, Scientific Reports)

   Abstract Late developmental stages of the marine copepods in the genusCalanuscan spend extended periods in a dormant stage (diapause) that is preceded by the accumulation of large lipid stores. We assessed how lipid metabolism during development from the C4 stage to adult is altered in response to predation risk and varying food availability, to ultimately understand more of the metabolic processes during development inCalanuscopepods. We used RNA sequencing to assess if perceived predation risk in combination with varied food availability affects expression of genes associated with lipid metabolism and diapause preparation inC. finmarchicus. The lipid metabolism response to predation risk differed depending on food availability, time and life stage. Predation risk caused upregulation of lipid catabolism with high food, and downregulation with low food. Under low food conditions, predation risk disrupted lipid accumulation. The copepods showed no clear signs of diapause preparation, supporting earlier observations of the importance of multiple environmental cues in inducing diapause inC. finmarchicus. This study demonstrates that lipid metabolism is a sensitive endpoint for the interacting environmental effects of predation pressure and food availability. As diapause may be controlled by lipid accumulation, our findings may contribute towards understanding processes that can ultimately influence diapause timing. 

   more » « less
4. Phosphatidylserine affinity for and flip-flop dependence on Ca ²⁺ and Mg ²⁺ ions

   https://doi.org/10.1039/d4fd00206g  

   Hymas, Preston P; Conboy, John C (January 2025, Faraday Discussions)

   Ca²⁺ions are believed to play a crucial role in enzymatic regulation of lipid membrane asymmetry, yet direct effects of Ca²⁺on lipid flip-flop are unknown. Present work examines the influence of Ca–lipid interactions on lipid translocation. 

   more » « less
5. Lipid Landscapes: Vibrational Spectroscopy for Decoding Membrane Complexity

   https://doi.org/10.1146/annurev-physchem-090722-010230  

   Chen, Xiaobing; Al-Mualem, Ziareena A; Baiz, Carlos R (June 2024, Annual Review of Physical Chemistry)

   Cell membranes are incredibly complex environments containing hundreds of components. Despite substantial advances in the past decade, fundamental questions related to lipid-lipid interactions and heterogeneity persist. This review explores the complexity of lipid membranes, showcasing recent advances in vibrational spectroscopy to characterize the structure, dynamics, and interactions at the membrane interface. We include an overview of modern techniques such as surface-enhanced infrared spectroscopy as a steady-state technique with single-bilayer sensitivity, two-dimensional sum-frequency generation spectroscopy, and two-dimensional infrared spectroscopy to measure time-evolving structures and dynamics with femtosecond time resolution. Furthermore, we discuss the potential of multiscale molecular dynamics (MD) simulations, focusing on recently developed simulation algorithms, which have emerged as a powerful approach to interpret complex spectra. We highlight the ongoing challenges in studying heterogeneous environments in multicomponent membranes via current vibrational spectroscopic techniques and MD simulations. Overall, this review provides an up-to-date comprehensive overview of the powerful combination of vibrational spectroscopy and simulations, which has great potential to illuminate lipid-lipid, lipid-protein, and lipid-water interactions in the intricate conformational landscape of cell membranes. 

   more » « less