Fatty acid distribution and polymorphism in solid lipid particles of milkfat and long chain omega-3 fatty acids

Saturated fatty acid-containing lipids, such as milkfat, may protect long chain polyunsaturated fatty acids in fish oil when blended together into solid lipid particles (SLPs). One of the main challenges of SLPs is structural polymorphism, which can lead to expulsion of the protected component during prolonged storage. To investigate this phenomenon, the change in thermal and crystalline behaviours, and fatty acid distribution, were analysed in SLPs of fish oil and milkfat during storage at different temperatures for up to 28 days. X-ray diffraction analysis showed changes in molten and crystalline states occurred even at –22 °C. Room temperature (21 °C) storage led to more than 45% molten state but SLPs retained their initial shape. Confocal Raman Spectroscopy of the SLPs showed the distribution of fatty acids was not uniform, with 10 μm outermost layer of predominantly saturated fatty acids likely responsible for the intact SLP shape and stability of the core

Metabolic engineering of yeast for enhanced natural and exotic fatty acid production

Lignocellulose-derived sugars and other biorefinery by-product streams such as glycerol and acetic acid are useful carbon feedstocks for microbes that produce lipids. Lipids have high energy density and are easily converted into versatile biofuels and valuable oleochemicals. Common, robust yeasts such as Saccharomyces cerevisiae and Yarrowia lipolytica have been the most successfully exploited as cell factories for lipid production, and excellent progress has been made in productivity with the implementation of synthetic biology tools and metabolic engineering strategies. Accumulation and storage of standard fatty acids as triacylglycerols or secretion of free fatty acids has been enhanced by modification of metabolic pathways yielding maximal fatty acid titers above 100 g L−1 and productivity of 0.8 g L−1 h−1. Production of higher-value exotic fatty acids that are not native to yeast, such as short chain, hydroxylated, and cyclopropane, has great potential but requires more research into lipid synthesis pathways and new metabolic engineering strategies to achieve similar productivities as achieved for standard fatty acids. In addition, monitoring of cell viability and health, balancing cofactor demands, and minimizing stress are important strategies to avoid or reduce metabolic burden caused by engineering of cells

Custom design of protein particles as multifunctional biomaterials

Assembled protein particles, as emerging biomaterials, have broad applications ranging from vaccines and drug delivery to biocatalysis and particle tracking, but to date these require trial-and-error rational design experimentation and/or intensive computational methods to generate. Here, the authors describe an easy-to-implement engineering strategy to generate customized protein particles as multifunctional biomaterials. They utilize protein–peptide modules to generate functional nanoparticles whose assembly and size is controlled by the addition of mild stimuli. The protein assembling method is versatile, as exemplified through particle formation with 7 distinct protein modules, using a variety of assembly conditions tailored by the chemistries of 3 peptide partners. They have generated customized protein particles using enzymes, binding and reporter proteins, and their functions and utilities are demonstrated using biocatalysis, sensing, and labelling applications, respectively. Furthermore, co-assembly with two functional proteins within one particle has been successfully achieved and demonstrated. Physical insights into the kinetics and molecular mechanisms of particle formation are revealed by small angle X-ray scattering and mass photometry, providing fundamental knowledge to guide design and manufacture these interesting biomaterials in future. Their protein assembling strategy is a reliable method for fabricating a protein particle to deliver new functionalities on-demand

Evolution of a new enzyme for carbon disulphide conversion by an acidothermophilic archaeon

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