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This paper represents a comprehensive study of two new thraustochytrids and a marine Rhodotorula red yeast isolated from Australian coastal waters for their abilities to be a potential renewable feedstock for the nutraceutical, food, fishery and bioenergy industries. Mixotrophic growth of these species was assessed in the presence of different carbon sources: glycerol, glucose, fructose, galactose, xylose, and sucrose, starch, cellulose, malt extract, and potato peels. Up to 14g DW/L (4.6gDW/L-day and 2.8gDW/L-day) of biomass were produced by Aurantiochytrium and Thraustochytrium species, respectively. Thraustochytrids biomass contained up to 33% DW of lipids, rich in omega-3 polyunsaturated docosahexaenoic acid (C22:6, 124mg/g DW); up to 10.2mg/gDW of squalene and up to 61μg/gDW of total carotenoids, composed of astaxanthin, canthaxanthin, echinenone, and β-carotene. Along with the accumulation of these added-value chemicals in biomass, thraustochytrid representatives showed the ability to secrete extracellular polysaccharide matrixes containing lipids and proteins. Rhodotorula sp lipids (26% DW) were enriched in palmitic acid (C16:0, 18mg/gDW) and oleic acid (C18:1, 41mg/gDW). Carotenoids (87μg/gDW) were mainly represented by β-carotene (up to 54μg/gDW). Efficient growth on organic and inorganic sources of carbon and nitrogen from natural and anthropogenic wastewater pollutants along with intracellular and extracellular production of valuable nutrients makes the production of valuable chemicals from isolated species economical and sustainable., (Crown Copyright © 2020. Published by Elsevier GmbH. All rights reserved.)

Bovine milk contains 3-5% of fat, of which the dominant portion (about 98%) is in the form of triacylglycerols, whereas polar lipids such as glycerophospholipids and sphingolipids are minor components (0.5-1%) of milk fat. Milk fat is thought to contain several thousand lipid species, making it the most complex material in nature in terms of lipid composition. Significant progress has been made in the past two decades in the identification and quantification of lipid species of milk thanks to the advance in analytical tools especially high-resolution mass spectrometers (MS). Currently, milk lipids are characterized mainly in two ways, i.e. global fatty acid composition profiling by gas chromatography and lipid molecular species identification and quantification by liquid chromatography tandem MS; the former provides information related to the physicochemical properties and nutritive quality of milk fat, whereas the latter provides the detailed chemical structure of lipid species. Until now, only about 400 lipid species have been described in bovine milk, with many low-abundance species remaining to be discovered. The merits and limitations of various separation techniques and different MS methodologies applied to lipid structural elucidation and quantification are critically reviewed and the challenging problems to be solved in milk lipidomic analysis highlighted., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The aquatic plant Azolla became increasingly popular as bioenergy feedstock because of its high growth rate, production of biomass with high levels of biofuel-producing molecules and ability to grow on marginal lands. In this study, we analysed the contribution of all organs of Azolla to the total yield of lipids at vegetative and reproductive stages and in response to stress. Triacylglycerol-containing lipid droplets were detected in all (vegetative and reproductive) organs with the highest level in the male microsporocarps and microspores. As a result, significantly higher total yields of lipids were detected in Azolla filiculoides and Azolla pinnata at the reproductive stage. Starving changed the yield and composition of the fatty acid as a result of re-direction of carbon flow from fatty acid to anthocyanin pathways. The composition of lipids, in regard the length and degree of unsaturation of fatty acids, in Azolla meets most of the important requirements for biodiesel standards. The ability of Azolla to grow on wastewaters, along with their high productivity rate, makes it an attractive feedstock for the production of biofuels., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

Seasonal change of milk composition could offer opportunities for dairy manufacturers. A systematic survey on seasonal variation of six classes of polar lipids was conducted with 19 Holstein cows over the entire milking season using liquid chromatography-mass spectrometry technique. This study revealed that most polar lipid classes were positively correlated with the total fat content, but negatively correlated with fat globule size. All polar lipid classes displayed a large cow-to-cow variation as well as seasonal variation. All of the six classes showed a gradual increase over the milking season with the highest concentration observed in May (autumn). However, the proportion of different polar lipid classes remained constant during the entire milking season. This finding suggests that the production of polar lipids is highly regulated in the mammary gland. The implication of such a seasonal variation of polar lipids in the nutritional and technological aspects of milk is discussed., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

For LC-MS-based lipidomic analysis of milk, total lipid extraction from raw milk is generally conducted with Folch or Bligh and Dyer methods; both methods are based on two-phase partition of lipids, and thus time-consuming. In this work, three solvent systems for one-phase extraction of milk lipids were compared with the standard Folch method. Two of the solvent systems (butanol/methanol, 3:1 and 1:1) previously tested for lipid extraction from plasma were found to provide adequate extraction for polar lipids, but incomplete extraction for triglycerides, especially highly lipophilic species. By contrast, our newly designed solvent mix composed of butanol, methanol and chloroform (at a 3:5:4 ratio) provided similar extraction efficiency for triglycerides and higher yield for some of the phospholipids, as compared to the Folch method. This new one-phase extraction method is very simple yet comprehensive and thus suitable for high throughput lipid analysis of milk samples., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Polar lipids (PLs) are a significant functional component of milk that are difficult to quantitate. A simple method for comprehensive identification and quantitative analysis of all essential PL species using bovine milk is described. The lipid fraction was extracted by a mix of chloroform and methanol and the extract was directly used for PL identification and quantification. PLs were separated by hydrophilic interaction liquid chromatography (HILIC) and detected by an Orbitrap mass analyser in positive mode. The structure of PLs was established or confirmed by tandem MS in both positive and negative modes. The method is sensitive (with a LOD for all PL classes ≤0.1 ng) and reproducible, enabling simultaneous quantification of 70 PL species within a run of 45 min. Application of this method to the quantification of PLs in 32 bovine milk samples revealed the relative abundance of different PL classes, significant variation of PL content between individual samples and the correlation between the major PL classes. The method provides a tool for investigating the variation and metabolism of important PL components in bovine and human milk and in diverse mammalian species., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Milk is a rich source of lipids, with the major components being triglycerides (TAG) and phospholipids (mainly phosphatidylcholine (PC), sphingomyelin (SM), phosphatidylethanolamine (PE), phosphatidylserine (PS) and phosphatidylinositol (PI)). Liquid chromatography-mass spectrometry (LC-MS) is the predominant technique for lipid identification and quantification across all biological samples. While fatty acid (FA) composition of the major lipid classes of milk can be readily determined using tandem MS, elucidating the regio-distribution and double bond position of the FA remains difficult. Various workflows have been reported on the quantification of lipid species in biological samples in the past 20 years, but no standard or consensus methods are currently available for the quantification of milk phospholipids. This study will examine the influence of several common factors in lipid analysis workflow (including lipid extraction protocols, LC stationary phases, mobile phase buffers, gradient elution programmes, mass analyser resolution and isotope correction) on the quantification outcome of bovine milk phospholipids. The pros and cons of the current LC-MS methods as well as the critical problems to be solved will also be discussed. [ABSTRACT FROM AUTHOR]

Abstract Determination of the fatty acid profile of milk fat generally involves a protocol that comprises total lipid extraction, transesterification and GC analysis. The lipid extraction step is time-consuming and often employs toxic solvents such as chloroform. A novel protocol is presented here that skips the lipid extraction step and allows the determination of fatty acid composition via direct methylation of milk fat isolated after centrifugation of raw milk. This new method is reliable for relative quantification of fatty acids in raw milk fat and offers a much higher throughput compared with the classical methods. [ABSTRACT FROM AUTHOR]