Phylogenomic and biochemical analysis reassesses temperate marine yeast Yarrowia lipolytica NCIM 3590 to be Yarrowia bubula

Dynamics of the lipid body lipidome in the oleaginous yeast Yarrowia sp

Time-dependent changes in the lipid body (LB) lipidome of two oleaginous yeasts, Yarrowia lipolytica NCIM 3589 and Yarrowia bubula NCIM 3590 differing in growth temperature was investigated. LB size and lipid content were higher in Y. lipolytica based on microscopy, Feret, and integrated density analysis with lipid accumulation and mobilization occurring at 48 h in both strains. Variations in LB lipidome were reflected in interfacial tension (59.67 and 68.59 mN m-1) and phase transition temperatures (30°C-100°C and 60°C-100°C) for Y. lipolytica and Y. bubula, respectively. Liquid Chromatography-Mass Spectroscopy (LC-MS) analysis revealed neutral lipids (NLs), phospholipids, sphingolipids, sterols, and fatty acids as the major classes present in both strains while fatty acid amides were seen only in Y. lipolytica. Amongst the lipid classes, a few species were present in abundance with a number of lipids being less dominant. Permutational multivariate analysis of variance (PERMANOVA) and Analysis of covariance (ANOCOVA) analysis suggest 22 lipids belonging to NLs, fatty acid amides, and free fatty acids were found to be statistically different between the two strains. Analysis of the ratios between different lipid components suggest changes in LB size and mobilization as a function of time. The results indicate influence of temperature and strain variation on the dynamics of LB lipidome in Yarrowia species.

Sugar Alcohol Sweetener Production by Yarrowia lipolytica Grown in Media Containing Glycerol

Most of the world's annual production of mannitol is by chemical means, but, due to increasing demand for natural sweeteners, alternative production methods are being sought. The aim of the study was to screen Yarrowia lipolytica yeast strains and select culture conditions for the efficient and selective biosynthesis of mannitol from glycerol. From 21 strains examined in the shake-flask culture for mannitol biosynthesis from glycerol (100 g/L), three strains were selected-S2, S3, and S4-and further evaluated in batch bioreactor cultures with technical and raw glycerol (150 g/L). The best production parameters were observed for strain S3, which additionally was found to be the most resistant to NaCl concentration. Next, strain S3 was examined in batch culture with regard to the initial glycerol concentration (from 50 to 250 g/L). It was found that the substrate concentrations of 50 and 75 g/L resulted in the highest mannitol selectivity, about 70%. The fed-batch culture system proposed in this paper (performed in two variants in which glycerol was dosed in four portions of about 50 or 75 g/L) resulted in increased mannitol production, up to 78.5 g/L.

Assembly and comparative genome analysis of a Patagonian Aureobasidium pullulans isolate reveals unexpected intraspecific variation

Aureobasidium pullulans is a yeast-like fungus with remarkable phenotypic plasticity widely studied for its importance for the pharmaceutical and food industries. So far, genomic studies with strains from all over the world suggest they constitute a genetically unstructured population, with no association by habitat. However, the mechanisms by which this genome supports so many phenotypic permutations are still poorly understood. Recent works have shown the importance of sequencing yeast genomes from extreme environments to increase the repertoire of phenotypic diversity of unconventional yeasts. In this study, we present the genomic draft of A. pullulans strain from a Patagonian yeast diversity hotspot, re-evaluate its taxonomic classification based on taxogenomic approaches, and annotate its genome with high-depth transcriptomic data. Our analysis suggests this isolate could be considered a novel variant at an early stage of the speciation process. The discovery of divergent strains in a genomically homogeneous group, such as A. pullulans, can be valuable in understanding the evolution of the species. The identification and characterization of new variants will not only allow finding unique traits of biotechnological importance, but also optimize the choice of strains whose phenotypes will be characterized, providing new elements to explore questions about plasticity and adaptation.

A comprehensive assessment of Yarrowia lipolytica and its interactions with metals: Current updates and future prospective

The non-conventional yeast Yarrowia lipolytica has been popular as a model system for understanding biological processes such as dimorphism and lipid accumulation. The organism can efficiently utilize hydrophobic substrates (hydrocarbons and triglycerides) thereby rendering it relevant in bioremediation of oil polluted environments. The current review focuses on the interactions of this fungus with metal pollutants and its potential application in bioremediation of metal contaminated locales. This fungus is intrinsically equipped with a variety of physiological and biochemical features that enable it to tide over stress conditions induced by the presence of metals. Production of enzymes such as phosphatases, reductases and superoxide dismutases are worth a special mention. In the presence of metals, levels of inherently produced metal binding proteins (metallothioneins) and the pigment melanin are seen to be elevated. Morphological alterations with respect to biofilm formation and dimorphic transition from yeast to mycelial form are also induced by certain metals. The biomass of Y. lipolytica is inherently important as a biosorbent and cell surface modification, process optimization or whole cell immobilization techniques have aided in improving this capability. In the presence of metals such as mercury, cadmium, copper and uranium, the culture forms nanoparticulate deposits. In addition, on account of its intrinsic reductive ability, Y. lipolytica is being exploited for synthesizing nanoparticles of gold, silver, cadmium and selenium with applications as antimicrobial compounds, location agents for bioimaging and as feed supplements. This versatile organism thus has great potential in interacting with various metals and addressing problems related to their pollutant status.