Diacronema lutheri strain:NIVA-4/92 Genome sequencing and assembly

Whole nuclear genome assembly of Pavlova lutheri (Diacronema lutheri) strain NIVA-4/92. The main objective was to assemble a high-quality genome for the Pavlovales, which is significant for haptophyte evolution and the production of lipids in biotechnology

The Genome of the Haptophyte Diacronema lutheri (Pavlova lutheri, Pavlovales) : A Model for Lipid Biosynthesis in Eukaryotic Algae

Haptophytes are biogeochemically and industrially important protists with underexplored genomic diversity. We present a nuclear genome assembly for the class Pavlovales, which was assembled with PacBio long-read data into highly contiguous sequences. We sequenced strain Diacronema lutheri NIVA-4/92, formerly known as Pavlova lutheri, because it has established roles in aquaculture and has been a key organism for studying microalgal lipid biosynthesis. Our data show that D. lutheri has the smallest and most streamlined haptophycean genome assembled to date, with an assembly size of 43.503 Mb and 14,446 protein-coding genes. Together with its high nuclear GC content, Diacronema is an important genus for investigating selective pressures on haptophyte genome evolution, contrasting with the much larger and more repetitive genome of the coccolithophore Emiliania huxleyi. The D. lutheri genome will be a valuable resource for resolving the genetic basis of algal lipid biosynthesis and metabolic remodeling that takes place during adaptation and stress response in natural and engineered environments

Growth and LC-PUFA production of the cold-adapted microalga Koliella antarctica in photobioreactors

Microalgae are excellent sources of polyunsaturated fatty acids (PUFAs), but only a few species have been thoroughly investigated in controlled photobioreactor conditions. In this work, the cold-adapted microalga Koliella antarctica (Trebouxiophyceae) was cultivated at 15 °C to optimize growth and PUFA production in bubble-tube and flat-plate photobioreactors. The impact of nitrogen starvation, phosphorus starvation, salinity, and light intensity on the growth, fatty acid, and protein content was investigated. After culture optimization, a maximum biomass productivity of 2.37 g L−1 day−1 and maximum cell density of 11.68 g L−1 were achieved. Among all conditions tested, the maximum total fatty acid (TFA) content measured 271.9 mg g−1 dry weight in the late stationary phase. Nitrogen and phosphorus starvation strongly induced neutral lipid (TAG) accumulation, up to 90.3% of TFA, which mostly consisted of the monounsaturated fatty acid C18:1n−9 (oleic acid, OA). PUFAs were also abundant and together accounted for 30.3–45.8% of total triacylglycerol (TAG). The highest eicosapentaenoic acid (EPA) content (C20:5n−3) amounted to 6.7 mg g−1 dry weight (4.9% TFA) in control treatments, while the highest arachidonic acid (ARA) content (C20:4n−6) was 9.6 mg g−1 dry weight (3.5% TFA) in the late stationary phase. Phosphorus starvation was an effective strategy to obtain high total fatty acid yields (mg L−1) while maintaining the protein, total PUFA, and omega-3 fatty acid contents.</p

Correction to: Growth and LC-PUFA production of the cold-adapted microalga Koliella antarctica in photobioreactors

The article “Growth and LC-PUFA production of the cold‐adapted microalga Koliella antarcticain photobioreactors”, written by Hirono Suzuki, Chris J. Hulatt, René H. Wijffels, and Viswanath Kiron was originally published electronically on the publisher’s internet portal (currently SpringerLink) on August 25, 2018 without open access.With the author(s)’ decision to opt for Open Choice the copyright of the article changed on October 17, 2018 to © The Author(s) 2018 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits use, duplication, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license and indicate if changes were made

Corrigendum to “Polar snow algae as a valuable source of lipids?” [Bioresour. Technol. 235 (2017) 338–347](S096085241730411X)(10.1016/j.biortech.2017.03.130)

The authors regret that in the original version of this article, the culture collection strain ID numbers of the microalgae given in materials and methods Table 1 were not correctly assigned to the species names. The following revised Table 1 provides the correct strain ID numbers and information. The authors take the opportunity to note that the taxonomy of some of these strains is still under review (see “cf.” in Table 1). Recently, discussions have arisen regarding the correct taxonomy of CCCryo 194-04 (pers. comm. T. Leya, curator of CCCryo). Kawasaki et al. (2015) have recently revised several coccalean, oil-producing green algae and have assigned CCCryo 340b-08 (which is the same species as CCCryo 194-04) to the genus Macrochloris. On the other hand, it is currently being evaluated whether CCCryo 194-04 should be assigned to a different, still to be erected and published species within the genus Pleurastrum. The true taxonomy (and names) of some strains thus remain unclear at this time, and so the strain ID numbers containing the collection acronym listed above should be used to identify the microalgae used in this work. The authors would like to apologise for any inconvenience caused.</p

Fatty acids in the neutral lipids (TAG) of <i>Nannochloropsis</i>.

<p>(a) Individual fatty acids (b) Total fatty acids. Data are mg∙g^-1 dry cell weight after 8, 12 and 16 days of cultivation in low-NP medium. Data is the mean of three replicate cultivations and error bars indicate the standard deviation.</p

Cell protein content <i>vs</i> EPA, calorific value and total fatty acids.

<p>(a) The relationship between the percentage of protein and the percentage EPA in dry cell mass after 8, 12 and 16 days of cultivation in low-NP and high-NP treatments is described by a linear fit. (b) The relationship between the percentage of protein and the calorific value after 8, 12 and 16 days of cultivation in low-NP and high-NP treatments is described by a linear fit. (c) The relationship between the percentage protein and total fatty acids across all treatments is described by a quadratic fit (for visual guidance) where <i>y</i> = 0.024∙<i>x</i>²–2.52∙<i>x</i> + 75.9. Each data point is derived from a single cultivation (<i>n</i> = 18).</p

Percentage fatty acid composition (% total fatty acids) of <i>Nannochloropsis</i> neutral lipids (TAG) at three different growth phases in low-NP medium.

<p>Percentage fatty acid composition (% total fatty acids) of <i>Nannochloropsis</i> neutral lipids (TAG) at three different growth phases in low-NP medium.</p