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Mead acid (MA; 20:3ω9) is one of the ω9 series of polyunsaturated fatty acids (PUFAs). MA is used to inhibit the inflammation of joints and is applied to the medicinal or health food field. We aimed to construct MA-producing strains with disruption of the Δ12-desaturase gene (Δ1 2ds) via an efficient gene-targeting system using the lig4 -disrupted strain of Mortierella alpina 1S-4 as the host. The transformants showed a unique fatty acid composition that only comprised ω9-PUFAs and saturated fatty acids, while ω6-and ω3-PUFAs were not detected, and the total composition of ω9-PUFAs, including oleic acid (18:1ω9), 18:2ω9, 20:1ω9, 20:2ω9, and MA, was up to 68.4% of the total fatty acids. The MA production in the Δ1 2ds -disruptant reached 0.10 g/L (8.5%), which exceeded 0.050 g/L (4.6%) in the conventional Δ1 2ds -defective mutant JT-180. [ABSTRACT FROM AUTHOR]

Aim: The effects of detergent, ethanol and ethanol with plant meadowfoam oil on the growth of the red heterobasidomycete Xanthophyllomyces dendrorhous and on the production of astaxanthin (3,3′‐dihydroxy‐β,β‐carotene‐4,4′‐dione) and fatty acids in this red yeast were investigated. Methods and Results: Ethanol supplementation at a final concentration of 0.8% (v/v) caused an increase in the growth, astaxanthin production and fatty acid production of treated X. dendrorhous compared with untreated X. dendrorhous. Supplementation of meadowfoam oil with 0.8% ethanol further improved the growth and astaxanthin production of X. dendrorhous. Fatty acid compositions following supplementation with various concentrations of ethanol and oil were also analysed. With 0.8% ethanol supplementation, the ratio of linoleic acid (C18:2) and α‐linolenic acid (C18:3ω3, ALA) decreased. Conversely, with 1.8% ethanol supplementation, the ALA ratio increased. Conclusions: Ethanol can serve as a promoting factor for coproduction of astaxanthin and fatty acids in X. dendrorhous, whereas simultaneous supplementation of ethanol and meadowfoam oil can cause further astaxanthin production. Significance and Impact of Study: Astaxanthin is widely used in various functional products because of its antioxidant activity. This study shows that X. dendrorhous can coproduce astaxanthin and functional fatty acids at high levels following supplementation with ethanol. [ABSTRACT FROM AUTHOR]

ω3 Polyunsaturated fatty acids are currently obtained mainly from fisheries; thus, sustainable alternative sources such as oleaginous microorganisms are required. Here, we describe the isolation, characterization, and application of 3 novel ω3 desaturases with ω3 polyunsaturated fatty acid–producing activity at ordinary temperatures (28 °C). First, we selected Pythium sulcatum and Plectospira myriandra after screening for oomycetes with high eicosapentaenoic acid/arachidonic acid ratios and isolated the genes psulω3 and pmd17 , respectively, which encode ω3 desaturases. Subsequent characterization showed that PSULω3 exhibited ω3 desaturase activity on both C18 and C20 ω6 polyunsaturated fatty acids while PMD17 exhibited ω3 desaturase activity exclusively on C20 ω6 polyunsaturated fatty acids. Expression of psulω3 and pmd17 in the arachidonic acid–producer Mortierella alpina resulted in transformants that produced eicosapentaenoic acid/total fatty acid values of 38% and 40%, respectively, at ordinary temperatures. These ω3 desaturases should facilitate the construction of sustainable ω3 polyunsaturated fatty acid sources. [ABSTRACT FROM AUTHOR]

C17 fatty acids, which are odd-chain fatty acids (OcFAs), have attractive commercial and medical value. Komagataella phaffii , a promising species of methylotrophic yeast, has received increasing attention due to its unique features. Especially, the insanely higher yield of C17 fatty acids in fermentation, compared with other methylotrophic yeast species, is expected to confirm K. phaffii as a promising biorefinery host for production of OcFAs. Moreover, co-supplementation of 0.1% propionate and 10 mM valine in a glucose-based medium, increased the productivity of C17 fatty acids in K. phaffii by 11.7-fold, and its production reached 4.36 mg/L. This research presents new insights into a non-genetically engineered method of OcFAs biosynthesis in K. phaffii. • Komogataella phaffii has the affirmative potential to be a biorefinery host for odd-chain fatty acids production. • For the production of odd-chain fatty acids in K. phaffii , glucose is the most suitable carbon source. • Supplementation of propionate and valine in the glucose medium is able to enhance the productivity of C17 fatty acids. [ABSTRACT FROM AUTHOR]

To develop an efficient gene-targeting system in Mortierella alpina 1S-4, we identified the ku80 gene encoding the Ku80 protein, which is involved in the nonhomologous end-joining pathway in genomic double-strand break (DSB) repair, and constructed ku80 gene-disrupted strains via single-crossover homologous recombination. The Δku80 strain from M. alpina 1S-4 showed no negative effects on vegetative growth, formation of spores, and fatty acid productivity, and exhibited high sensitivity to methyl methanesulfonate, which causes DSBs. Dihomo-γ-linolenic acid (DGLA)-producing strains were constructed by disruption of the Δ5- desaturase gene, encoding a key enzyme of bioconversion of DGLA to ARA, using the Δku80 strain as a host strain. The significant improvement of gene-targeting efficiency was not observed by disruption of the ku80 gene, but the construction of DGLA-producing strain by disruption of the Δ5- desaturase gene was succeeded using the Δku80 strain as a host strain. This report describes the first study on the identification and disruption of the ku80 gene in zygomycetes and construction of a DGLA-producing transformant using a gene-targeting system in M. alpina 1S-4. [ABSTRACT FROM AUTHOR]

Astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4′-dione) acts as a protective agent against oxidative damage to cells and is widely used in various industries. In this study, we profiled fatty acids in the astaxanthin-producing heterobasidomycete Xanthophyllomyces dendrorhous. Our analysis revealed that X. dendrorhous can produce α-linolenic acid (C18:3ω3) in its cells. To identify plant oils with positive effects on X. dendrorhous , we screened various oils and tested for coproduction of astaxanthin and fatty acids in the yeast. Interestingly, culturing X. dendrorhous with 0.01% (w/v) meadowfoam oil led to a three-fold increase in the growth of the yeast. Due to this increased growth, X. dendrorhous produced more total fatty acids (2.7-fold increase) and astaxanthin (1.4-fold increase) than were produced without oil supplementation. However, fatty acid composition did not change substantially under supplemented conditions. Thus, X. dendrorhous can coproduce industrially valuable astaxanthin and fatty acids, and meadowfoam oil can serve as a promoting factor for this coproduction. • Xanthophyllomyces dendrorhous is able to produce functional fatty acids including α-linolenic acid. • Meadowfoam oil substantially increases the growth of X. dendrorhous. • The increased growth led to improvement of astaxanthin and total fatty acid production in X. dendrorhous. [ABSTRACT FROM AUTHOR]

ω3-Docosapentaenoic acid (ω3-DPA), an ω3-polyunsaturated fatty acid (ω3-PUFA), is expected to have beneficial physiological functions to humans; however, because of its rarity in nature, it has not been fully analyzed. We isolated an ω3-DPA producing microorganism strain T7 from brackish areas in Japan. Although most oleaginous microorganisms rarely accumulate ω3-DPA (<5% of total lipid), strain T7 accumulated ω3-DPA with more than 20% of total fatty acids. The strain T7 was identified as a related species of Aurantiochytrium. In Aurantiochytrium sp. T7, ω3-DPA production reached 164 mg/L culture broth, and the ω3-DPA content reached 23.5% of the total fatty acids when cultivated in a medium containing 2% glucose as the carbon source and 1% yeast extract as the nitrogen source, with a salinity equivalent to 50% of that of seawater and a pH in the acidic range (pH < 5.5). Aurantiochytrium sp. T7 is a promising producer of high-purity ω3-DPA containing-lipid for the functional analysis of ω3-DPA whose physiological function has hardly been elucidated, and a useful strain for investigating the novel metabolic pathway of fatty acids. [ABSTRACT FROM AUTHOR]