Lipid classes and fatty acid composition of rotifers (Brachionus plicatilis) fed two algal diets

Rotifers (Brachionus plicatilis), maintained on baker's yeast, were fed for 24h upon two algal diets, Isochrysis galbana (diet A) and Isochrysis galbana + Nannochloropsis gaditana (diet B). (These algal diets were selected for their potential use as essential fatty acid (EFA) boosters, taking into account the requirements of fish larvae). The effect of these algal diets on total lipid content, lipid classes and fatty acid composition was studied. The total lipid content increased after feeding upon both diets but no significant differences were found between the two types. Neutral lipid and polar lipid contents increased and a positive correlation was observed between the neutral lipids content of rotifers and that of the food supplied. However, the content of polar lipids in rotifers did not depend upon that of the diet. The increase in neutral lipid content was found to be higher in rotifers fed upon diet B, compared to diet A which increased the phospholipid content. Non-enriched rotifers contained only small amounts of polyenoic fatty acids, i.e. 18:3n-6, 18:3n-3, 20:4n-6, 20:5n-3 and 22:6n-3, the contents of which increased significantly by feeding both diets. The EFA composition (20:4n-6, 20:5n-3 and 22:6n-3) of neutral lipids and phopholipids in rotifers reflected the EFA composition of each diet. Diet B-fed rotifers had the highest content in 20:4n-6 and 20:5n-3, whereas rotifers fed diet A and the highest 22:6n-3 content. The mixed diet I. galbana + N. gaditana enhanced substantially the composition of lipid classes i.e. neutral lipids and of n-3 PUFA of rotifers in comparison with Isochrysis or yeast diets.     

Lipids of the Green Alga BotryococcusCultured in a Batch Mode

The lipid fraction of the green alga Botryococcuscultured in a batch mode was found to contain polar lipids (more than 50% of the total lipids), di- and triacylglycerols, sterols and their esters, free fatty acids, and hydrocarbons. In aging culture, the content of polar lipids somewhat decreased and that of triacylglycerols increased by more than four times. The content of hydrocarbons in the algal biomass did not exceed 0.9% and depended little on the culture age. Intracellular lipids contained saturated and unsaturated (mono-, di-, and trienoic) fatty acids. The maximum content of C_{16 : 3}and -C_{18 : 3}fatty acids (up to 35% of the total fatty acids) was detected in the phase of active growth. The extracellular and intracellular lipids of the alga differed in the proportion of particular lipids and in the fatty acid pattern.     

Fatty acid,menaquinone and polar lipid composition of Rothia dentocariosa

The lipid compositions of Rothia dentocariosa was investigated. All of the strains tested possessed closely related lipid profiles consisting of predominantly straight-chain saturated and methyl branched long-chain fatty acids, unsaturated menaquinones with seven isoprene units and a polar lipid composition comprising diphosphatidylglycerol, phosphatidylglycerol and a diglycosyldiacylglycerol. The results of the present study indicate Rothia dentocariosa is a good and distinct taxon. The lipid data however does not support the classification of Rothia dentocariosa in the family Actinomycetaceae.     

Cold hardening induces transfer of fatty acids between polar and nonpolar lipid pools in the Arctic collembollan Megaphorura arctica

Cold hardiness in the Arctic Collembola Megaphorura arctica (Tullberg), formerly Onychiurus arcticus, has been the subject of extensive studies over the last decade. This species employs an unusual strategy known as cryoprotective dehydration to survive winter temperatures as low as ?25 °C. To expand knowledge of cryoprotective dehydration in M. arctica, the present study investigates how a reduction in ambient temperature affects the fatty acid composition of the total body lipid content along with polar (mainly membrane phospholipids) and nonpolar (mainly triacylglycerols) lipids. Most ectothermic animals compensate for changes in fluidity by regulating fatty acid composition, a process often described as homeoviscous adaptation. In M. arctica, changes in the fatty acid composition of total body lipid content during cold treatment are only moderate, with no clear pattern emerging. However, the levels of unsaturated fatty acids in the polar lipids increase with cold exposure, largely attributable to 16 : 1(n? 7), 18 : 1(n? 9), 18 : 3(n? 6) and 18 : 3(n? 3), whereas unsaturated fatty acid levels in the nonpolar lipids correspondingly decrease. These results suggest a reallocation of fatty acids between the two lipid pools as a response to a temperature reduction of 6 °C. Because of hypometabolism, a characteristic of cold adaptation, such a mechanism could be less energy demanding than de novo synthesis of fatty acids and may comprise part of an adaptive homeostatic response.     

Isolation and characterization of a novel mesophilic,fresh-water methanogen from river sediment Methanoculleus oldenburgensis sp. nov.

A new mesophilic, irregular coccoid methanogen isolated from a river sediment is described. Hydrogen plus carbon dioxide or formate served as substrates for methanogenesis in a mineral salt medium. For growth acetate is strictly required. Elevated levels of sodium chloride were not required and were inhibitory at concentrations above 1.5% (w/v). The optimal growth temperature was at 45°C. The DNA base ratio was 48.6±1 mol% G+C. The polar lipid pattern and the polyamine content were similar to that found in several Methanoculleus species. The new isolate CB-1 was assigned as Methanoculleus oldenburgensis (DSM 6216).     

Lipid composition of the entomopathogenic fungus Nomuraea rileyi

The total lipid content, neutral and polar lipid composition, and fatty acid profiles were determined for the different developmental stages of the entomopathogenic fungus, Nomuraea rileyi. In general, the lipid composition of N. rileyi was found to be very similar to that of other Fungi Imperfecti. Triacylglycerides and sterols were the major neutral lipids and phosphatidylethanolamine, phosphatidylinositol, and phosphatidylserine were the major polar lipids. Phosphatidylcholine, resolved in conidial and mycelial samples, was not detected in hyphal body samples. The major fatty acids were palmitic, oleic, and linoleic. Stearic acid was detected as a minor component of hyphal body samples. During conidiogenesis the overall lipid composition was altered in (1) a reduction in total lipid content, (2) an increase in the polar/neutral lipid ratio, and (3) an increase in the degree of fatty acid unsaturation.     

Effects of salinity on cell growth and docosahexaenoic acid content of the heterotrophic marine microalga Crypthecodinium cohnii

The effects of salinity on cell growth and docosahexaenoic acid (DHA) content of three marine microalgal strains, Crythecodinium cohnii ATCC 30556, C. cohnii ATCC 50051 and C. cohnii RJH were investigated. The lag phases of the three strains increased with increasing salinity in Porphyridium medium. The specific growth rate of C. cohnii ATCC 30556 was the highest at 9 g L⁻¹ NaCl while the other two strains had their highest specific growth rates at 5 g L⁻¹ NaCl. The highest cell dry weight concentrations of 2.51 g L⁻¹ and 1.56 g L⁻¹ were achieved at 9 g L⁻¹ NaCl for C. cohnii ATCC 30556 and ATCC 50051, respectively, while the highest dry weight concentration of 2.49 g L⁻¹ was achieved at 5 g L⁻¹ NaCl for C. cohnii RJH. The highest cell growth yield coefficient on glucose was 0.5 g g⁻¹ for both C. cohnii ATCC 30556 and C. cohnii RJH and 0.45 g g⁻¹ for C. cohnii ATCC 50051. All three strains responded to the change of salinity by modifying their cellular fatty acid compositions. At 9 g L⁻¹ NaCl, C. cohnii ATCC 30556 had the highest total fatty acid content and DHA (C22:6) proportion. In contrast, C. cohnii ATCC 50051 and C. cohnii RJH had the highest DHA content at 5 g L⁻¹ NaCl. C. cohnii ATCC 30556 and ATCC 50051 had the highest DHA yield (131.55 and 68.24 mg L⁻¹ respectively) at 9 g L⁻¹ NaCl while C. cohnii RJH had the highest DHA yield (128.83 mg L⁻¹) at 5 g L⁻¹ NaCl. Received 27 May 1999/ Accepted in revised form 27 August 1999     

The scheduling of spawning with the moult cycle in Northern krill (Crustacea: Euphausiacea): a strategy for allocating lipids to reproduction

Summary

Euphausiids moult and grow throughout their life, which implies sharing of resources between growth and reproduction for adult krill. In the Northern krill, Meganyctiphanes norvegica (M. Sars), female krill produce eggs cyclically. Spawning moult cycles alternate with vitellogenic moult cycles for lipid yolk accumulation. Histology shows that lipids are associated with the R cells of the digestive gland in both sexes, with the yolk platelets of mature oocytes and with the fat body cell membranes and blood lacunae in reproducing females. Mature female krill can have a total lipid content twice as high as males, mostly due to accumulation in the ovary, the fat body and the haemolymph. In contrast, in males, as well as in non-reproducing females, the highest percentage of lipids is found in the digestive gland and the haemolymph. In Meganyctiphanes norvegica, the most abundant lipid fractions are polar lipids and triglycerides, the latter being relatively low in reproducing female gonad and fat body. Triglycerides are believed to be a pure energy source and polar lipids are essential for membrane development in embryos. The fatty acid content and composition of the triglyceride and polar lipid fractions in females are different from males, related to both reproductive and dietary processes. Higher levels of polyunsaturated fatty acids (PUFA) in the polar lipid fraction were found in reproductive females. During the non-reproductive season, the converse was found, indicating the specific role PUFA and other fatty acids play in growth and egg production. Adaptive processes linked to reproduction were studied comparatively in three populations of the Northern krill—Clyde Sea (W, Scotland), Kattegat (E, Denmark), Ligurian Sea (Mediterranean)—all differing considerably in climatic and trophic conditions. Such adjustments in lipid synthesis and storage are viewed as reproductive strategies developed by the Northern krill in response to different environmental conditions.     

Nature of the effect of ther locus on the lipid content of embryos of peas (Pisum sativum L.)

The aim of this work was to discover why pea (Pisum sativum L.) embryos recessive at the r locus (rr) have a higher lipid content than embryos dominant at this locus (RR). The r locus is a gene encoding starch-branching enzyme, rr embryos have a much lower activity of this enzyme than RR embryos, and hence a reduced rate of starch synthesis. The higher lipid content of rr embryos must be a consequence of this. We suggest that neither differences in the availability of substrate for lipid synthesis as a consequence of different rates of starch synthesis, nor differences in the capacity of the pathway for malonyl-CoA synthesis, account for the different lipid contents of RR and rr embryos. Lipid contents of the two sorts of embryo first diverge at a much later stage in development than divergence in starch content. Amounts of pyruvate and acetate, and activities of enzymes that convert triose phosphate to malonyl CoA are the same in the two sorts of embryo. Most of the lipid in developing embryos is polar, structural lipid, and polar lipid accounts for a large proportion of the difference in lipid content between the two sorts of embryo. This difference in structural-lipid content reflects considerable structural differences between the two sorts of embryo and is presumably the consequence of differences in rates of lipid turnover.Abbreviations DW dry weight - FW fresh weight - FAME fatty-acid methyl esters This work was supported by a grant-in-aid from the Agricultural and Food Research Council to the John Innes Institute. We are very grateful to Alan Jones for his valuable advice on lipid analysis and to Dr. Kay Denyer (Advanced Technologies, Cambridge, UK) for valuable discussions. We thank Dr. Cliff Hedley for the gift of the seed of the peas used in this work.     

Supercritical fluid extraction of lipids from the heterotrophic microalga Crypthecodinium cohnii

Microalgae biomass can be a feasible source of ω‐3 fatty acids due to its stable and reliable composition. In the present study, the Crypthecodinium cohnii growth and docosahexaenoic acid (DHA, 22:6ω3) production in a 100 L glucose‐fed batch fermentation was evaluated. The lipid compounds were extracted by supercritical carbon dioxide (SC‐CO₂) from C. cohnii CCMP 316 biomas, was and their fatty acid composition was analysed. Supercritical fluid extraction runs were performed at temperatures of 313 and 323 K and pressures of 20.0, 25.0 and 30.0 MPa. The optimum extraction conditions were found to be 30.0 MPa and 323 K. Under those conditions, almost 50% of the total oil contained in the raw material was extracted after 3 h and the DHA composition attained 72% w/w of total fatty acids. The high DHA percentage of total fatty acids obtained by SC‐CO₂ suggested that this extraction method may be suitable for the production of C. cohnii value added products directed towards pharmaceutical purposes. Furthermore, the fatty acid composition of the remaining lipid fraction from the residual biomass with lower content in polyunsaturated fatty acids could be adequate for further uses as feedstock for biodiesel, contributing to the economy of the overall process suggesting an integrated biorefinery approach.     

The effect of cadmium on lipid and fatty acid biosynthesis in tomato leaves

This research aims to examine the effect of cadmium uptake on lipid composition and fatty acid biosynthesis, in young leaves of tomato treated seedlings (Lycopersicon esculentum cv. Ibiza F1). Results in membrane lipids investigations revealed that high cadmium concentrations affect the main lipid classes, leading to strong changes in their composition and fatty acid content. Thus, the exposure of tomato plants to cadmium caused a concentration-related decrease in the unsaturated fatty acid content, resulting in a lower degree of fatty acid unsaturation. The level of lipid peroxides was significantly enhanced at high Cd concentrations. Studies of the lipid metabolism using radioactive labelling with [1-¹⁴C]acetate as a major precursor of lipid biosynthesis, showed that levels of radioactivity incorporation in total lipids as well as in all lipid classes were lowered by Cd doses. In total lipid fatty acids, [1-¹⁴C]acetate incorporation was reduced in tri-unsaturated fatty acids (C16:3 and C18:3); While it was enhanced in the palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0) and linoleic (C18:2) acids. [1-¹⁴C]acetate incorporation into C16:3 and C18:3 of galactolipids [monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG)] and some phospholipids [phosphatidylcholine (PC) and phosphatidylglycerol (PG)] was inhibited by Cd stress. Our results showed that in tomato plants, cadmium stress provoked an inhibition of polar lipid biosynthesis and reduced fatty acid desaturation process.     

Effects of CO2 and nitrogen supply on the biochemical composition of Ulva rigida with especial emphasis on lipid class analysis

Lipid class composition was analysed in the green macroalga Ulva rigida grown under normal (350 ppm) and high (10,000 ppm) CO₂ levels, and in nitrate saturated and nitrogen limited conditions. A new protocol for the extraction of lipids has been defined. Culture conditions altered the fate of assimilated carbon, and significant changes were observed in protein and total lipid content in particular. A CO₂-enriched atmosphere conditioned the effects of nitrogen limitation on lipid class composition, revealing deep qualitative changes in carbon metabolism. Triglycerides accumulated at high CO₂ and under nitrogen limitation, while chloroplast-related lipids showed an inverse response. Changes in phospholipids could be related to carbon availability as they did not respond to nitrogen limitation. The ratio sterols/acetone-mobile polar lipids followed a negative linear relation with the optimum quantum yield for photosynthetic electron transport (F_v/F_m), and was considered as an index of the «light status» of the cell. The specificity of the response of lipid classes to growth conditions in U. rigida emphasizes the potential role of lipid class analyses as a diagnostic tool for environmental stress.     

Fatty-acid composition of polar lipids in fruit and leaf chloroplasts of “16:3”- and “18:3”-plant species

The fatty-acid composition of polar lipids from fruit and leaf chloroplasts was compared in five Solanaceous and two cucurbit species. The acylated fatty acids in monogalactosyl diglycerides (MGDG) from leaf chloroplasts of all five Solanaceous species included substantial amounts of ^7,10,13-hexadecatrienoic acid (16:3). In contrast, the MGDG from fruit chloroplasts of the Solanaceae contained very little of this plastid-specific polyunsaturate, and instead included a proportionately greater percentage of linoleic acid (18:2). In MGDG from leaf chloroplasts of two cucurbits, -linolenic acid (18:3) constituted 94–95% of the acylated fatty acids. Fruit-chloroplast galactolipids of the cucurbits had a greater abundance of 18:2, and hence a higher 18:2/18:3 ratio, than found in the corresponding leaf lipids. Among the phosphoglycerides, the unusual fatty acid 3-trans-hexadecenoate (trans-16:1) constituted from 15 to 24% of the acylated fatty acids in phosphatidyl glycerol (PG) from leaf chloroplasts (all species). In sharp contrast, trans-16:1 was virtually absent in PG from fruit chloroplasts of both Solanaceous and cucurbit species, and was replaced by a proportionate increase in the content of palmitate (16:0). The observed differences in the polar lipid fatty-acid composition of fruit and leaf chloroplasts are discussed in terms of the relative activity of several intrachloroplastic enzymes involved in lipid synthesis and fatty-acyl desaturation.Abbreviations MGDG monogalactosyldiglyceride - DGDG digalactosyl diglyceride - PC phosphatidyl choline - PE phosphatidyl ethanolamine - PG phosphatidyl glycerol     

Lipid and hydrocarbon compositions of a collection strain and a wild sample of the green microalga Botryococcus

Lipid composition and hydrocarbon structure of two colonial green algae of the genus Botryococcus, i.e., a museum strain and a field sample collected for the first time from Lake Shira (Khakasia, Siberia), have been compared. Polar lipids, diacylglycerols, alcohols, triacylglycerols, sterols, sterol esters, free fatty acids and hydrocarbons have been identified among lipids in the laboratory culture. The dominant fraction in the museum strain was formed by polar lipids (up to 50% of the lipids) made up of fatty acids from C₁₂ to C₂₄. Palmitic, oleic, C₁₆ - C₁₈ dienoic and trienoic acids were the main fatty acids of the museum strain. Aliphatic hydrocarbons were found in the lipid of the museum strain. However, these amounted maximally to about 1% of the dry biomass at the end of exponential growth phase. The qualitative and quantitative compositions of FAs and hydrocarbons of the museum strain of Botryococcus, (registered at the Cambridge collection as Botryococcus braunii Kutz No LB 807/1 Droop 1950 H-252) differed from those of the Botryococcus strain described in the literature as Botryococcus braunii. The Botryococcus sp. found in Lake Shira is characterized by a higher lipid content (<40% of the dry weight). Polar lipids, sterols, triacylglycerols, free fatty acids and hydrocarbons have been identified among lipids in the field sample. The main lipids in this sample were dienes and trienes (hydrocarbons <60% of total lipid). Monounsaturated and very long chain monounsaturated fatty acids, including C_28:1 and C_32:1 acids, were identified in the Botryococcus found in Lake Shira. The chemo-taxonomic criteria allow us to unequivocally characterize the organism collected from Lake Shira as Botryococcus braunii, race A.     

EFFECT OF GROWTH AND LIGHT/DARK CYCLES ON DIATOM LIPID CONTENT AND COMPOSITION1

Total extractable lipid (TEL) and lipid composition were studied throughout the growth cycle in three freshwater diatoms-Cyclotella meneghiniana Kütz., Melosira varians C. A. Ag., and Stephanodiscus binderanus (Kütz.) Krieg under three light regimes (16:8 h LD, 20:4 h LD, and 12:12 h LD) at 20°C. Two of the diatoms demonstrated strong daylength preferences for growth; C. meneghiniana grew best under long-day (20: 4-h LD) conditions, whereas S. binderanus grew best under short-day (12:12-h LD) conditions. The lipid composition of the diatoms was similar throughout the growth cycle. Aged (2-month-old) cells were high in total lipid and triacylglycerols. Before the onset of active growth and during the early part of active growth, there was a reduction in total neutral lipids, primarily triacylglycerols, and an increase in all polar lipids, including chlorophyll a, acetone-mobile polar lipids, and phospholipids. While cell numbers were still increasing, triacylglycerols increased and polar lipids decreased to levels near those found in aged cultures, Results suggest that increased triacylglycerol content of freshwater diatoms is not necessarily indicative of senescent populations.     

伴生细菌在入侵种桉树枝瘿姬小蜂克服桉树抗性中的作用

【目的】桉树枝瘿姬小蜂是我国近年来发现的一种主要危害桉属树种的外来有害生物。本研究旨在通过探究中国桉树枝瘿姬小蜂主要伴生细菌在桉树枝瘿姬小蜂成功定殖中的作用。【方法】测定不同抗性品系桉树的次生代谢物质黄酮和单宁的含量以及易感品系桉树在枝瘿姬小蜂危害前后的含量变化。通过体外抑菌和化学物质降解实验,探究桉树枝瘿姬小蜂主要伴生细菌对抗虫性物质黄酮和单宁的耐受性及降解能力。【结果】抗性品系桉树的黄酮和单宁的含量明显高于易感品系,易感品系在桉树枝瘿姬小蜂危害后黄酮和单宁的含量显著提高;高浓度的黄酮和单宁会抑制桉树枝瘿姬小蜂伴生细菌的生长,在中低浓度黄酮和单宁的条件下,主要伴生细菌能够适应,并继续繁殖;桉树枝瘿姬小蜂伴生细菌具有一定的降解黄酮和单宁的能力,其中细菌Staphylococcus cohnii降解黄酮的能力比Pseudomonas geniculate稍强,而Bacillus wiedannii、Serratia macescens对单宁具有较强的降解能力。【结论】桉树枝瘿姬小蜂侵染桉树后,可以诱导桉树产生抗性,桉树产生大量的次生代谢物质来抵御桉树枝瘿姬小蜂的危害,而桉树枝瘿姬小蜂部分伴生细菌可降解桉树次生代谢物质来帮助小蜂克服植物抗性完成定殖。     

Effect of growth temperature on ether lipid biochemistry in Archaeoglobus fulgidus

The archaea are distinguished by their unique isoprenoid ether lipids, which typically consist of the sn-2,3-diphytanylglycerol diether or sn-2,3-dibiphytanyldiglycerol tetraether core modified with a variety of polar headgroups. However, many hyperthermophilic archaea also synthesize tetraether lipids with up to four pentacyclic rings per 40-carbon chain, presumably to improve membrane thermal stability at temperatures up to∼110 °C. This study aimed to correlate the ratio of tetraether to diether core lipid, as well as the presence of pentacyclic groups in tetraether lipids, with growth temperature for the hyperthermophilic archaeon, Archaeoglobus fulgidus. Analysis of the membrane core lipids of A. fulgidus using APCI–MS analysis revealed that the tetraether-to-diether lipid ratio increases from 0.3 ± 0.1 for cultures grown at 70°C to 0.9 ± 0.1 for cultures grown at 89°C. Thin-layer chromatography (TLC) followed by APCI–MS analysis provided evidence for no more than one pentacycle in the hydrocarbon chains of tetraether lipid from cultures grown at 70°C and up to 2 pentacycles in the tetraether lipid from cultures grown at higher temperatures. Analysis of the polar lipid extract using TLC and negative-ion ESI–MS suggested the presence of diether and tetraether phospholipids with inositol, glycosyl, and ethanolamine headgroup chemistry.     

Occurrence and structure of lipoteichoic acids in the genus Staphylococcus

Lipoteichoic acids were isolated from eleven species of the genus Staphylococcus using phenol-water partition and hydrophobic chromatography on octyl-Sepharose CL-4B. The lipoteichoic acids purified could be visualized by SDS-PAGE. They were shown to be composed of a hydrophilic poly(glycerophosphate) chain covalently linked to gentiobiosyldiacylglycerol, the common lipid anchor of these molecules. Glycerophosphate units of the hydrophilic chain were found to be partly substituted with ester-linked d-alanine, except in the case of S. cohnii. The lipoteichoic acids isolated from S. cohnii, S. hominis, S. saprophyticus and S. simulans contain (1–2)-linked N-acetylglucosamine as an additional substituent of the poly(glycerophosphate) backbone.Abbreviations GLC gas-liquid chromatography - SDS-PAGE sodium dodecyl sulfate-polyacrylamide gel electrophoresis - TLC thin-layer chromatography     

Polar lipids and fatty acid composition ofThermus strains from New Zealand

The polar lipids and fatty acid composition ofThermus aquaticus YT-1 and YS 041,T. filiformis Wai33 A1 and eighteen isolates from New Zealand, several of which are attributed toT. filiformis, were compared to complement the taxonomy of these organisms. The polar lipid patterns were essentially similar in all strains and consisted of one major phospholipid and one major glycolipid. The fatty acid analysis produced three basic groups corresponding toT. filiformis Wai33 A1,T. aquaticus and the third to the other New Zealand strains. The presence of hydroxy fatty acids is reported inThermus spp. for the first time.     

Fatty acid composition in lipid fractions lengthwise the mycelium of Mortierella isabellina and lipid production by solid state fermentation

This paper investigates the correlation between mycelial age and fatty acid biosynthesis. The correlation was investigated by analyzing the lipid composition lengthwise the mycelium of the oleaginous fungus Mortierella isabellina, a potential producer of γ-linolenic acid (GLA). Young mycelia were rich in polar lipids (glycolipids plus sphingolipids and phospholipids), while neutral lipid content increased in aged mycelia. In young mycelia, each polar lipid fraction contained almost 40% (w/w) polyunsaturated fatty acids (PUFAs), but this content decreased to less than 30% (w/w) in aged mycelia. On the other hand, PUFA content in neutral lipids fluctuated slightly with age. These results indicate that PUFA biosynthesis is favored in young, fast growing mycelia, while it decreases significantly in aged mycelia. This trend was also observed when we grew M. isabellina on pear pomace, an agro-industrial waste. Pear pomace cultures yielded significant amounts of lipid, which reached 12% (w/w) in dry fermented mass. The produced lipid was rich in GLA and the maximum GLA content in dry fermented mass was 2.9 mg/g.