Degradation of long-chain n-alkanes by mucorales

Summary The composition of fatty acids in the lipids ofAbsidia spinosa, Cunninghamella echinulata, andMortierella isabellina was determined after growth on glucose and some n-alkanes. Mycelia metabolizing odd-carbon n-alkanes contained, among others, mono- and polyenoic heptadecanoic acids, that is, C_17:1(9)-, C_{17:2(9, 12)}-, and C_{17:3(6, 9, 12)}-acids. From the amounts of the isolated lipids it can be deduced thatAbsidia andCunninghamella may mainly degrade the alkanes in a terminal oxidation pathway whileMortierella prefers a subterminal way.Dedicated to Professor Dr. L. Acker on the occasion of his 65th birthday     

Microbiological Studies of Coli-aerogenes Bacteria

α-Ketoglutarate was obtained in a very small amount by the oxidative fermentation of acetate with either a growing culture or the washed cells of Escherichia coli. This microorganism was also observed to accumulate a considerable amount of α-ketoglutarate as the oxidation-product of C₄-dicarboxylic acids such as succinate, fumarate, malate and oxalacetate. The addition of acetate to the reaction mixtures containing either C₃- or C₄-acids brought about an increase in the yield of α-ketoglutarate. The bacteria of coli-aerogenes revealed an ability of oxidizing tricarboxylic acids under suitable conditions, but there was no noticeable production of α-ketoglutarate. The formation of glyoxylate was observed to occur during the degradation of citrate by the bacteria of coli-aerogenes. Finally, a cyclic mechanism of aerobic carbon-metabolism in the bacteria was propounded and discussed.     

1-Ethyl-3-methylimidazolium tolerance and intracellular lipid accumulation of 38 oleaginous yeast species

Pretreatment with ionic liquids (IL) such as 1-ethyl-3-methylimidazolium chloride or acetate is an effective method for aiding deconstruction of lignocellulosic biomass; however, the residual IL remaining in hydrolysates can be inhibitory to growth of ethanologenic or oleaginous yeasts that have been examined in the literature. The aim of this study was to identify oleaginous yeasts that are tolerant of the IL [C₂C₁Im][OAc] and [C₂C₁Im]Cl using 45 strains belonging to 38 taxonomically diverse species within phyla Ascomycota and Basidiomycota. Yeasts were cultivated in laboratory medium supplemented with 0, 2, or 4% IL in 96-well plates. The eight most tolerant strains were then cultivated in 10-mL media with no IL, 242mM [C₂C₁Im][OAc], or 242mM [C₂C₁Im]Cl. The effects of [C₂C₁Im]⁺ exposure on cell mass production and lipid accumulation varied at the species and strain level. The acetate salt decreased cell biomass and lipid production more severely than did the chloride ion for six strains. Lipid output was not markedly different (2.1 vs. 2.3 g/L) in Yarrowia lipolytica UCDFST 51-30, but decreased from 5 to 65% in other yeasts. An equimolar concentration of the chloride salt resulted in much milder effects, from 25% decrease to 66% increase in lipid output. The highest lipid outputs in this media were 8.3 and 7.9 g/L produced by Vanrija humicola UCDFST 10-1004 and UCDFST 12-717, respectively. These results demonstrated substantial lipid production in the presence of [C₂C₁Im]Cl at concentrations found in lignocellulosic hydrolysates, and thus, these two strains are ideal candidates for further investigation.

     

Die Fettsäuren in ganzen Zellen,Thylakoiden und Lipopolysacchariden von Rhodospirillum rubrum und Rhodopseudomonas capsulata

Zusammenfassung Die photosynthetischen Bakterien Rhodospirillum rubrum und Rhodopseudomonas capsulata wurden auf ihre Fettsäurezusammensetzung untersucht. Die Hauptfettsäuren von R. rubrum waren C_16:0 (11%), C_16:1 (30%) und C_18:1 (52%). Vaccensäure (C_18:1) bildete 94% der Fettsäuren von Rps. capsulata. Anaerobe Lichtzellen (thylakoidhaltig) unterschieden sich nicht in ihrem Fettsäuremuster von aeroben Dunkelzellen (thylakoidfrei). Gereinigte Thylakoide aus Lichtzellen zeigten das gleiche Fettsäuremuster wie die ganzen Zellen.Nach Phenol/Wasser-Extraktion der ganzen Zellen bei 68° C war bei beiden Organismen sowohl aus Licht- als auch aus Dunkelzellen eine Substanz aus der gäßrigen Phase isolierbar, welche in den Sedimentationseigenschaften mit den Lipopolysacchariden der Enterobacteriaceae übereinstimmte und nach orientierenden Untersuchungen Zucker enthält. Aus ihr wurde ein Fettsäuregemisch gewonnen, dessen Zusammensetzung von dem aus ganzen Zellen erheblich abwich. In Rps. capsulata enthielt es C_12:1 (40%) und C_16:0 (50%), während in R. rubrum sich das Fettsäuremuster über den Bereich von C₁₀ bis C₂₀ erstreckte. Licht- und Dunkelzellen wiesen in dieser Substanz Unterschiede in der Fettsäurezusammensetzung auf. Der quantitative Anteil der Fettsäuren in dieser Substanz, bezogen auf die Gesamtfettsäuren der Zelle, betrug in Licht- und Dunkelzellen 5–7%. Hydroxy-myristinsäure ließ sich in beiden Organismen nicht nachweisen.

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Fatty acid composition of whole cells, thylakoids and lipopolysaccharides of Rhodospirillum rubrum and Rhodopseudomonas capsulata

Summary The fatty acid composition of the photosynthetic bacteria Rhodospirillum rubrum and Rhodopseudomonas capsulata was investigated. The bulk of fatty acids of R. rubrum consisted of C_16:0 (11%), C_16:1 (30%), and C_18:1 (52%). The major fatty acid of Rps. capsulata was vaccenic acid (C_18:1), which accounted for 94% of the total fatty acids. Cells of both organisms, which were grown anaerobically in the light and fitted out with thylakoids had the same fatty acid composition as cells grown aerobically in the dark, which have no thylakoids.Purified thylakoids had the same fatty acid pattern as whole cells. Whole cells of light and dark cultures were extracted with phenol/water at 68° C. An opalizing fraction in the aqueous phase was sedimentable in the ultracentrifuge like the lipopolysaccharides of the Enterobacteriaceae. The pattern of fatty acids in this compound differed considerably from that of whole cells. The major fatty acids in this macromolecular fraction were C_12:1 (40%) and C_16:0 (50%) in Rps. capsulata, whereas in R. rubrum the whole range of fatty acids from C₁₀ to C₂₀ was demonstrable. Light and dark grown cells differed in the fatty acid composition of that compound. The fatty acid content of the extracted fraction accounted for 5–7% of the total fatty acids of whole cells. No hydroxymyristic acid could be identified in either R. rubrum or Rps. capsulata.

     

Effect of inorganic carbon supply on the photosynthetic physiology of Gracilaria tenuistipitata

Gracilaria tenuistipitata Zhang et Xia was cultured for 15 d at low, normal and high inorganic carbon concentrations under constant light, temperature and nutrient conditons. Carbonic anhydrase (CA; EC 4.2.1.1.) activity, ribulose-1,5-bisphosphate carboxylase/ oxygenase (Rubisco; EC 4.1.1.39) content, pigment content and C/N ratio were measured, and also the photosynthesis and growth rates. Both Rubisco content and CA activity increased under conditions of low inorganic carbon (C_i) but decreased at high C_i with respect to the control. The amount of pigments declined considerably at high C_i and was slightly higher at low C_i. The maximum rate of photosynthesis and the photosynthetic efficiency increased in low C_i and the opposite was found at high C_i concentration. The effects of C_i concentration on maximum rate of photosynthesis and photosynthetic efficiency are discussed in relation to the variation in pigment and Rubisco contents and CA activity. The data indicate that C_i may be an important factor controlling the photosynthetic physiology of G. tenuistipitata with regard, not only to the enzymes of C_i metabolism, but also to the pigment content.Abbreviations APS_max maximum apparent photosynthetic rate - CA carbonic anhydrase - Chl chlorophyll - C_i inorganic carbon - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase This work has been supported by grants No. PB91-0962 and No. MAR90-0365 from Spanish Direction for Science and Technology (DIGICYT). M.J. G-S holds a fellowship from the DIGICYT.     

C4-Dicarboxylic acid metabolism in bundle-sheath chloroplasts,mitochondria and strands of Eriochloa borumensis Hack., a phosphoenolpyruvate-carboxykinase type C4 species

C₄-acid metabolism by isolated bundlesheath chloroplasts, mitochondria and strands of Eriochloa borumensis Hack., a phosphoennolpyruvate-carboxykinase (PEP-CK) species, was investigated. Aspartate, oxaloacetate (OAA) and malate were decarboxylated by strands with several-fold stimulation upon illumination. There was strictly light-dependent decarboxylation of OAA and malate by the chloroplasts, but the chloroplasts did not decarboxylate aspartate in light or dark. PEP was a primary product of OAA or malate decarboxylation by the chloroplasts and its formation was inhibited by 3-(3,4-dichlorophenyl)-1, 1-dimethylurea or NH₄Cl. There was very little conversion of PEP to pyruvate by bundle-sheath chloroplasts, mitochondria or strands. Decarboxylation of the three C₄-acids by mitochondria was light-independent. Pyruvate was the only product of mitochondrial metabolism of C₄-acids, and was apparently transaminated in the cytoplasm since PEP and alanine were primarily exported out of the bundle-sheath strands. Light-dependent C₄-acid decarboxylation by the chloroplasts is suggested to be through the PEP-CK, while the mitochondrial C₄-acid decarboxylation may proceed through the NAD-malic enzyme (NAD-ME) system. In vivo both aspartate and malate are considered as transport metobolites from mesophyll to bundle-sheath cells in PEP-CK species. Aspartate would be metabolized by the mitochondria to OAA. Part of the OAA may be converted to malate and decarboxylated through NAD-ME, and part may be transported to the chloroplasts for decarboxylation through PEP-CK localized in the chloroplasts. Malate transported from mesophyll cells may serve as carboxyl donor to chloroplasts through the chloroplastic NAD-malate dehydrogenase and PEP-CK. Bundle-sheath strands and chloroplasts fixed ¹⁴CO₂ at high rates and exhibited C₄-acid-dependent O₂ evolution in the light. Studies with 3-mercaptopicolinic acid, a specific inhibitor of PEP-CK, have indicated that most (about 70%) of the OAA formed from aspartate is decarboxylated through the chloroplastic PEP-CK and the remaining (about 30%) OAA through the mitochondrial NAD-ME. Pyruvate stimulation of aspartate decarboxylation is discussed; a pyruvate-alanine shuttle and an aspartate-alanine shuttle are proposed between the mesophyll and bundle-sheath cells during aspartate decarboxylation through the PEP-CK and NAD-ME system respectively.Abbreviations CK carboxykinase - -Kg -ketoglutarate - ME malic enzyme - 3-MPA 3-mercaptopicolinic acid - OAA oxaloacetate - PEP phosphoenolpyruvate - R5P ribose-5-phosphate     

Plasmodesmata between mesophyll and bundle sheath cells in relation to the exchange of C4-acids

Summary In the C₄ species Salsola kali L. the frequency of plasmodesmata in the wall between mesophyll and bundle sheath cells has been determined with great precision by the use of transmission and scanning electron microscopy. The frequency of 14×10⁸ cm^-2 is rather high compared to values from other plant tissues, but if it is assumed that the postulated exchange of C₄-acids occur in the desmotubulus of the plasmodesmata, the fraction of the mesophyll-bundle sheath interface occupied by plasmodesmatal pores is 10-10² times smaller than previously thought.Abbreviations TEM transmission electron microscopy - SEM Scanning electron microscopy     

Structural modification of Escherichia coli lipid A by myristoyltransferase gene from Klebsiella pneumoniae

Lipid A in lipopolysaccharide (LPS) of Escherichia coli mutant strains was modified by the introduction of myristoyltransferase gene cloned from Klebsiella pneumoniae. When the gene was introduced into the mutant having lipid A containing only 3‐hydroxymyristic acids, it produced lipid A with two additional myristic acids (C_14:0). When the same gene was introduced into the mutant with pentaacylated lipid A containing one lauric acid (C_12:0), C_12:0 was replaced by C_14:0. IL‐6‐inducing activity of LPS with modified lipid A structure suggested that C_12:0 in lipid A could be replaced by C_14:0 without changing the immunostimulating activity.     

The intracellular blue pigment of Pseudomonas lemonnieri

Summary The large-scale production, isolation, and purification are described of the blue insoluble intracellular pigment of the bacterium Pseudomonas lemonieri. The pigment, C₂₆H₃₇N₅O₆, occurs in the cells as a salt (cation unknown) of 6-octanoylamino-3-hydroxy-2-aza-benzoquinone-(1,4)-4-[5-octanoylamino-2,6-dihydroxy-pyridyl-(3)-imide] (I). Nitric acid oxidation of pigment I yields IV, 6-octanoylamino-3-hydroxy-2-aza-benzoquinone-(1,4). Further hydrolysis of IV splits off n-octanoic acid, which is free of homologues. The structures given for the pigment and its degradation products have been proven by identification with authentic preparations.Although they have different chromophores, the pigment (I) of Pseudomonas lemonnieri and N,N-dioctanoyl-indigoidine (VI) nevertheless resemble one another in IR-absorbances, NMR-spectra, and chromatographic behavior, because of homogeneous functional groups and ring structures. I and VI are indeed chemically related, as can be seen from the facts that aminocitrazinic acid is a common starting material for the in vitro syntheses of both compounds, and that the diazaindophenol (I) can be converted to the diaza-diphenoquinone (VI) by hydrogenation and subsequent autoxidation.Dedicated with devotion and admiration to Professor C. B. Van Niel on his seventieth birthday.     

A two-component sex attractant for males of the geometrid moth Alsophila quadripunctata

The binary mixture of the hydrocarbons (3Z,6Z,9Z)-3,6,9-nonadecatriene and (6Z,9Z)-6,9-nonadecadiene is a sex attractant for males of Alsophila quadripunctata Esp. (Lepidoptera, Geometridae). Triene/diene ratios from 1:1 to 1:0.01 attracted males in the field, the ratios 1:1 and 1:0.7 were most effective. The triene on its own also attracted males, but in significantly lower numbers than the 1:1 mixture. In a dosage test the highest dose, 1800 g of 1:0.8 [triene:diene] mixture applied to rubber caps was most effective. This is the first report of a geometrid sex attractant with field activity containing more than one component.

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Zusammenfassung Die binäre Mischung der Kohlenwasserstoffe (3Z,6Z,9Z)-3,6,9-Nonadecatrien [ZZZ3,6,9-19:H] und (6Z,9Z)-6,9-Nonadecadien [ZZ6,9-19:H] in den Verhältnissen 1:1 bis 1:0.01 erwies sich im Freiland als Sexuallockstoff für Männchen von Alsophila quadripunctata (Geometridae, Lepidoptera). Dabei besaß die 1:1-Mischung die beste Fängigkeit, das Nonadecatrien allein lockte schlechter, während das C₁₉-Alkadien unwirksam war. Ein Dosiswirksamkeitstest ergab bei Köderbeladungen von 1.8 mg (Trien:Dien + 1:0.8) die besten Fangergebnisse. Im Verlauf der Untersuchungen wurden weitere zwölf geometrische-oder positionsisomere C₁₉-Polyenkohlenwasserstoffe getestet, wobei keine der geprüften Verbindungen Attraktant-oder Inhibitorwirkung zeigte.

     

High‐titer production and strong antimicrobial activity of sophorolipids from Rhodotorula bogoriensis

Rhodotorula bogoriensis produces sophorolipids (SLs) that contain 13‐hydroxydocosanoic acid (OH‐C₂₂) as the lipid moiety. A systematic study was conducted to further understand the fermentative production of SLs containing OH‐C₂₂ (C₂₂‐SL) by R. bogoriensis. Shake‐flask studies showed that R. bogoriensis consumed glucose at a slow pace. HPLC analysis of the C₂₂‐SL products from shake‐flask fermentations at different glucose concentrations showed a correlation between glucose depletion and the extent of C₂₂‐SL deacetylation. A large‐scale bioreactor fermentation resulted in the isolation of C₂₂‐SL at a volumetric product yield of 51 g/L. HPLC analysis of C₂₂‐SL product from the bioreactor fermentation corroborated the finding that glucose depletion correlated with extensive deacetylation of C₂₂‐SL. The antimicrobial activity of C₂₂‐SL was established for the first time to be stronger than the C₁₈‐SL from Candida bombicola against Propionibacterium acnes in a plate assay. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:867–874, 2015     

The major carotenoid in all known species of heliobacteria is the C30 carotenoid 4,4′-diaponeurosporene, not neurosporene

The carotenoids of five species of heliobacteria (Heliobacillus mobilis, Heliophilum fasciatum, Heliobacterium chlorum, Heliobacterium modesticaldum, and Heliobacterium gestii) were examined by spectroscopic methods, and the C₃₀ carotene 4,4′-diaponeurosporene was found to be the dominant pigment; heliobacteria were previously thought to contain the C₄₀ carotenoid neurosporene. In addition, trace amounts of the C₃₀ diapocarotenes diapolycopene, diapo-ζ-carotene, diapophytofluene, and diapophytoene were also found. Up to now, diapocarotenes have been found in only three species of chemoorganotrophic bacteria, but not in phototropic organisms. Furthermore, the esterifying alcohol of bacteriochlorophyll g from all known species of heliobacteria was determined to be farnesol (C₁₅) instead of the usual phytol (C₂₀). Heliobacteria may be unable to produce geranylgeranyol (C₂₀). Received: 10 March 1997 / Accepted: 3 June 1997     

Wax esters of the new zealand silver fern,Cyathea dealbata

The New Zealand silver fern epicuticular wax contained wax esters (C₃₈–C₆₀) of which the C₄₀–C₅₂ homologues were shown by capillary column GC/MS to comprise C₂₂–C₃₄ even and odd n-alkanols randomly combined with C₁₆–C₂₄ even n-acids.     

A multivariate analysis of health risk assessment,phytoremediation potential,and biochemical attributes of Spinacia oleracea exposed to cadmium in the presence of organic amendments under hydroponic conditions

Abstract

Cadmium (Cd) phytoremediation potential and its accumulation in edible and nonedible plant tissues is the function of various biochemical processes taking place inside plants. This study assessed the impact of organic ligands on Cd phyto uptake and different biophysiochemical processes of Spinacia oleracea L., and associated health hazards. Plants were exposed to Cd alone and chelated with citric acid (CA) and ethylenediaminetetraacetic acid (EDTA). Results revealed that the effect of Cd on lipid peroxidation, H₂O₂ production and pigment contents varied greatly with its applied level and the type of organic ligand. Moreover, the effect was more prominent in root tissues than leaf tissues and for high concentrations of Cd and organic ligands. Cadmium accumulation increased by 90 and 74% in roots and leaves, respectively, with increasing Cd levels (25–100?µM). Cadmium exposure at high levels caused lipid peroxidation in roots only. Application of both CA and EDTA slightly diminished Cd toxicity with respect to pigment contents, lipid peroxidation and hydrogen peroxide (H₂O₂) contents. Hazard quotient (HQ) of Cd was <1.00 for all the treatments. Under nonlinear effect of treatments, multivariate analysis can be an effective tool to trace overall effects/trends.     

Red (hot) algae: modulation of mono- and digalactosyldiacylglycerol-associated fatty acids of Polysiphonia sp. and Porphyridium sp. in response to growth temperature

ABSTRACT

There is a dearth of surveys examining the direct effects of temperature on red algal galactolipids, and none which examine regiochemistry modulation with respect to growth temperature. Therefore, forms of monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), the two most commonly found galactolipids in chloroplast membranes, were determined in two model red algae, Polysiphonia sp. and Porphyridium sp., via positive-ion electrospray ionization/mass spectrometry (ESI/MS) and ESI/MS/MS. We sought to compare modulation of galactolipid forms in response to growth temperature between these two red algae and selected descendants with red algal plastid ancestry, and have proposed the following hypothesis: Polysiphonia sp. and Porphyridium sp. would modulate desaturations in the sn-2 position in accordance with previously examined descendant organisms. It was observed that both red algae produced C₂₀/C₁₆ (sn-1/sn-2 regiochemistry) and C₂₀/C₂₀ forms of MGDG and DGDG as their most abundant galactolipids under two growth temperatures, 20°C and 30°C. Furthermore, temperature-induced modulation of the major forms of MGDG and DGDG was more complex than what has been observed previously in selected representatives of red algal plastid ancestry. Porphyridium sp. modulated levels of desaturation in the sn-1 position of C₂₀/C₁₆ forms of MGDG and DGDG and in the sn-1 and sn-2 positions of C₂₀/C₂₀ forms of MGDG and DGDG. Polysiphonia sp. displayed trends suggesting it modulates levels of desaturation in the sn-1 and sn-2 positions of C₂₀/C₂₀ forms of MGDG and DGDG, thus indicating a different approach to regulating plastid membrane fluidity from that which has been observed in algae with secondary, red algae-derived plastids.     

Untersuchungen an Beauveria tenella (NRRL 2334, 2335, 2336; bisher Agaricus campestris)

Zusammenfassung Die physikalischen und chemischen Kennzahlen und Daten des durch Ätherextraktion gewonnenen Rohlipids von Beauveria tenella wurden bestimmt und spektrale Absorptionskurven aufgenommen.Die Methylester der Fettsäuren wurden gaschromatographisch analysiert. Die einzelnen Fettsäuren wurden identifiziert und ihr mengenmäßiger Anteil ermittelt.Etwa 90% der Fettsäuren haben eine Kettenlänge von 16–18 Kohlenstoffatomen. Nahezu 60% der Fettsäuren sind ungesättigt; der prozentuale Anteil dieser Säuren nimmt mit steigender Zahl der Doppelbindungen ab.Octadecensäure hatte mit 25,6% den größten Anteil an der Gesamtmenge.An seltenen Fettsäuren konnte unter anderem eine gesättigte C₁₇- und C₂₄-Fettsäure nachgewiesen und das Vorkommen einer gesättigten C₁₉-und C₂₁-Fettsäure wahrscheinlich gemacht werden.

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Summary The physical and chemical constants and the spectral absorption curves of crude lipids of Beauveria tenella, obtained by means of etherextraction, were determined.The methyl esters of the fatty acids were analyzed using gas-liquid chromatography. The individual fatty acids were identified and the amount of each in the complete sample determined.Approximately 90% of the fatty acids had a 16–18 carbon-chain length, while almost 60% of the fatty acids were unsaturated. The percentage of fatty acids with unsaturated bonds was reciprocally proportional to the number of double bonds present.Octadecenoic acid comprised 25,6% of the total fatty acids and represented the largest single amount of a specific fatty acid present.With respect to unusual fatty acids, a saturated C₁₇ and a C₂₄ fatty acid were identified, while the presence of a C₁₉ and a C₂₁ fatty acid was indicated.

     

Carbon:nitrogen ratio interacts with initial concentration of total solids on insecticidal crystal protein and spore production in Bacillus thuringiensis HD-73

A response-surface methodology was used to study the effect of carbon:nitrogen ratio (C:N) and initial concentration of total solids (C _TS) on insecticidal crystal protein production and final spore count. Bacillus thuringiensis var. kurstaki HD-73 was grown in a stirred-tank reactor using soybean meal, glucose, yeast extract, corn steep solids and mineral salts. Soybean meal and glucose were added according to a central composite experimental design to test C:N ratios ranging from 3:1 to 11:1 and C _TS levels from 60␣g/l to 150 g/l. Cry production was quantified using sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The response-surface model, adjusted to the data, indicated that media with a C:N of 7:1 yielded the highest relative Cry production at each C _TS. The spore count was higher at low C:N ratio (4:1) and high C _TS (near 150 g/l). Specific Cry production varied from 0.6 to 2.2 g Cry/10¹⁰ spores. A 2.5-fold increase in C _TS resulted in a six-fold increase of protoxin production at a 7:1 C:N ratio. It is concluded that the best production conditions for Cry and for spores are different and optimization of B. thuringiensis processes should not be done on a spore-count basis but on the amount of Cry synthesized. Received: 5 September 1997 / Received revision: 22 December 1997 / Accepted: 2 January 1998     

Characterization of marine microalga, Scenedesmus sp. strain JPCC GA0024 toward biofuel production

A marine microalga, strain JPCC GA0024 was selected as high amount of neutral lipid producers from marine microalgal culture collection toward biofuel production. The strain was tentatively identified as Scenedesmus rubescens by 18S rDNA analysis. The growth of strain JPCC GA0024 was influenced by artificial seawater concentrations. The optimum growth of 0.79 g/l was obtained at 100% artificial seawater. The lipid accumulation reached 73.0% of dry cell weight at 100% artificial seawater without additional nutrients for 11 days. Gas chromatography/mass spectrometry analysis indicates that lipid fraction mainly contained hydrocarbons including mainly hexadecane (C₁₆ H₃₄) and 1-docosene (C₂₂ H₄₄). Furthermore, calorimetric analysis revealed that the energy content of strain JPCC GA0024 was 6,160 kcal/kg (25.8 MJ/kg) of calorific value, which was equivalent to the coal engery. The strain JPCC GA0024, S. rubescens, will become a promising resource that can grow as a dominant species in the seawater for the production of both liquid and solid biofuels.     

Characterization of a non-pigment producing Monascus purpureus mutant strain

A characterization of a non-pigment producing mutant Monascus purpureus M₁₂ compared with its parental strain Monascus purpureus Went CBS 109.07 has been performed aiming to investigate the relation between pigment biosynthesis and other characteristics of these fungi. A comparison has been made of morphological features, some physiological properties and biochemical activities of both strains. The albino mutant exhibits an anamorph life cycle, high conidia forming capability, slower radial growth rate and temperature sensitivity. The assimilation capacity of both strains for mono-, disaccharides and some alcohols is in the same range (Y_X/C 0.2 – 0.35), while the red strain has a higher fermentation capacity. In a selected albino mutant, the growth rate, metabolic activity and capacity for production of typical for Monascus fungi secondary metabolites were reduced considerably. Hydrolytic activity towards natural substrates expressed through glucoamylase and protease was approximately 10 fold lower in the non pigment producing strain (0.05 – 0.08 U/mg protein and 0.01 – 0.07 U/mg protein respectively) compared with the red one. Important qualitative differences between both strains was found in fatty acid composition and in the production of citrinin and monacolin. The mutant strain possessed C₁₇, C₂₀ and C₂₂ fatty acids and did not produce citrinin. This revised version was published online in June 2006 with corrections to the Cover Date.     

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.