Oxygen transfer rate and sophorose lipid production by Candida bombicola.

Sophorose lipids (SLs) have applications as surfactants and are produced at high levels by several yeasts. We developed a fed-batch shake-flask method for the production of SLs by Candida bombicola ATCC 22214. Optimal aeration, expressed in terms of oxygen transfer rate, was between 50 and 80 mM O(2)/L h(-1) and resulted in maximum values for both volumetric product formation (1-1.5 g/L h(-1)) and SL yield (350 g/L). The lowest aeration levels resulted in the enrichment in saturated fatty acid SLs at the expense of unsaturated fatty acid SLs.     

Influence of substrate supply on the production of sophorose lipids by Candida bombicola ATCC 22214

Summary Candida (Torulopsis) bombicola ATCC 22214 produces 180 g/l sophorose lipids using glucose and oleic acid (technical grade) as combined substrates in an extended fed-batch cultivation. Excess of oleic acid generated a paste-like product. However, only when oleic acid was not detectable during the whole run of cultivation, a microcrystalline product precipitated. The unsaturated C-18 fatty acids of the technical grade oleic acid were transferred unchanged into the sophorose lipid.     

Effect of soybean oil and glucose on sophorose lipid fermentation by Torulopsis bombicola in continuous culture

The effect of soybean oil and glucose on the growth of Torulopsis bombicola and sophorose lipid production in continuous culture was investigated. As the dilution rate in 100 g/l glucose and 100 g/l soybean oil medium was increased, the dry cell weight and sophorose lipid concentration decreased. Sophorose lipid productivity, however, was maximum at a dilution rate of 0.03 h⁻¹. The cell yield from glucose and the sophorose lipid production from soybean oil were approximately constant regardless of the dilution rate. The specific consumption rate of soybean oil was closely related to the specific production rate of sophorose lipid. These results suggest that soybean oil was used only for sophorose lipid production whereas glucose was used only for cell mass and maintenance. When the soybean oil concentration was varied at fixed dilution rate in 100 g/l glucose medium, a high concentration of soybean oil was found to inhibit sophorose lipid production. Received: 9 January 1997 / Received revision: 5 March 1997 / Accepted: 13 April 1997     

Redirecting the lipid metabolism of the yeast Starmerella bombicola from glycolipid to fatty acid production

Journal of Industrial Microbiology & Biotechnology - Free fatty acids are basic oleochemicals implemented in a range of applications including surfactants, lubricants, paints, plastics, and...     

The effect of medium composition on the structure and physical state of sophorolipids produced by Candida bombicola ATCC 22214

Candida bombicola was grown using a variety of lipophilic carbon substrates. Most of the hydrocarbon and carboxylic acid substrates resulted in a mixture of sophorolipids consisting of free acids and the more desirable lactones. The ratio of diacylated lactone to free acid in these mixtures was a maximum when produced using hexadecane and heptadecane. All of the other lipophilic substrates resulted in significant amounts of free acids being produced. These lactone products were unique in that they precipitated as crystals, which were easily separated from the culture medium. All of the other products were isolated as oils as is usually reported in the literature. Finally, the amounts of these crystals recovered were significantly higher than those observed for any of the oily products. It was possible to determine the degree of direct incorporation of the lipophilic substrates into the sophorolipids for a homologous series of alkanes. The amount of direct incorporation increased with increasing chain length to a maximum for pentadecane, hexadecane and heptadecane. As the length of the alkane substrate increased further, the amount of direct incorporation then decreased until there was no apparent incorporation for eicosane.     

Influence of low cholesterol eggs enriched with vitamin-E and omega-3 fatty acid on blood lipid profile of Wistar rats

In the recent past, low cholesterol eggs enriched with vitamin-E and omega-3 fatty acid have been developed and are marketed under different brands claiming them as heart friendly. The influence of these eggs (smart eggs) on lipid profile of rats was evaluated in comparison to that of the standard eggs. Data of 4 week dietary treatment revealed that total plasma cholesterol, low density lipoprotein (LDL) and very low density lipoprotein (VLDL) cholesterol increased only 22% in rats fed on diet containing 4 smart eggs per kg of semi-synthetic diet in contrast to the increase of more than 100 % when fed on diet containing standard eggs. The results suggest that it is not the low cholesterol content alone but also vitamin E and omega-3 fatty acids present in smart eggs that act synergically to prevent a substantial change in blood lipid profile and impose no serious risk to the health of the consumers.     

Candida bombicola cells immobilized on patterned lipid films as enzyme sources for the transformation of arachidonic acid to 20-HETE

Preparation of biocompatible surfaces for immobilization of enzymes and whole cells is an important aspect of biotechnology due to their potential applications in biocatalysis, biosensing, and immunological applications. In this report, patterned thermally evaporated octadecylamine (ODA) films are used for the immobilization of Candida bombicola cells. The attachment of the cells to the ODA film surface occurs possibly through nonspecific interactions such as hydrophobic interactions between the cell walls and the ODA molecules. The enzyme cytochrome P450 present in the immobilized yeast cells on the ODA film surface was used for the transformation of the arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE). The assembly of cells on the hydrophobic ODA surface was confirmed by quartz crystal microgravimetry (QCM), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). SEM images confirmed the strong binding of the yeast cells to the ODA film surface after biocatalytic reactions. Moreover, the biocomposite films could be easily separated from the reaction medium and reused.     

Characteristic lipids of Bordetella pertussis: simple fatty acid composition, hydroxy fatty acids, and an ornithine-containing lipid.

The lipids and fatty acids of Bordetella pertussis (phases I to IV) were analyzed by thin-layer chromatography, gas-liquid chromatography, and mass spectrometry and compared with those of B. parapertussis and B. bronchiseptica. The major lipid components of the three species were phosphatidylethanolamine, cardiolipin, phosphatidylglycerol, lysophosphatidylethanolamine, and an ornithine-containing lipid. The ornithine-containing lipid was characteristic of the genus Bordetella. The fatty acid composition of the total extractable cellular lipids of B. pertussis was mostly hexadecanoic and hexadecenoic acids (90%) in a ratio of about 1:1. The hexadecenoic acid of B. pertussis was in the cis-9 form. The fatty acid composition of the residual bound lipids was distinctly different from that of the extractable lipids, and residual bound lipids being mainly 3-hydroxytetradecanoic, tetradecanoic, and 3-hydroxydecanoic acids, with 3-hydroxydodecanoic acid occurring in some strains. It was determined that the 3-hydroxy fatty acids were derived from lipid A. The fatty acid composition of the total extractable cellular lipids of B. parapertussis and B. bronchiseptica, mainly composed of hexadecanoic and heptadecacyclopropanoic acid, differed from that of B. pertussis. Although the fatty acid composition of the residual bound lipids of B. parapertussis was similar to that of the residual bound lipids of B. pertussis, 2-hydroxydodecanoic acid was detected only in the bound lipids of B. bronchiseptica.     

Influence of ethanol on the lipid content and fatty acid composition ofSaccharomyces cerevisiœ

The content of total lipid as well as of ergosterol, squalene, and major fatty acids were compared in the cells of a distillery strain ofSaccharomyces cerevisiœ incubated for 3, 48 and 120 h in the presence of 5, 10 and 15% ethanol. Ethanol induced lipid accumulation with preferential ergosterol biosynthesis. The relative contents of palmitic and stearic acid decreased whereas the amount of palmitoleic and oleic acid increased. The total content of all fatty acids rose as a consequence of the ethanol treatment.     

Production of new-to-nature sophorolipids by cultivating the yeast Candida bombicola on unconventional hydrophobic substrates

The naturally occurring sophorolipids synthesized by Candida bombicola possess--despite their overall heterogeneity--little variation in the length of the lipid tail. The range is limited to C16-C18 fatty acids and is governed by the specificity of a cytochrome P450 monooxygenase. However, incorporation of fatty acids differing from the conventional C16-C18 range could broaden up the application potential of sophorolipids. The incorporation of medium-chain fatty acids should render the molecules more hydrophilic and consequently improve their water solubility. Two strategies to circumvent this C16-C18 preference are described in this paper. The first one skips the controlling action of the cytochrome P450 enzyme by supplying the yeast with already hydroxylated substrates, while the other method is based on the deception of the enzyme by presenting it substrates structurally resembling stearic acid. This later strategy can be applied to create very specific tailor-made sophorolipids when combined with post-fermentive modification.     

Effect of fish and fish oil-derived omega-3 fatty acids on lipid oxidation

There is evidence that omega-3 (omega3) fatty acids derived from fish and fish oils reduce the risk of cardiovascular disease via mechanisms underlying atherosclerosis, thrombosis and inflammation. Despite these benefits, there has been concern that these fatty acids may increase lipid peroxidation. However, the in vivo data to date are inconclusive, due in part to limitations in the methodologies. In this regard, our findings using the measurement of F(2)-isoprostanes, a reliable measure of in vivo lipid peroxidation and oxidant stress, do not support adverse effects of omega3 fatty acids on lipid peroxidation.     

Synergistic effects of stress and omega-3 fatty acid deprivation on emotional response and brain lipid composition in adult rats

The aim was to determine the consequences of multi-generational n-3 polyunsaturated fatty acids (PUFA) deficiency on emotional response in rats subjected to maternal separation (MS) as chronic early life stress. Pups fed a control or an n-3 PUFA deficient diet were daily separated for 2 weeks before weaning. In adult rats, reward response was assessed by sucrose consumption and reactivity to novelty using openfield test. Both n-3 PUFA deficiency and MS increased reward response and impulsivity. Moreover, nutritional deficiency and stress acted in synergy to elevate sucrose intake by 80%, compared to control conditions. n-3 PUFA deprivation induced a depletion of docosahexanoeic acid of brain membranes by 70% compensated by increase in 22:5 n-6 and arachidonic acid (AA) levels. The diet-induced AA increase was, however, significantly higher in MS rats. This suggests that n-3 PUFA deficit could be an environmental risk increasing vulnerability to depressive-like response induced by chronic stress.