In vitro evaluation of “horchata” co-products as carbon source for probiotic bacteria growth

Tiger nut milk (“horchata”) liquid co-products (TNLC) were evaluated as carbon source for probiotic bacteria (Lactobacillus acidophilus and Bifidobacterium animalis) growth by screening via microplate assay and determination of viable cells and metabolic activity. Based on MRS five different basal media were prepared ((i) without carbon source, (ii) with 2% (w/v) glucose, (iii) with 2% (w/v) FOS, (iv) with 2% (v/v) TNLC and (v) 3% (v/v) TNLC). Additionally, reconstituted TNLC was also used as basal medium. For determination of viable cells and metabolic activity skim milk powder was used. Glucose was found to be the best substrate to L. acidophilus grows, followed by FOS and TNLC (2% and 3%, respectively). TNLC (3%) was found to be the best substrate followed by TNLC (2%), glucose and FOS, in the promotion of growth of B. animalis. The growth of L. acidophilus and B. animalis in skim milk reconstituted TNLC + water was higher than samples inoculated in skim milk reconstituted only with water (p < 0.05). This is supported by the pH effect and by the faster organic acid production (mainly lactic acid, acetic acid, and butyric acid), confirming the property of TNLC as a carbon source for probiotic bacteria growth.     

Medium Optimization for Exopolysaccharide Production in Liquid Culture of Endophytic Fungus Berkleasmium sp. Dzf12

Berkleasmium sp. Dzf12, an endophytic fungus from Dioscorea zingiberensis, is a high producer of spirobisnaphthalenes with various bioactivities. The exopolysaccharide (EPS) produced by this fungus also shows excellent antioxidant activity. In this study, the experimental designs based on statistics were employed to evaluate and optimize the medium for EPS production in liquid culture of Berkleasmium sp. Dzf12. For increasing EPS yield, the concentrations of glucose, peptone, KH₂PO₄, MgSO₄·7H₂O and FeSO₄·7H₂O in medium were optimized using response surface methodology (RSM). Both the fractional factorial design (FFD) and central composite design (CCD) were applied to optimize the main factors which significantly affected EPS production. The concentrations of glucose, peptone and MgSO₄·7H₂O were found to be the main effective factors for EPS production by FFD experimental analysis. Based on the further CCD optimization and RSM analysis, a quadratic polynomial regression equation was derived from the EPS yield and three variables. Statistical analysis showed the polynomial regression model was in good agreement with the experimental results with the determination coefficient (adj-R²) as 0.9434. By solving the quadratic regression equation, the optimal concentrations of glucose, peptone and MgSO₄·7H₂O for EPS production were determined as 63.80, 20.76 and 2.74 g/L, respectively. Under the optimum conditions, the predicted EPS yield reached the maximum (13.22 g/L). Verification experiment confirmed the validity with the actual EPS yield as 13.97 g/L, which was 6.29-fold in comparison with that (2.22 g/L) in the original basal medium. The results provide the support data for EPS production in large scale and also speed up the application of Berkleasmium sp. Dzf12.     

Enhancement of Palmarumycins C12 and C13 Production in Liquid Culture of Endophytic Fungus Berkleasmium sp. Dzf12 after Treatments with Metal Ions

The influences of eight metal ions (i.e., Na⁺, Ca²⁺, Ag⁺, Co²⁺, Cu²⁺, Al³⁺, Zn²⁺, and Mn⁴⁺) on mycelia growth and palmarumycins C₁₂ and C₁₃ production in liquid culture of the endophytic fungus Berkleasmium sp. Dzf12 were investigated. Three metal ions, Ca²⁺, Cu²⁺ and Al³⁺ were exhibited as the most effective to enhance mycelia growth and palmarumycin production. When calcium ion (Ca²⁺) was applied to the medium at 10.0 mmol/L on day 3, copper ion (Cu²⁺) to the medium at 1.0 mmol/L on day 3, aluminum ion (Al³⁺) to the medium at 2.0 mmol/L on day 6, the maximal yields of palmarumycins C₁₂ plus C₁₃ were obtained as 137.57 mg/L, 146.28 mg/L and 156.77 mg/L, which were 3.94-fold, 4.19-fold and 4.49-fold in comparison with that (34.91 mg/L) of the control, respectively. Al³⁺ favored palmarumycin C₁₂ production when its concentration was higher than 4 mmol/L. Ca²⁺ had an improving effect on mycelia growth of Berkleasmium sp. Dzf12. The combination effects of Ca²⁺, Cu²⁺ and Al³⁺ on palmarumycin C₁₃ production were further studied by employing a statistical method based on the central composite design (CCD) and response surface methodology (RSM). By solving the quadratic regression equation between palmarumycin C₁₃ and three metal ions, the optimal concentrations of Ca²⁺, Cu²⁺ and Al³⁺ in medium for palmarumycin C₁₃ production were determined as 7.58, 1.36 and 2.05 mmol/L, respectively. Under the optimum conditions, the predicted maximum palmarumycin C₁₃ yield reached 208.49 mg/L. By optimizing the combination of Ca²⁺, Cu²⁺ and Al³⁺ in medium, palmarumycin C₁₃ yield was increased to 203.85 mg/L, which was 6.00-fold in comparison with that (33.98 mg/L) in the original basal medium. The results indicate that appropriate metal ions (i.e., Ca²⁺, Cu²⁺ and Al³⁺) could enhance palmarumycin production. Application of the metal ions should be an effective strategy for palmarumycin production in liquid culture of the endophytic fungus Berkleasmium sp. Dzf12.     

Cost-cutting of nitrogen source for economical production of cellulolytic enzymes by Trichoderma inhamatum KSJ1

For saccharifying food wastes, cellulolytic enzymes were produced using Trichoderma inhamatum KSJ1 in modified Mandel’s medium. In a previous study, 0.1% bacto peptone in Mandel’s medium was established as the best organic nitrogen source for the production of cellulolytic enzymes using strain KSJ1. However, economically, peptone was too expensive. Therefore, soybean, yeast and Chunggookjang (fermented soybean paste) were substituted for peptone in this research. Also, yeast or ground soybean hydrolyzed by sulfuric acid or from a culture broth of Bacillus alcalophilus, a strain producing protease, was added to the medium as the nitrogen source to the production of cellulolytic enzyme. In the cultivation using 0.5% yeast hydrolyzed with a culture solution of B. alcalophilus as the nitrogen source, the activities of FPase and amylase were 0.20 and 2.17 U/mL in a 100 mL flask, compared to 0.35 and 1.24 U/mL with the 0.1% peptone as control, respectively. In a 10 L jar fermenter, the activities of FPase and amylase were improved to 0.40 and 4.82 U/mL in the cultivation, respectively, using 0.5% yeast hydrolyzed with the culture broth, compared with 0.38 and 3.79 U/mL, respectively, for the 0.1% peptone as control. Therefore, hydrolyzed yeast was established as an available nitrogen source for the industrial scale production of cellulolytic enzymes by strain KSJ1, resulting in a 52.3% cost reduction in the production of cellulolytic enzyme by substitution of the expensive nitrogen sources.     

Achieving the Best Yield in Glycolipid Biosurfactant Preparation by Selecting the Proper Carbon/Nitrogen Ratio

Pseudomonas aeruginosa RS29, the native biosurfactant-producing strain isolated from the oil fields of Assam, India was used to investigate the influence of the carbon nitrogen ratio on production of the biosurfactant. The biosurfactant producing ability of the strain was measured based on surface tension (ST) reduction of the culture medium and the emulsification (E24) index. Production was greatly influenced by the sources of nitrogen and carbon as well as the carbon to nitrogen (C/N) ratio. Sodium nitrate was the best nitrogen source and the water miscible carbon source, glycerol was observed as the best carbon source for maximum biosurfactant production. The C/N ratio 12.5 allowed the maximum production of biosurfactant by the RS29 strain. At this C/N ratio, 55 % ST of the culture medium was reduced by the produced biosurfactant. Concentrations of crude and rhamnolipid biosurfactant obtained at this particular C/N ratio were 5.6 and 0.8 g/l respectively. The RS29 strain was novel as it was able to produce a sufficient amount of biosurfactant utilizing a much lower amount of the water miscible carbon source, glycerol. Extraction of the biosurfactant by a chloroform–methanol (2:1) mixture was the best method to obtain the highest biosurfactant from the culture medium of the strain. The biosurfactant was confirmed as a mixture of mono and di-rhamnolipid congeners, Rha–C₁₀–C₁₀–CH₃ being the most abundant one. The biosurfactant was a good foaming and emulsifying agent.     

Mutation Breeding of Extracellular Polysaccharide-Producing Microalga Crypthecodinium cohnii by a Novel Mutagenesis with Atmospheric and Room Temperature Plasma

Extracellular polysaccharides (EPS) produced by marine microalgae have the potential to be used as antioxidants, antiviral agents, immunomodulators, and anti-inflammatory agents. Although the marine microalga Crypthecodinium cohnii releases EPS during the process of docosahexaenoic acid (DHA) production, the yield of EPS remains relatively low. To improve the EPS production, a novel mutagenesis of C. cohnii was conducted by atmospheric and room temperature plasma (ARTP). Of the 12 mutants obtained, 10 mutants exhibited significantly enhanced EPS yield on biomass as compared with the wild type strain. Among them, mutant M7 was the best as it could produce an EPS volumetric yield of 1.02 g/L, EPS yield on biomass of 0.39 g/g and EPS yield on glucose of 94 mg/g, which were 33.85%, 85.35% and 57.17% higher than that of the wild type strain, respectively. Results of the present study indicated that mutagenesis of the marine microalga C. cohnii by ARTP was highly effective leading to the high-yield production of EPS.     

Improvement of fermentative production of exopolysaccharides from Aureobasidium pullulans under various conditions

The optimization of exopolysaccharide (EPS) production was investigated in the polymorphic fungal strain of Aureobasidium pullulans (KCTC 6081) with varying pH, nutrients concentration, and mixing parameters in batch fermentation condition. The maximum production of EPS (～7.5 g/L) was observed at pH 4, while optimum nutrient concentration of carbon (sucrose), nitrogen (NaNO₃), phosphorous (K₂HPO₄), and ascorbic acid was 50 g/L, 5 g/L, 1 g/L and 2 g/L, respectively. Interestingly, EPS productivity under non pH controlled fermentation conditions was 0.12 g/L/h with 400 rpm mixing, while under a controlled pH of 4, the EPS productivity was 0.21 g/L/h with 600 rpm, respectively. The fed-batch fermentation increased the EPS productivity up to 0.345 g/L/h with changing mixing conditions from 200 to 600 rpm and reached 47 g/L with 88% pullulan. Thus, pH and mixing were the key parameters for enhancing EPS production from A. pullulans. It is expected that these optimized parameters can be well used for enhanced industrial production of pullulan.     

A study of mycelial growth and exopolysaccharide production from a submerged culture of <Emphasis Type="Italic">Mycoleptodonoides aitchisonii</Emphasis> in an air-lift bioreactor

We determined the optimal culture and medium conditions for effective production of mycelial mass and exopolysaccharide from a liquid culture of Mycoleptodonoides aitchisonii in an air-lift bioreactor. The mycelial growth and exopolysaccharide production were found to be optimal at a temperature of 25 °C and pH of 6.5. When 60 g/L of lactose was used as a carbon source, the maximum mycelial growth and exopolysaccharide production were obtained. The polypeptone and yeast extract were the most appropriate nitrogen sources for mycelial growth and exopolysaccharide production. In addition, when a mixture of 20 g/L of polypeptone and 5 g/L of yeast extract was used, the exopolysaccharide production increased 50% compared to that of the sole nitrogen source. CaCl₂·2H₂O (1.0 g/L) was the most effective mineral source. Using the optimal culture and medium conditions, batch cultures with basal and designed medium on mycelial growth and exopolysaccharide production in a 5 L air-lift bioreactor were carried out for 16 days. The mycelial growth and exopolysaccharide production increased with an increase of culture time at 14 days, and the maximum mycelial growth and exopolysaccharide production were 20.3 and 6.2 g/L, respectively, after 14 days of culture. The developed model in an air-lift bioreactor showed good agreement with experimental data. These results indicate that exopolysaccharide production is associated with the mycelial growth of M. aitchisonii in an air-lift bioreactor.     

Enhanced Bio-Ethanol Production from Industrial Potato Waste by Statistical Medium Optimization

Industrial wastes are of great interest as a substrate in production of value-added products to reduce cost, while managing the waste economically and environmentally. Bio-ethanol production from industrial wastes has gained attention because of its abundance, availability, and rich carbon and nitrogen content. In this study, industrial potato waste was used as a carbon source and a medium was optimized for ethanol production by using statistical designs. The effect of various medium components on ethanol production was evaluated. Yeast extract, malt extract, and MgSO₄·7H₂O showed significantly positive effects, whereas KH₂PO₄ and CaCl₂·2H₂O had a significantly negative effect (p-value < 0.05). Using response surface methodology, a medium consisting of 40.4 g/L (dry basis) industrial waste potato, 50 g/L malt extract, and 4.84 g/L MgSO₄·7H₂O was found optimal and yielded 24.6 g/L ethanol at 30 °C, 150 rpm, and 48 h of fermentation. In conclusion, this study demonstrated that industrial potato waste can be used effectively to enhance bioethanol production.     

Ammonium fumarate production by free or immobilised Rhizopus arrhizus in bench‐ and laboratory‐scale bioreactors

Ammonium fumarate production from glucose‐based media by Rhizopus arrhizus NRRL 1526 with mycelial growth controlled by phosphorus limitation exhibited mixed‐growth‐associated product formation kinetics, with growth‐associated production related to secondary mycelial growth only. The contribution of the primary mycelial growth phase was minimised by resorting to prolonged batch production using free mycelia under intermittent glucose feeding or repeated batch production using immobilised mycelia. The metabolic activity of free or immobilised mycelia was limited by fumarate accumulation or by oxygen diffusion phenomena, respectively. For batch cultures in a 15 dm³ stirred bioreactor the peripheral impeller speed (v_I) was increased from 1.88 to 3.3 m s^?1, and the fumarate yield coefficient on glucose increased from 0.25 ± 0.01 to 0.42 ± 0.02 g g^?1, while the malate yield coefficient on fumarate (Y_M/F) reduced from 0.46 ± 0.01 to 0.14 ± 0.01 g g^?1. With a net increase in the fumarate‐to‐malate ratio from 2 to 6.5, a v_I value of 3.3 m s^?1 gave the best fermentation performance and provided a basis for further scale‐up studies. © 2002 Society of Chemical Industry     

Production of l-asparaginase from Escherichia coli ATCC 11303: Optimization by response surface methodology

This paper discusses the studies carried out for the optimal production of enzyme l-asparaginase (l-asparagine amidohydrolase, EC 3.5.1.1) from Escherichia coli (ATCC 11303). It was found that inoculum age of 18 h and inoculum size of 10% were the most favorable operating conditions for enzyme production. Lactose, yeast extract and KH₂PO₄ were found to be the best carbon, nitrogen and ion sources, respectively. Statistical method was used to survey how various medium conditions affect the enzyme production. By response surface methodology, the values of lactose, tryptone, yeast extract, KH₂PO₄ and l-asparagine concentration were investigated to obtain the maximum enzyme activity. The highest enzyme activity, 1.03 U mL⁻¹ enzyme, was determined under the following conditions: 1.08% lactose, 1.79% tryptone, 1.6% yeast extract, 2% KH₂PO₄ and 0.19% l-asparagine. Response surface methodology proved to be a powerful tool in optimizing the medium and by this method, more than 10-fold (from 0.1 to 1.03 U mL⁻¹) enhancement in l-asparaginase activity was achieved as compared to that obtained in the basal medium (Luria-Bertani media, inoculum age of 24 h and inoculum size of 10%).     

Influence of Salt Concentration and Nitrogen Source on Growth and Productivity of Anaerobiosprillum succiniciproducens

The influence of salts and organic nitrogen sources on the growth and acid production of Anaerobiosprillum succiniciproducens was studied. In shake flask experiments, maximum specific growth rate and acid production increased by reducing the salt concentration. Additionally, growth and acid production were affected by the type of organic nitrogen source and by the pH value. Through the optimization, optical density could be increased from 1.9 ± 0.1 to 3.0 ± 0.1 and succinic acid concentration from 4.0 ± 0.2 to 6.5 ± 0.1 g L^–1. In fed‐batch experiments with the optimized medium, the final succinic acid concentration was 25.6 % higher compared to the reference. Also, the succinic acid/acetic acid ratio was affected by the optimization. The experimental results indicated that A. succiniciproducens consumed only organic nitrogen sources because growth and productivity were not influenced by the addition of ammonium sulfate.     

Use of Cottonseed Meal for Producing Eicosapentaenoic Acid by Pythium irregulare

Cottonseed meal (CSM), a common agricultural by‐product, was used as a nutrient source for the production of eicosapentaenoic acid (EPA) by Pythium irregulare. CSM can support good cell growth performance, as can yeast extract (YE). In terms of the maximum EPA content and EPA yield, CSM is superior to YE. Low concentrations of CSM are beneficial to lipid synthesis, and high concentrations favor the EPA content. Utilizing response surface methodology (RSM) analysis, the optimum contents of glucose and CSM in the fermentation medium were determined to be 40.2 and 16.1 g/l, respectively. After 6 days of fermentation at 25 °C and optimal conditions, the EPA yield and productivity were 245.3 and 40.9 mg/l day, respectively. Particle size of CSM was found to affect the EPA production, and a finely ground CSM (100 mesh) was determined to be best for EPA production. The variation in the fatty acid content of total fatty acid (TFA) indicates that EPA was synthesized through the n‐6 route in P. irregulare and Δ12 desaturase was the key enzyme for EPA biosynthesis. Sodium carbonate was determined to be notably good at removing free gossypol attached to biomass. After fungal biomass from each flask had been harvested from Na₂CO₃‐supplemented medium, 1 % (w/v) Na₂CO₃ solution was used to wash the mycelia three times; free gossypol (FG) was not detected (detection limit 0.0018 %). This work provides a new approach using cottonseed meal to produce EPA through fungal fermentation.     

Inhibition of Citrinin Production in Penicillium citrinum Cultures by Neem [Azadirachta indica A. Juss (Meliaceae)]

The efficacy of different concentrations of aqueous neem leaf extract (3.12 to 50 mg/mL) on growth and citrinin production in three isolates of Penicillium citrinum was investigated under laboratory conditions. Mycotoxin production by the isolates was suppressed, depending on the concentration of the plant extract added to culture media at the time of spore inoculation. Citrinin production in fungal mycelia grown for 21 days in culture media containing 3.12 mg/mL of the aqueous extract of neem leaf was inhibited by approximately 80% in three isolates of P. citrinum. High-performance liquid chromatography was performed to confirm the spectrophotometric results. Vegetative growth was assessed, but neem extract failed to inhibit it. Neem leaf extract showed inhibition of toxin production without retardation in fungal mycelia growth.     

Evolving Escherichia coli Host Strains for Efficient Deuterium Labeling of Recombinant Proteins Using Sodium Pyruvate-d3

Labeling of proteins with deuterium (2H) is often necessary for structural biology techniques, such as neutron crystallography, NMR spectroscopy, and small-angle neutron scattering. Perdeuteration in which all protium (1H) atoms are replaced by deuterium is a costly process. Typically, expression hosts are grown in a defined medium with heavy water as the solvent, which is supplemented with a deuterated carbon source. Escherichia coli, which is the most widely used host for recombinant protein production, can utilize several compounds as a carbon source. Glycerol-d₈ is often used as a carbon source for deuterium labelling due to its lower cost compered to glucose-d₇. In order to expand available options for recombinant protein deuteration, we investigated the possibility of producing a deuterated carbon source in-house. E. coli can utilize pyruvate as a carbon source and pyruvate-d₃ can be made by a relatively simple procedure. To circumvent the very poor growth of E. coli in minimal media with pyruvate as sole carbon source, adaptive laboratory evolution for strain improvement was applied. E. coli strains with enhanced growth in minimal pyruvate medium was subjected to whole genome sequencing and the genetic changes were revealed. One of the evolved strains was adapted for the widely used T7 RNA polymerase overexpression systems. Using the improved strain E. coli DAP1(DE3) and in-house produced deuterated carbon source (pyruvic acid-d₄ and sodium pyruvate-d₃), we produce deuterated (>90%) triose-phosphate isomerase, at quantities sufficient enough for large volume crystal production and subsequent analysis by neutron crystallography.     

Enhanced production of l(+)-lactic acid by floc-form culture of Rhizopus oryzae

A process to optimize l-lactic acid production from glucose by Rhizopus oryzae, based on sustaining floc morphology throughout the fermentation process, is herein performed. During the fermentation, supplementary ammonium sulfate was added intermittently to maintain the ammonia level of the culture medium always higher than 0.1 g/L. With replenish of nitrogen source, mycelia flocs did not aggregate, and the lactic acid production was optimized upon the fermentation being controlled at pH 4.3–4.5 by adding calcium carbonate slurry. In contrast, without supplementary addition of nitrogen source, mycelial clumps formed, resulting in a poor production of lactic acid. In the initial batch fermentation process, the final concentration of lactic acid produced was 109 g/L, with a yield (g lactic acid/g glucose consumed) of 0.87 and a productivity of 2.73 g/L h, using 125 g/L of glucose as substrate. For the first four cycles of repeated-batch fermentation, the average final concentration, the productivity and the yield of lactic acid were 113 g/L, 4.03 g/L h and 0.90, respectively.     

Fermentation strategy for the production of poly(3-hydroxyhexanoate) by <Emphasis Type="Italic">Aeromonas sp.</Emphasis> KC014

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P(3HB-co-3HHx)) was produced by Aeromonas sp. KC014 strain isolated from Taiwan in soil environment in the flask and fermentor cultures. The medium optimization, such as carbon source and nitrogen source, carbon-nitrogen ratio was conducted to obtain the optimum 3-hydroxyhexanoate content. The defined medium with dodecanoic acid as the carbon source and (NH₄)₂SO₄ as the nitrogen source was obtained as the main medium. When cells grown in medium containing 30 g/L dodecanoic acid, 15 g/L sodium gluconate and 1 g/L soytone (C/N was 30/1) as final PHA concentration, the cell dry weight and HB content of 5.16 g/L, 14.0 g/L and 36.0%, respectively, were obtained. The maximum HHx/PHA content increased from 0.1% to 1.3% nearly 12-fold when the dissolved oxygen was decreased from 40% to 20%. P(3HB-co-3HHx) biosynthesis was triggered by the addition of limited nitrogen, phosphorus and magnesium to get a maximum HHx/PHA content of 14% in 95 hours. This work was presented at 13 ^th YABEC symposium held at Seoul, Korea, October 20–22, 2007.     

Evaluation of a novel low-cost culture medium containing exclusively milk,potato and glycerol for microbial transglutaminase production by Streptomyces mobaraensis

The aim of this work was to evaluate the production of microbial transglutaminase (MTG) by Streptomyces mobaraensis in a reduced nutritional medium based on non-commercial potatoes. Initially, the production was studied comparing 3 culture media based on potato: (i) media based on acid hydrolysed potato, (ii) media based on gelified non-hydrolysed potato and (iii) media based on gelified non-hydrolysed potato supplemented with glucose (20 g/L). All media were supplemented with nutrients and inductors of MTG production (yeast extract, peptone, sodium caseinate, glycerol and mineral salts such as sodium phosphate, potassium phosphate, magnesium sulphate). The best medium was gelified non-hydrolysed potato allowed to obtain up to 2.72 U/mL at 96 h. In a second study, it was proposed the substitution of all the nutrients and inductors by exclusively skim milk and glycerol. An experimental design was performed to optimize the composition of milk, potato and glycerol. The economical yield of the process was also evaluated. Fermentations were carried out and samples were taken at 72 h and 96 h. Results showed that the maximum MTG activity was obtained at 72 h. A significant effect of potato and milk on MTG activity was observed, including an effect of interaction between both compounds. Optimal conditions selected were: 600 g/L of skim milk, 40 g/L of potato and 5 g/L of glycerol, yielding a maximum activity of 3.2 U/mL and an economic yield of 8.11 € of MTG/€ of nutrients. The results showed that the medium milk–potato–glycerol was feasible for the production of transglutaminase, obtaining a high MTG activity in a simple natural medium.     

Ceramide structure of sphingomyelin from human milk fat globule membrane

Sphingomyelin was purified from human milk fat globule membrane and submitted to phospholipase C to yield ceramide. The structure of this ceramide was investigated by gas liquid chromatographic analyses of its components, fatty acids and sphingoid bases. The structure of the native ceramide was confirmed by direct-inlet mass spectrometry. It was shown to contain a major base C₁₈-sphingosine associated with a high proportion (60%) of C₂₀, C₂₂, C₂₄ and C_24∶1 nonhydroxylated fatty acids. As these very long-chain fatty acids might be of nutritive importance, the concentration of sphingomyelin in human milk and its distribution in cream and skim milk were established.     

Effects of various carbon and nitrogen sources on fungal lipid production

The efficiency of lipid production byTolyposporium ehrenbergii andSpacelotheca reiliana (family Ustilaginaceae) cultivated on a fat-free medium was evaluated. The fungi were artificially cultured on media containing various monoor disaccharides and urea or peptone as basic sources for carbon and nitrogen, respectively. Some natural and industrial byproducts (glycerol, glucose syrup, potato hydrolysate and molasses hydrolysate) were also used as principal carbon sources for fungal growth. Media containing fructose/peptone or glucose/peptone were the most efficient for fungal fat production during one week of incubation. After a two-week incubation period, highest phospholipid concentrations were found in S.reiliana andT. ehrenbergii mycelia obtained from media containing molasses hydrolysate/peptone and glycerol/urea, respectively. Fatty acid analysis of the fungal growth indicated the presence of a wide range of fatty acids, i.e., odd-and even-carbon numbered acids, both saturated and unsaturated. The results demon-strated that the variability in the fatty acid composition largely depends on the type of sugar and nitrogen sources and the age of the culture.