Enhancing fucoxanthin production in Phaeodactylum tricornutum by photo-fermentation / 生物工程学报

The aim of this study was to develop a technical system for high-efficient production of fucoxanthin by photo-fermentation of Phaeodactylum tricornutum. In a 5 L photo-fermentation tank, the effects of initial light intensity, nitrogen source and concentration as well as light quality on biomass concentration and fucoxanthin accumulation in P. tricornutum were investigated systematically under mixotrophic condition. The results showed that the biomass concentration, fucoxanthin content and productivity reached the highest level of 3.80 g/L, 13.44 mg/g and 4.70 mg/(L·d) under the optimal conditions of initial light intensity of 100 μmol/(m2·s), 0.02 mol TN/L of tryptone: urea (1:1, N mol/N mol) as mixed nitrogen source, and a mixed red/blue (R: B=6:1) light, 1.41, 1.33 and 2.05-fold higher than that before optimization, respectively. This study developed a key technology for enhancing the production of fucoxanthin by photo-fermentation of P. tricornutum, facilitating the development of marine natural products.

Growth and proximate composition of Pleurotus ostreatuscultivated on green bocaiuva pulp substrates with different nitrogen sources

The aim of this work was to evaluate the growth and the proximate compositionof the mycelium-based bocaiuva pulp with the edible mushroom Pleurotusostreatuson green bocaiuva flour added with different sources of nitrogen (urea, ammonium nitrate and sulfate ammonia). Growth was monitored by kinectics. At the end, the proximate composition of the best three treatments (dehydrated green bocaiuva pulp and water, T1; dehydrated green bocaiuva pulp and ammonium nitrate, T3; and green bocaiuva pulp/wheat bran and ammonium nitrate, T7) was determined. Ammonium nitrate was the nitrogen source that showed the greatest growth in both substrates (T3:8.33 cm and T7:7.67 cm) in relation to the other treatments (4.67 to 7.17 cm), with emphasis on the green bocaiuva pulp. The substrate with green bocaiuva pulp and water was the one that showed the highest growth (7.50 cm), which was close to the treatment with mixed substrate and ammonium nitrate (7.67 cm). The treatment with the green bocaiuva pulp and ammonium nitrate (T3) was highlighted due to its significant increase in proteins (9.42 g 100 g-1) and fibers (5.21 g 100 g-1), and decrease in carbohydrates (9.52 g 100 g-1), in comparison to the other treatments T7 (8.94, 2.16, and 5.99 g 100 g-1, respectively) and T1 (2.78, 4.33, and 2.28 g 100 g-1, respectively). The product obtained from the growth of P. ostreatusin green bocaiuva pulp presents promising perspectives to be utilized as raw material for the development of new food products with added nutritional value.

Enhanced production of prodigiosin by Serratia marcescens FZSF02 in the form of pigment pellets

Background: Prodigiosin has been demonstrated to be an important candidate in investigating anticancer drugs and in many other applications in recent years. However, industrial production of prodigiosin has not been achieved. In this study, we found a prodigiosin-producing strain, Serratia marcescens FZSF02, and its fermentation strategies were studied to achieve the maximum yield of prodigiosin. Results: When the culture medium consisted of 16.97 g/L of peanut powder, 16.02 g/L of beef extract, and 11.29 mL/L of olive oil, prodigiosin reached a yield of 13.622 ± 236 mg/L after culturing at 26 °C for 72 h. Furthermore, when 10 mL/L olive oil was added to the fermentation broth at the 24th hour of fermentation, the maximum prodigiosin production of 15,420.9 mg/L was obtained, which was 9.3-fold higher than the initial level before medium optimization. More than 60% of the prodigiosin produced with this optimized fermentation strategy was in the form of pigment pellets. To the best of our knowledge, this is the first report on this phenomenon of pigment pellet formation, which made it much easier to extract prodigiosin at low cost. Prodigiosin was then purified and identified by absorption spectroscopy, HPLC, and LCMS. Purified prodigiosin obtained in this study showed anticancer activity in separate experiments on several human cell cultures: A549, K562, HL60, HepG2, and HCT116. Conclusions: This is a promising strain for producing prodigiosin. The prodigiosin has potential in anticancer medicine studies.

Alanine mother liquor as a nitrogen source for docosahexaenoic acid production by Schizochytrium sp. B4D1

Alanine mother liquor, a type of industrial waste from alanine fermentation, was used as a nitrogen source to produce docosahexaenoic acid (DHA) by Schizochytrium sp. B4D1. The results indicated that yeast extract could trigger the utilization of the alanine mother liquor. Additionally, the alanine can be quenched during the culture, which aids in DHA accumulation. The medium components were optimized via response surface methodology as follows: 99.98-g/L glucose, 0.05-g/L yeast extract and a 183.17 dilution factor of the alanine mother liquid (v/v, with an alanine content of 0.72 g/L) and 17.98% inoculum concentration (v/v). Finally, in a 50-mL shake-flask fermentation, the DHA yield was 2.29 g/L.

The effect of Hydropolymers on soil microbial activities in Mediterranean areas / El efecto de los polímeros absorbentes en la actividad microbiológica del suelo bajo condiciones mediterráneas

ABSTRACT Objectives. The aim of this study was to evaluate the effect of the hydropolymer TerraCottem on soil microbial activity by measuring soil respiration and leaching of mineral nitrogen. Materials and methods. The incubation experiment contained control variants with natural soil of Nerja area (South Spain, inside the Sierra Tejeda, Almijara and Alhama Natural Park, 36.7985173° N 3.8511693° W; WCGS84), variants with the addition of easy available nitrogen compounds (kg N ha-1), easy accessible carbon compounds (1% glucose solution) and a combinations of both. Within each variant, the recommended amount of control hydropolymers (1.5 kg/m3) and a double dose of 3.0 kg/m3 were compared. Results. Showed that respiration activity of the soil in this Mediterranean area was not eliminated by the lack of ready available nitrogen or carbon substrates. Furthermore, differences in CO2 production between the variants containing different amounts of hydropolymers were not significant. A statistically significant difference in the CO2 production was found in the first week compared to longer time periods. Conclusions. The mineral nitrogen leaching measurement showed that the biological activity of the studied is not affected by nitrogen dynamics which is balanced regardless of the amount of applied hydropolymer. On the other hand, leaching processes occurred when soil was doped only with nitrogen compounds or only carbonaceous, a problem that can appear after fertilizers application.

RESUMEN Objetivo. El objetivo de este estudio pasa por evaluar el efecto del-Terracottem- en la actividad microbiana del suelo mediante la medida de la respiración edáfica y la pérdida de nitrógeno mineral por lixiviación. El ensayo se ha realizado en condiciones de laboratorio controladas y con suelos naturales. Materiales y métodos. Para el experimento, se han diseñado varios tratamientos: i) suelos naturales a los que se les ha adicionado compuestos nitrogenados de libre disponibilidad (Kg N ha-1); ii) suelos naturales a los que se les ha adicionado carbohidratos de libre disponibilidad (1% de solución de glucosa); iii) suelos naturales a los que se les ha adicionado una mezcla de compuestos nitrogenados de libre disponibilidad (Kg N ha-1) con carbohidratos (1% de solución de glucosa). En cada variante se han testeado diferentes dosis del polímero. Resultados. Los resultados han demostrado que la actividad respiratoria del suelo es independiente de la disponibilidad de compuestos como el nitrógeno o carbono. Tampoco se han observado diferencias significativas entre las diferentes dosis del polímero. Por el contrario, si se observaron diferencias en la producción de CO2. Conclusiones. La lixiviación únicamente se producía cuando los suelos eran enmendados con compuestos únicamente nitrogenados o únicamente sólo carbonosos.

Putative 3-nitrotyrosine detoxifying genes identified in the yeast Debaryomyces hansenii: in silico search of regulatory sequences responsive to salt and nitrogen stress

Background: During salt stress, the yeast Debaryomyces hansenii synthesizes tyrosine as a strategy to avoid the oxidation of proteins. Tyrosine reacts with nitrogen radicals to form 3-nitrotyrosine. 3-nitrotyrosine prevents the effects of associated oxidative stress and thus contributes to the high halotolerace of the yeast. However, the mechanism of how D. hansenii counteracts the presence of this toxic compound is unclear. In this work, we evaluated D. hansenii's capacity to assimilate 3-nitrotyrosine as a unique nitrogen source and measured its denitrase activity under salt stress. To identify putative genes related to the assimilation of 3-nitrotyrosine, we performed an in silico search in the promoter regions of D. hansenii genome. Results: We identified 15 genes whose promoters had binding site sequences for transcriptional factors of sodium, nitrogen, and oxidative stress with oxidoreductase and monooxygenase GO annotations. Two of these genes, DEHA2E24178g and DEHA2C00286g, coding for putative denitrases and having GATA sequences, were evaluated by RT-PCR and showed high expression under salt and nitrogen stress. Conclusions: D. hansenii can grow in the presence of 3-nitrotyrosine as the only nitrogen source and has a high specific denitrase activity to degrade 3-nitrotyrosine in 1 and 2 M NaCl stress conditions. The results suggest that given the lack of information on transcriptional factors in D. hansenii, the genes identified in our in silico analysis may help explain 3-nitrotyrosine assimilation mechanisms.

Production of docosahexaenoic acid by Aurantiochytrium sp. ATCC PRA-276

Abstract The high costs and environmental concerns associated with using marine resources as sources of oils rich in polyunsaturated fatty acids have prompted searches for alternative sources of such oils. Some microorganisms, among them members of the genus Aurantiochytrium, can synthesize large amounts of these biocompounds. However, various parameters that affect the polyunsaturated fatty acids production of these organisms, such as the carbon and nitrogen sources supplied during their cultivation, require further elucidation. The objective of this investigation was to study the effect of different concentrations of carbon and total nitrogen on the production of polyunsaturated fatty acids, particularly docosahexaenoic acid, by Aurantiochytrium sp. ATCC PRA-276. We performed batch system experiments using an initial glucose concentration of 30 g/L and three different concentrations of total nitrogen, including 3.0, 0.44, and 0.22 g/L, and fed-batch system experiments in which 0.14 g/L of glucose and 0.0014 g/L of total nitrogen were supplied hourly. To assess the effects of these different treatments, we determined the biomass, glucose, total nitrogen and polyunsaturated fatty acids concentration. The maximum cell concentration (23.9 g/L) was obtained after 96 h of cultivation in the batch system using initial concentrations of 0.22 g/L total nitrogen and 30 g/L glucose. Under these conditions, we observed the highest level of polyunsaturated fatty acids production (3.6 g/L), with docosahexaenoic acid and docosapentaenoic acid ω6 concentrations reaching 2.54 and 0.80 g/L, respectively.

Citric acid production by Aspergillus niger using different substrates

Aims: Citric acid is a commercially important acid that has many applications in varying sectors of industries. It is produced by various substrates through solid state or submerged fermentation. The capabilities of potato and rice as substrates for citric acid production using Aspergillus niger were tested in this experiment under submerged fermentation. Methodology and results: Potato and rice extract media were prepared and inoculated with A. niger and titrations were carried out to determine the amount of citric acid produced. It was shown that rice extract media proved more useful than potato extract media as it produced the highest citric acid production. Rice extract media was supplemented with varying concentrations of glucose and sucrose and 5% sucrose (w/v) proved to be the best as it produced the highest amount of citric acid. The rice extract media with 5% sucrose (w/v) were supplemented with varying concentrations of ammonium nitrate and ammonium sulphate and 0.25% ammonium nitrate proved more effective in citric acid production. A low pH (1.9-2.3) was found during the maximum production of citric acid. Conclusion, significance and impact of study: The results depict that potato and rice extract media can produce citric acid, hence providing an alternate substrate for citric acid production.

Keratinolytic Protease Production and Characterization from Bacillus Sp. Isolated from Poultry Wastes.

Keratinases originating from microorganisms are used in many industrial fields such as the recycle of keratinous wastes, leather, textile, the detergent industry and medical applications. In this study, 42 Bacillus strain were isolated from Cukurova University Research and Application and Chicken Management Unit. 8 of these isolates showed proteolytic activity on skim-milk and keratinolytic activity with keratin-azure on the basal feather-meal medium. Strain H62 with the highest keratinase activity was determined as the keratinase producer and identified as Bacillus licheniformis with microscopic, biochemical (VITEK-2, 90%) and molecular analysis (16S rRNA, 99%, B. licheniformis 9945A). The highest enzyme production was carried out at 40°C for 45 hours by adding 0.1 g/l mannitol (as carbon source), 0.1 g/l ammonium nitrate (as nitrogen source) and 15 g/l feathermeal into the basal feather-meal medium. Although keratinase showed the activity at 20-90°C and pH 5.0-13.0, optimum activity was obtained at 40°C and pH 9.5. 100% of stability was determined at pH 8.0, whereas the loss of activity was observed at pH 7.0-9.0. After a pre-incubation at 20-100°C enzyme was 100% stable whereas activity was decreased at the other temperatures. At room temperature, a loss of activity was determined after the 24th hour. EDTA, SDS and Urea increased the enzyme activity; however, Tween-20 was decreased. The enzyme was seen to be a single band with a molecular weight of 26 kDa. As a result, keratinase B. Licheniformis H62 is an enzyme that can be used in mesophyll and alkaline conditions, particularly in medical applications and as feed supplements.

Effects of physicochemical factors and cultivation substrates on mycelial growth in Omphalia lapidescens / 中草药

Objective: To confirm the influential factors on mycelial growth of Omphalia lapidescens and to provide a basis for the artificial cultivation. Methods: The mycelial growth rates of O. lapidescens under different culture conditions were measured. Results: With the temperature of 25 ℃ and pH 6.0-7.0, the mycelium of O. lapidescens was in its rapid growth. And there was no significant difference in mycelial growth rate with the concentration of carbon sources between 1% and 3%. Nitrogen sources such as peptone and yeast powder inhibited the mycelial growth, while the corn flour was not inhibited. The more suitable ingredient for the cultivation of O. lapidescens was bamboo leaves, meanwhile the growth-promoting effect of corn flour was obvious. Conclusion: The effects of temperature, nitrogen source, and matrix on mycelial growth of O. lapidescens are significant.

Raman Spectral Profiles of Promoting Effects of Organic Nitrogen Sources on Ethanol Fermentation Using Saccharomyces cerevisiae / 分析化学

Nitrogen is an essential nutrient for yeast cells on ethanol fermentation. In order to reveal the promoting mechanisms of organic nitrogen sources on the ethanol fermentation by yeast, Saccharomyces cerevisiae, laser tweezers Raman spectroscopy and single-cell analysis techniques were used to monitored the kinetic of intracellular bio-macromolecules of individual cells during fermentation with urea, yeast extract, ammonium nitrate or ammonium sulfate as the sole nitrogen source. Major results from this work were as follows. (1) Organic nitrogen sources had a promoting effect on the ethanol fermentation, the fermentation with urea and yeast extract reached the maximum concentration of ethanol in 14-18 h. ( 2 ) There were no apparent lag phases for the RNA synthesis of yeast cells cultured with urea and yeast extract. The averaged Raman intensity of yeast cells at peak of 782 cm-1 in the early stage of fermentation was stronger than that of cultured with ammonium nitrate and ammonium sulfate. The maximum was about 1. 9-2. 1 times of the initial intensity for urea or yeast extract, but 1. 2-1. 4 times for ammonium nitrate and ammonium sulfate. (3) The secondary structure of proteins of partial cells cultured with yeast extract was dominated byβ-sheet, while cells cultured with other nitrogen sources were dominated by α-helix absolutely. These results bring us the conclusion that the improving effect of organic nitrogen sources such as urea and yeast extract on ethanol fermentation by Saccharomyces cerevisiae may be due to that the organic nitrogen sources can shorten the lag phase of yeast cells, promote the RNA synthesis, and promote the transcription and expression of related genes.

Screening of Locally Isolated Aspergillus species for Their Cellulolytic Potential and Their Optimization on Vigna mungo in Solid State Fermentation.

Aims: To evaluate cellulolytic potential of locally isolated Aspergillus species and emphasis the importance of screening on qualitative bases. Also, to enhance cellulase production by optimizing the process parameters of the solid state fermentation of Vigna mungo with the isolated Aspergillus species. Place and Duration of Study: Institute of Biological Sciences, Department of Botany, University of Gujrat, Gujrat, Pakistan, from February, 2012 to November, 2012. Methodology: Aspergillus species were isolated from different deteriorated plant materials and maintained on potato dextrose agar. The purified isolated species were qualitatively screened on caboxymethylcellulose agar plates. The cellulolytic ability was further tested by culturing Aspergillus species on V. mungo in solid state fermentation. Various nutritional and cultivation parameters were optimized for the production of cellulases by Aspergillus species on V. mungo. Results: Most of the isolated Aspergillus species showed potential for cellulase production. However, A. terreus gave qualitatively, the highest cellulase activity by fermenting V. mungo of 0.566 IU/g while A. niger gave quantitatively, the highest cellulase activity of 0.435 IU/g. Cellulase production by A. terreus reached at its maximum with 0.1% of urea as nitrogen source and 80% of initial moisture level at 35°C after 144 hours of fermentation. Conclusion: A. terreus was identified as highest cellulase producer among the isolated Aspergillus species. The cellulolytic ability of Aspergillus specie greatly depends upon the nutritional and cultivation parameters of fermentation.

Effect of nitrogen sources on the production of invertase by yeast saccharomyces cerevisiae 3090.

Invertase from Saccharomyces cerevisiae is high cost enzyme and primarily used in the confectionary industry. For large scale production of the enzyme, feasible synthetic medium with appropriate supplemented nutrients are required. The effect of carbon source on invertase production is well known, but little is known about the effect of different nitrogen source. The aim of the present study is to see the effect of different nitrogen sources on the production of invertase in submerged fermentation by Saccharomyces cerevisiae. It was found that when urea as nitrogen source is added in a little amount to the fermentation medium it showed a marked increase in Invertase production.

Improvement of Growth and Periplocin Yield of Periploca sepium Adventitious Root Cultures by Altering Nitrogen Source Supply / 中草药·英文版

Objective To increase the ultimate yield of periplocin in Periploca sepium adventitious root cultures by a two-stage culture based on nitrogen source.Methods Firstly,the effects of nitrogen source(NH-NO-)at different ratios and different total initial nitrogen amounts on the accumulation of biomass and secondary metabolites in adventitious root cultures of P sepium were investigated,and growth and production media for the two-stage culture based on the above results were established.Results The highest biomass and periplocin content were obtained in the culture medium of 15 mmol/L total nitrogen amount with NH-NO(1:2)and 30 mmol/L total nitrogen amount with nitrate as the sole nitrogen source.By adopting a fed-batch cultivation strategy,the dry weight adventitious root,periplocin content and yield were increased by 136%,108%,and 389%,respectively when compared with those of the control,reaching up to 8.13 g/L,157.15 μg/g,and 1277.63 μg/L,respectively.Furthermore,it was found that in the process of two-stage culture,the adventitious roots grew thicker significantly after they were transferred into production medium directly.Conclusion The ultimate yield of periplocin in P.sepium adventitious root cultures could be significantly increased by a two-stage culture based on nitrogen source.

Cultural Characteristics of Ophiocordyceps heteropoda Collected from Korea

Isolates of Ophiocordyceps heteropoda (Kobayasi) collected from Mt. Halla on Jeju-do, Korea were tested for mycelial growth on different agar media and in the presence of different carbon and nitrogen sources. Similarly, isolates were also incubated at different temperatures as well as under continuous light and dark conditions. Growth was better on Hamada agar, basal medium, and malt-yeast agar, but poor on Czapek-Dox agar. Different carbon sources such as dextrin, saccharose, starch, lactose, maltose, fructose, and dextrose resulted in better growth. Complex organic nitrogen sources such as yeast extract and peptone revealed the most effective growth. Mycelial growth was best at 25degrees C. The growth rate was faster in the dark than the light, but mycelial density was less compact in the dark.

Growth and Cultural Characteristics of Ophiocordyceps longissima Collected in Korea

We investigated the effect of nutritional and environmental factors on Ophiocordyceps longissima mycelial growth. The longest colony diameter was observed on Schizophyllum (mushroom) genetics complete medium plus yeast extract, Schizophyllum (mushroom) genetics minimal medium, and Sabouraud dextrose agar (SDA); however, malt-extract yeast-extract agar, SDA plus yeast extract, yeast-extract malt-extract peptone dextrose agar, SDA, oatmeal agar, and potato dextrose agar showed higher mycelia density. A temperature of 25degrees C was optimum and 7.0 was the optimum pH for mycelial growth. Colony diameter was similar under light and dark conditions. Maltose and yeast extract showed the highest mycelial growth among carbon and nitrogen sources respectively. The effect of mineral salts was less obvious; however, K3PO4 showed slightly better growth than that of the other mineral salts tested. Among all nutrition sources tested, complex organic nitrogen sources such as yeast extract, peptone, and tryptone were best for mycelial growth of O. longissima. Ophiocordyceps longissima composite medium, formulated by adding maltose (2% w/v), yeast extract (1% w/v), and K3PO4 (0.05% w/v) resulted in slightly longer colony diameter. In vitro mycelial O. longissima growth was sustainable and the production of fruiting bodies could be used for commercial purposes in the future.

Characteristics of Metacordyceps yongmunensis, a New Species from Korea

Metacordyceps yongmunensis is a newly reported species from Korea, which is very similar to Cordyceps species in morphological characters. It grows on large lepidopteran pupa, and numerous white stromata grow on a single host. Mycelial growth characteristics of M. yongmunensis isolates were studied in different media and at different temperatures. Also, different carbon sources, nitrogen sources, and mineral salts were tested for mycelial growth of M. yongmunensis. Schizophyllum (mushroom) genetics complete medium plus yeast extract, Schizophyllum (mushroom) genetics minimal medium, and Martin's peptone dextrose agar produced longer colony diameters and more compact mycelial density than other media. The optimum temperature for mycelial growth was 25degrees C. Carbon sources such as sucrose, soluble starch, dextrose, glucose, dextrin, maltose, and fructose showed better mycelial growth, whereas peptone, yeast extract and tryptone resulted in the best mycelial growth of all of the nitrogen sources tested. All of the mineral salts tested showed similar growth as the control, except K2HPO4 which showed longer colony diameter and more compact mycelial density. The compact colonies were white and cottony with a greenish margin. The results showed that M. yongmunensis is an easy fungus to growas it grew from 30 to more than 50 mm in 2 wk.

Studies on the Effects of Different Carbon Sources and Nitrogen Sources on the Growth of Phellinus Nigricans / 微生物学通报

The effects of four kinds of carbon sources and nine kinds of nitrogen sources on the fungus Phellinus nigricans mycelia were studied.The four kinds of carbon source are sucrose,lactose,glucose,soluble starch.The nine kinds of nitrogen source are corn meal,wheat bran,potato,soybean meal,yeast extract powder,peptone,potassium nitrate,ammonium nitrate,and urea.Polysaccharides were extracted from different generations of mycelia and the contents,monosaccharide components and molecular weight were analyzed.The results were that the optical carbon source and nitrogen source were starch and corn meal.The optical combination was sucrose and corn meal.The properties of polysaccharides from different generations of mycelia were stable.