Effect Of Various Nitrogen Sources Research Articles

Effects of Nitrogen Sources and Inorganic Salts on Antioxidant Activity of Goat Milk Fermented by Lactobacillus plantarum L60

Abstract This study investigated the effects of various nitrogen sources (peptone, casein hydrolysate) and inorganic salts (KH2PO4, MgSO4 and NaCl) on the antioxidant activity (specifically, DPPH and superoxide anion scavenging rate), acidity, and pH of peptides in goat milk (GM) fermented by Lactobacillus plantarum L60 by individual factor experiments. The results indicated that nitrogen sources and inorganic salts significantly affected L. plantarum L60’s antioxidant and acid-producing abilities, and when the supplemental levels of peptone, casein hydrolysate, KH2PO4, MgSO4 and NaCl were 0.7%, 0.3%, 0.3%, 0.15% and 0.9%, respectively, the scavenging ability of antioxidant peptides on DPPH radical and superoxide anion reached the maximum.

Effect of Varied Nitrogen Sources and Type of Cultivation on the Yield and Physicochemical Parameters of Flowering Chinese Cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee)

The aim of our study was to determine the effect of various nitrogen sources (NH4NO3 (N, 34%), Ca(NO3)2 (N, 15.5%; Ca, 18%), Mg(NO3)2 (N, 11%; Mg, 12%), NaNO3 (N, 15%; Na, 25%) and urea (N, 46%)) and increasing the intensity of N nutrition with these fertilisers (50, 70, and 90 mg N·dm−3) on the yield and quality of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee). The plants were grown in two different soilless systems, namely pot cultivation (substrate system—mixture of peat and sand) and hydroponic cultivation. The quality of plants was expressed as macro- and microelement contents, pigment contents, antioxidant activity and phenolic content. It was observed that the yield of flowering Chinese cabbage was about 43–70% higher in the hydroponic system than in the substrate. The N source and N nutrition affected the yield volume. The highest mean yield was observed in pot cultivation after fertilisation with Mg(NO3)2 and in hydroponics with Ca(NO3)2. We found a rather high tolerance of flowering cabbage to sodium and an excessive content of ammonium in the nutrient solution. The nitrogen source and N doses modified plant contents of macro- and microelements (N, P, K, Ca, Mg, Na, Fe, Mn, Zn and Cu) and other quality parameters of plants. In pot cultivation, the highest element contents as well as the highest antioxidant activity were obtained after fertilisation with Mg(NO3)2 at N-70 and N-90. The highest pigment contents (chlorophylls and carotenoids) were obtained in the samples treated with urea at the N-90 dose. Those samples were also characterised by a high Mn content. Generally, the pigment content in the pot system positively correlated with the Mn content in leaves, the microelement which is involved in the process of photosynthesis, but it did not correlate with colour coordinates. In the hydroponic system, the highest pigment contents were observed in the samples treated with Mg(NO3)2 at the N-70 dose. Generally, in hydroponics, chlorophyll levels positively correlated with Ca levels in the aboveground parts of the plants. Additionally, the content of Chl b inversely correlated with L* and b* values. In hydroponic systems, the highest DPPH (2,2-diphenyl-1-picrylhydrazyl) activity was observed after treatment with NH4NO3 at the N-70 and N-90 doses and it did not correlate with phenolic content but rather with pigment content. In conclusion, both the intensity of N nutrition and the fertiliser applied can significantly modify the yield of plants and their quality parameters. For pot cultivation, the most effective fertiliser was Mg(NO3)2 at the N-70/N-90 doses, while for hydroponic cultivation, it is difficult to indicate the most effective fertiliser as the responses varied depending on the method of fertilisation.

Effect of Various Nitrogen Sources at Various Sulfur Levels on Maize–Wheat Yield and N/S Uptake under Different Climatic Conditions

Effect of Various Nitrogen Sources at Various Sulfur Levels on Maize–Wheat Yield and N/S Uptake under Different Climatic Conditions

Effects of various nitrogen sources on some morpho-physiological characteristics of rosemary (Rosmarinus officinalis L.) under in vitro conditions

To investigate the effects of different nitrogen sources including ammonium nitrate, asparagine, and glutamine in five concentrations of 0, 50, 100,150, and 200 mg l-1 on some physiological and biochemical characteristics of rosemary (Rosmarinus officinalis L.), an experiment was conducted in a completely randomized design with five repliacations. The indices including plant height, shooting rate, number of leaves, necrotic leaf size, chlorophylls a, b, and total chlorophyll content, and the content of carotenoids, phenols, and flavonoids were measured. The results showed that the nitrogen sources significantly (P≤0.01) affected the all measured indices except the necrotic leaf size. The results of means comparison showed that the highest shooting rate and number of leaves were obtained at 100 mg l-1 of glutamine and asparagine and the highest plant height was obtained at 200 mg l-1 of ammonium nitrate. Also, the highest amount of photosynthetic pigments was obtained at 50 mg l-1 of asparagine and the highest amount of phenols and flavonoids was related to 200 mg l-1 of glutamine. In general, the results showed that the various nitrogen sources studied could positively and significantly improve the morphological and physiological characteristics of rosemary under in vitro conditions.

Effect of various nitrogen sources on yield, antioxidant activity and active substances of Crocus sativus L.

Effect of various nitrogen sources on yield, antioxidant activity and active substances of <i>Crocus sativus</i> L.

The effect of nitrogen source on in vitro growth of Neonectria ditissima (European canker)

Nitrogen fertilisers are widely used in apple orchards. However, the effects of various nitrogen sources on growth and sporulation of the fungus Neonectria ditissima, which causes European canker, are not fully understood. The effects of various nitrogen sources commonly used in apple orchards (potassium nitrate, ammonium chloride, ammonium nitrate, ammonium sulphate, Nitrophoska® and urea) on percent germination and germtube growth of N. ditissima conidia were tested in vitro. Nitrogen concentrations below 0.2 mol/L did not significantly affect percent conidial germination; however, concentrations above 0.2 mol/L significantly decreased germination. Germtube growth was also affected, generally decreasing with increased N. Percent germination was influenced by the N source, but germtube growth was not. Very low concentrations of urea were indicated to stimulate germtube growth. Higher concentrations, showed toxic effects on both germination and germtube growth. The presence of exogenous N from various sources did not affect initial germination and growth in the N. ditissima infection process of apple tissues.

Optimization of production conditions for xylanase production by newly isolated strain Aspergillus niger through solid state fermentation of oil palm empty fruit bunches

Abstract Response surface (RSM) optimization of selected cultural parameters and the effect of various nitrogen sources on xylanase production by novel strain of Aspergillus niger via solid state fermentation of oil-palm-empty-bunches (OPEFB) were assessed. The newly isolated oil-palm-field-domiciled strain of Aspergillus niger was identified based on rRNA analysis as Aspergillus niger USM SD2 (GenBank accession no. 2 ) value of 0.95. Xylanase activity was optimum at 25 °C, initial moisture-substrate ratio 4:1; pH 6.3 and total inoculums size, 2 × 10 6 spores/ml. At optimum production period, xylanase production was enhanced by more than 100% of its value prior optimization. Moreover, the use of yeast extract (Y/E) enhanced xylanase production better than any other nitrogen sources evaluated. Consequently, at its optimum concentration (15 g/l), the addition of Y/E enhanced xylanase production such that final activity (3246 IU/gds) was 160% and 29% higher than activities (1250 IU/gds) prior to and after (2512 IU/gds) parametric optimization respectively. Further analyses also showed that xylanase production by A. niger USM SD2 was independent of period of incubation and, hence, its growth rate.

Ethanol production via repeated-batch fermentation from carob pod extract by using Saccharomyces cerevisiae in biofilm reactor

In present study, repeated-batch fermentation in biofilm reactor was evaluated for ethanol production by using carob extract. Response surface method (RSM) was used to determine optimum initial sugar concentration, pH, and agitation in the constructed biofilm reactor. The optimum conditions for ethanol production in biofilm reactor were determined as initial sugar content of 7.71°Bx, pH of 5.18 and agitation of 120rpm. The ethanol production (P), the yield (YP/S) and production rate (QP) were found as 24.51g/L 48.59% and 2.14g/L/h at the optimized conditions, respectively. The fermentation time for maximum ethanol production in carob extract was reduced to 12h by using a biofilm reactor compared the published data in the literature, which was 30 and 24h by using suspended and immobilized yeasts in a stirred tank reactor, respectively. Furthermore, the effect of various nitrogen sources and enrichment were also evaluated and YP/S, QS and QP were significantly decreased compared to the results obtained from optimum conditions in biofilm reactor. Overall, results showed that a biofilm reactor for ethanol production from carob extract can be successfully implemented in point of reducing fermentation time, eliminate re-inoculation of the typical batch fermentation as well as increasing production yield.

Implication of Industrial Waste for Biomass and Lipid Production in Chlorella minutissima Under Autotrophic, Heterotrophic, and Mixotrophic Grown Conditions.

Following the diminishing hopes from the first and second generation biofuels, mainly due to the limitations of land availability, feed stock requirements, and complicated pre-treatments, third generation biofuels from microalgae are becoming a priority in the current scenario. The present study focuses on comparison and optimization of lipid accumulation efficiency in algal strain Chlorella minutissima grown under autotrophic, heterotrophic, and mixotrophic modes of nutrition, employing various carbon sources obtained from cheap industrial wastes such as glucose, acetate, and glycerol. Other pertinent factors such as the effect of various nitrogen sources, effect of salinity on the cell growth, and lipid accumulations in the algal cells were also studied. The results suggested that C. minutissima can grow efficiently under autotrophic, heterotrophic, and mixotrophic modes of nutrition. C. minutissima cells were capable of utilizing other non-popular carbon sources such as glycerol and acetate collected as waste products from different industries along with commonly used glucose. The maximum biomass concentration (8.9 g/L) and lipid content (36.19 %) were found in heterotrophic mode of nutrition. Our findings indicated that C. minutissima can efficiently utilize these cheaper carbon sources from industrial waste products for its growth and the production cost of various bioenergy sources can be reduced significantly.

Simplified feeding strategies for the fed-batch cultivation of Kluyveromyces lactis GG799 for enhanced recombinant xylanase production

A xylanase gene (xyn2) from Trichoderma reesei ATCC 58350 was previously cloned and expressed in Kluyveromyces lactis GG799. The production of the recombinant xylanase was conducted in a developed medium with an optimised batch and with fed-batches that were processed with glucose. The glucose served as a carbon source for cell growth and as an inducer for xylanase production. In a 1-L batch system, a glucose concentration of 20gL(-1) and 80% dissolved oxygen were found to provide the best conditions for the tested ranges. A xylanase activity of 75.53UmL(-1) was obtained. However, in the batch mode, glucose depletions reduced the synthesis of recombinant xylanase by K. lactis GG799. To maximise the production of xylanase, further optimisation was performed using exponential feeding. We investigated the effects of various nitrogen sources combined with the carbon to nitrogen (C/N) molar ratio on the production of xylanase. Of the various nitrogen sources, yeast extract was found to be the most useful for recombinant xylanase production. The highest xylanase production (110.13UmL(-1)) was measured at a C/N ratio of 50.08. These conditions led to a 45.8% increase in xylanase activity compared with the batch cultures. Interestingly, the further addition of 500gL(-1) glucose led to a 6.2-fold increase (465.07UmL(-1)) in recombinant xylanase activity. These findings, together with those of the exponential feeding strategy, indicate that the composition of the C/N molar ratio has a substantial impact on recombinant protein production in K. lactis.

Production of citrinin-free Monascus pigments by submerged culture at low pH

Microbial fermentation of citrinin-free Monascus pigments is of great interest to meet the demand of food safety. In the present work, the effect of various nitrogen sources, such as monosodium glutamate (MSG), cornmeal, (NH4)2SO4, and NaNO3, on Monascus fermentation was examined under different initial pH conditions. The composition of Monascus pigments and the final pH of fermentation broth after Monascus fermentation were determined. It was found that nitrogen source was directly related to the final pH and the final pH regulated the composition of Monascus pigments and the biosynthesis of citrinin. Thus, an ideal nitrogen source can be selected to control the final pH and then the citrinin biosynthesis. Citrinin-free orange pigments were produced at extremely low initial pH in the medium with (NH4)2SO4 or MSG as nitrogen source. No citrinin biosynthesis at extremely low pH was further confirmed by extractive fermentation of intracellular pigments in the nonionic surfactant Triton X-100 micelle aqueous solution. This is the first report about the production of citrinin-free Monascus pigments at extremely low pH.

Effects of nitrogen source on enhancing growth conditions of green algae to produce higher lipid

AbstractMicroalgae represent a potential source of biological material to produce biodiesel. This study focused on the effects of nitrogen concentration to enhance lipid content from Chlorella sorokiniana and their potential use to serve as a raw material for biofuel production. Light intensity and different nitrogen concentrations were used to determine the optimum cultivation environment for the fresh water microalgae, C. sorokiniana. The effects of various nitrogen sources were examined in order to determine the optimum lipid content produced by the microalgae. It was found that the optimum cultivation of microalgae growth has caused the biomass growth and has led to higher lipid production. The growth rate and lipid content were determined by measuring the optical density at 620 nm and fluorescence intensity using Nile red method. Microalgae of 10% (v/v) concentration was found to be the optimum inoculum concentration with higher growth rate obtained when compared to 50% (v/v). The nitrogen concentrat...

Micropropagule production from Trichoderma harzianum EGE-K38 using solid-state fermentation and a comparative study for drying methods

In this study, Trichoderma harzianum EGE-K38 was used for micropropagule production in solid-state fermentation. Various inexpensive agricultural co-products including wheat bran, sawdust, rice straw, hazelnut shell, grape marc, and cotton seed cake were tested as natural substrates, and zeolite was tested as an inert support for micropropagule production. Several parameters were determined to obtain maximum micropropagule production: the effects of various nitrogen sources, initial moisture content, initial pH, incubation temperature, and incubation time. Maximum micropropagule count achieved was (1.30 ± 0.68) × 10^{10} cfu/g dry substrate with a wheat bran-malt sprout mixture (3:2), at 28 °C, an initial moisture content of 70% (w/w), and an initial pH of 5.8 ± 0.3 after 4 days of cultivation. In zeolite-based medium, a maximum micropropagule count of (5.12 ± 0.61) × 10^8 cfu/g dry inert support was achieved. Optimized parameters were used in a higher scale where micropropagules were produced in trays using a wheat bran-malt sprout medium and harvested to determine the drying conditions in both lyophilization and oven-drying. It was found that up to 97% of micropropagules retained their viability with glycerol as a protectant after 1 day of oven-drying at 40 °C.

Comparison of three Yarrowia lipolytica strains for lipase production: NBRC 1658, IFO 1195, and a local strain

Lipase production was examined with 3 strains of Yarrowia lipolytica: NBRC 1658, IFO 1195, and a local strain. All strains were obtained from Hacettepe University's Department of Food Engineering. The addition of nitrogen and carbon sources and the effects of initial pH and temperature parameters were studied. For all 3 strains, the growth temperature range was 20-40 °C, and maximum growth was determined at 30 °C. The initial pH range was 6-9 for growth and 3-6 for lipase production. Maximum growth results were detected as follows: Y. lipolytica NBRC 1658 at 30 °C and pH 8, Y. lipolytica IFO 1195 at 30 °C and pH 8-9, and Y. lipolytica local strain at 30 °C and pH 7. However, maximum lipase production was detected at 30 °C and pH 4.4 for Y. lipolytica NBRC 1658, at 30 °C and pH 4.8 for Y. lipolytica IFO 1195, and at 30 °C and pH 4.6 for Y. lipolytica local strain. The effects of various nitrogen sources on lipase production showed that ammonium sulfate increased the lipase production, whereas urea, peptone, and casein did not show a distinct effect on lipase production. The addition of various sugars also did not increase lipase production efficiently. However, some oils showed a distinct effect on lipase production. The highest lipase activity determined was 16 U/mL, with the addition of 1% ammonium sulfate and 1% olive oil into the production medium of Y. lipolytica NBRC 1658.

Effects of nitrogen specification and culture method on growth of Enteromorpha prolifera

Eutrophication, which is the enrichment of a water mass with inorganic and organic nutrients that support plant growth, is a key factor in stimulating phytoplankton growth. In this study, we determined the effects of various nitrogen sources, different nitrogen concentrations in the culture medium, and two culture methods on the growth of the green alga, Enteromorpha prolifera. The relationship between the specific growth rate of E. prolifera and NO (3) (-) -N concentration was consistent with that estimated using the Monod equation (R (2) = 0.9713, P < 0.01). In the NO (3) (-) -N medium, the maximum specific growth rate was calculated to be 0.1634/d and the semi-saturation constant was calculated to be 16.86 mu mol/L. Our results show that E. prolifera can effectively utilize NH (4) (+) -N, NO (3) (-) -N, and NO (2) (-) -N and urea-N in the range of 5 to 50 mu mol/L. NH (4) (+) -N was preferentially assimilated by E. prolifera, and urea-N was favorable for long-term growth.

Effect of nutritional conditions on extracellular protease production by the haloalkaliphilic archaeon Natrialba magadii

The effect of various nitrogen sources and nutritional starvation was examined on the production of an extracellular protease secreted by the haloalkaliphilic archaeon Natrialba magadii. Cell growth and proteolytic activity were measured in cells grown with different nitrogen sources. Proteolytic activity was produced in complex and easily metabolized nitrogen sources such as yeast extract, casein and casamino acids; meanwhile, ammonium repressed enzyme production. The time course and amount of protease accumulated showed an inverse correlation with growth rate and nutrient concentration. Starvation did not induce extracellular protease production. The accumulation of Nab. magadii extracellular protease is stimulated by nutrient limitation and slow growth rate indicating that it is probably induced in response to a deficit in the energetic status of the cells. Nutritional starvation did not induce protease accumulation suggesting that de novo synthesis of this protease and/or factor/s necessary for its activation are required. This enzyme may be regulated by nitrogen catabolite repression and it does not require protein substrates for induction. These results contribute to the basic knowledge on protease regulation in haloalkaliphilic archaea and will help to optimize the production of this extremozyme for biotechnological applications such as protease-catalysed peptide synthesis.

Production of Aspergillus niger Biomass from Rice Bran

Growth of Aspergillus niger on rice bran medium in submerged fermentation was studied using standard methods for determinations of dry biomass, total crude protein and final pH values. It was observed that A. niger biomass cropped on rice bran medium supplemented with glucose, (NH ) SO , KH PO , 4 2 4 2 4 MgSO .7H O and ZnSO .7H O designated as Glucose supplemented rice bran (GRB) medium was highest 4 2 4 2 at 2.03±0.02g/l while the unsupplemented rice bran medium (RBM) has the lowest value of 0.97±0.00g/l. The effect of various nitrogen sources on the final biomass yield was compared. Ammonium sulphate [(NH ) 4 2 SO ] gave the highest biomass yield of 1.95±0.03g/l and sodium nitrate (NaNO ) had the lowest yield of 4 3 0.97±0.02g/l. Glucose and nitrogen supplements increased biomass yield.

Effect of nitrogen limitation and nature of the feed upon Oenococcus oeni metabolism and extracellular protein production

The aim of the study was to characterize the effect of various nitrogen sources on Oenococcus oeni growth, carbon source utilization, extracellular protease activity and extracellular proteins. More generally, the goal is to understand how nitrogen-based additives might act to enhance malolactic fermentation in wine. Five yeast extracts were used. As the amino acid and nitrogen analyses revealed, they were similar in global amino acid composition, except for arginine level. Nevertheless the ratio of amino acids between free/bound, and low/high molecular weight fractions were highly different. One of the yeast extracts led to a significant protease activity in the supernatant and to a poor final biomass of the IOB84.13 strain compared to the other ones. For the IOB84.13 strain specifically, arginine addition to the arginine poor yeast extract did not restore growth. 35S-methionine-labelled extracellular proteins were separated by SDS-PAGE. Signals were detected in all media early in the growth phase and were maintained during 48 h of culture. A significant protease activity was detected for O. oeni supernatants during growth under nitrogen limitation but only for certain nitrogen sources. Moreover, the activity was strain dependent. Peptides (0.5-10 kDa) seemed to be more favourable for growth of wine bacteria than <0.5 kDa nitrogen sources. The extracellular protein signal patterns differed more greatly between the bacterial strains tested than between the nitrogen molecules in the medium. This is the first study extensively considering the role of the nitrogen source composition and level upon O. oeni growth and metabolism.

Lactic acid production through cell-recycle repeated-batch bioreactor.

The effect of various nitrogen sources on cell growth and lactic acid production was investigated. The most effective nitrogen source was yeast extract; more yeast extract gave higher cell growth and lactic acid productivity. Yeast extract dosage and cell growth were proportional up to a yeast extract concentration of 30 g/L, and lactic acid productivity was linearly correlated up to a yeast extract dosage of 25 g/L. However, increasing the yeast extract content raises the total production cost of lactic acid. Therefore, we attempted to find the optimum yeast extract dosage for a repeated-batch operation with cell recycling. The results show that when using Enterococcus faecalis RKY1 only 26% of the yeast extract dosage for a conventional batch fermentation was sufficient to produce the same amount of lactic acid, whereas the lactic acid concentration in the product stream (92-94 g/L) and lactic acid productivity (6.03-6.20 g/[L x h]) were similar to those of a batch operation. Furthermore, long-term stability was established.

Giuconacetobacter persimmonus KJ145를 이용한 Bacterial Cellulose 생산조건

Gluconacetobacter persimmonus KJ145를 사용하여 bacterial cellulose 생산에 최적배지와 배양조건을 설정하였다. Bacterial cellulose를 생성하기 위한 최적배지로는 HS배지보다는 천연사과과즙이 더 우수한 경향을 나타내었으며, 사과과즙에 각종 탄소원을 보강한 결과 탄소원으로 pyruvate가 적합하였다. 탄소원의 농도를 조사한 결과, 1%가 적합하였으며, 각종 질소원의 영향을 조사한 결과 CSL이 가장 우수한 결과를 나타내었다. CSL의 농도에 따른 bacterial cellulose의 생산성을 조사한 결과, 10% 농도에서 가장 좋았다. Bacterial cellulose의 생성에 미치는 배지의 초기 pH의 영향을 조사한 결과 pH 6.0에서 최적이었으며, 배양온도별 영향을 조사한 결과 35o℃에서 하는 것이 최적이었다. 최적배양조건에서 배양시간별로 생성되는 bacterial cellulose의 양을 조사한 결과 16일간 배양하는 것이 가장 좋았으며, 이 때 생성되는 bacterial cellulose의 생산량은 8.96 g/L으로 비교적 높았다.