Optimal Glucose Concentration Research Articles

Enhanced phenylpyruvic acid production with Proteus vulgaris by optimizing of the fermentation medium

Alpha keto acids are important food additives, which commonly produced by microbial deamination of amino acids. In this study, production of phenylpyruvic acid (PPA), which is the alpha keto acid of phenylalanine was enhanced in 2-l bench scale bioreactors by optimizing of fermentation medium composition using the Box-Behnken Response Surface Methodology (RSM). Optimum glucose, yeast extract, and phenylalanine concentrations were determined to be 119.4 g 1−1, 3.7 g 1−1, and 14.8 g 1−1, respectively, for PPA production, and 163.8 g 1−1, 10.8 g 1−1, and 9.8 g 1−1, respectively, for biomass production. Under these optimum conditions, PPA concentration was enhanced to 1349 mg 1−1, which was 28% and 276% higher than the unoptimized bioreactor and shake-flask fermentations, respectively. Moreover, P. vulgaris biomass concentration was optimized at 4.36 g 1−1, which was 34% higher than under the unoptimized bioreactor condition. Overall, this study demonstrated that optimization of the fermentation media improved PPA concentration and biomass production in bench scale bioreactors compared to previous studies in the literature and sets the stage for scale up to industrial production.

Bioremediation of Zn, Cu, Mg and Pb in Fresh Domestic Sewage by Brevibacterium sp.

The study applied an isolated Brevibacterium sp. (MTCC 10313) for bioremediation of Zn, Cu, Mg and Pb in domestic sewage. Batch culture experiments were performed on both the fresh and stale sewage samples with glucose supplementation of 1-8g/l. Nutrient broth medium was prepared, sterilized and pH adjusted to 6.5-6.8. 1% of the Brevibacteria sp. stock was inoculated into the broth and maintained at 370C for 24hrs in shaker incubator at 120 rpm. Another 1% of fresh grown sub-culture of broth was inoculated into supplemented and sterilized samples. Optical Density was taken at 600nm, growth monitored over 12 days, cultured samples denatured with TCA and centrifuged, supernatants filtered and analyzed with AAS, Settled pellets oven dried, subjected to SEM analysis for morphology and constituents determination. Fresh sewage samples permitted bacterial growth and facilitated bioremediation of Zn, Cu and Mg through metal uptake and bioabsoption by Brevibacteria sp. This effectively reduced concentration of heavy metals, with treatment efficiency order Cu>Zn>Mg, and respective removal percentages of 77, 63 and 55. The optimum glucose concentration for effective bioremediation found as 2g/l for Zn and Cu, and 8g/l for Mg. Pb was resistant to bioremediation with Brevibacteria sp. Stale sewage produced inhibitory substances preventing adequate growth of bacterium with no bioremediation. Bioremediation with Brevibacteria sp. is found effective in removal of micro-units of Zn, Cu and Mg from domestic sewage. As a readily available low-cost agent, it is recommended for large- scale application on those metals while Pb should be further subjected to advanced treatments.

Impact of carbon source on β-cryptoxanthin production by Kocuria marina DAGII: a classical approach

Kocuria marina DAGII, a potent β-cryptoxanthin (β-CRX) producer, was previously isolated in our laboratory during routine screening of pigment producing bacteria. In this study, a classical approach of one factor at a time was applied for obtaining the maximum β-CRX yield by Kocuria marina DAGII. Growth kinetics and reducing sugar estimation were also done. The β-CRX production medium consisted of Yeast Extract (10 g/L), Bacteriological Peptone (5 g/L), NaCl (4 g/L), Glucose (0-20 g/L) and Maltose (0-20 g/L) at pH 7.9. Experiments were conducted in batch mode with 1% inoculum at 25˚C and 150 rpm for 5 days. The optimal glucose concentration was quantified by varying its concentration from 0 to 20 g/L in absence of maltose. Gradual increase in β-CRX yield was observed up to 7.5 g/L (3.6 mg/L). Beyond this concentration, β-CRX yield was almost constant. Simultaneously, optimal maltose concentration was determined by varying the concentration in range of 0-20 g/L in absence of glucose. Highest β-CRX production (3.25 mg/L) was observed at 10 g/L. Concentrations higher than 10 g/L were inhibitory, suggesting substrate inhibition of β-CRX by maltose. Validation experiment was conducted with Glucose and Maltose fixed at 7.5 g/L and 10 g/L, respectively. Significant increase in β-CRX yield (4.49 mg/L) was observed at 56 h of incubation with 60% utilization of reducing sugar. The bacterium exhibited regular growth pattern in all the experimental set ups. Monod’s model described the bacterial growth with maximum specific growth rate (μmax) of 0.2500 h-1 and 0.2024 h-1 for glucose and maltose, respectively. This suggests that bacterial growth is more influenced by glucose than maltose. However, for maximal β-CRX production, both the carbon substrates are essential.

Improved submerged Aspergillus ficuum phytase production in bench-top bioreactors by optimization of fermentation medium

Phytase is an important feed and food additive, which is used in diets to increase the absorption of divalent ions, amino acids, and proteins in the bodies and to decrease the excessive phosphorus release in the manure to prevent negative effects on the environment. To date, phytase has been mostly produced in solid state fermentations with insignificant production volumes. Thus, there is a need to produce phytase in submerged fermentations, which can be scaled-up for commercial productions. Additionally, optimization of fermentation medium has not been studied well in the literature. Therefore, this study has been undertaken to improve Aspergillus ficuum phytase production in submerged fermentations by optimizing important nutrients in the fermentation medium (glucose, Na-phytate, and CaSO4) using Box-Behnken design of Response Surface Methodology. Also, effects of pH and temperature on phytase activity were studied. Optimum glucose, Na-phytate, and CaSO4 concentrations were determined as 126, 14, and 1.1 g l–1, respectively. Additionally, pH 5.5 and 55 ºC were determined as optimum for the produced A. ficuum phytase activity. Under these conditions, phytase activity was increased to 3.45 U ml–1, which is about 50% higher than the previous results. Furthermore, the lowest activity loss was observed under 4 ºC storage conditions during 1 week of storage.

Development of Fed-Batch Cultivation Strategy for Efficient Oxytetracycline Production by Streptomyces rimosus at Semi-Industrial Scale

Oxytetracycline (OTC) production byStreptomyces rimosus was studied in batch and fed-batch cultures in shake flask and bioreactor levels using semi-defined medium. First, the effect of glucose concentration on OTC production and growth kinetics was studied intensively. The optimal glucose concentration in the medium was 15 g/L. Higher glucose concentrations supported higher biomass production by less volumetric and specific antibiotic production. Based on these data, cultivations were carried out at semi-industrial scale 15 L bioreactor in batch culture. At bioreactor level, cell growth and OTC production were higher compared to the shake flask culture by about 18 and 38%, respectively. During the bioreactor cultivation, glucose was totally consumed after only 48 h. Thus, the fed-batch experiment was designed for mono-glucose feeding and complete medium feeding to increase the OTC production by overcoming carbon limitations. The results showed that the fed-batch culture using constant glucose feeding strategy with rate of 0.33 g/L/h produced 1072 mg/L. On the other hand, feeding with complete medium resulted in 45% higher biomass but less OTC production by about 26% compared to mono-glucose fed culture. A further improvement in this process was achieved in by keeping the dissolved oxygen (DO) value at 60% saturation by cascading the glucose feeding pump with the DO controller. The later feeding strategy resulted in higher antibiotic production, reaching 1414 mg/L after 108 h.

Application of Response Surface Methodology for Xanthan Gum and Biomass Production Using Xan-thomonas campestris

Xanthan gum is an extracellular polysaccharide produced by various Xanthomonas species such as X. campestris. The objective of present study was to investigate the influence of different carbon and nitrogen sources on xanthan gum production by X. campestris. Using an ex- perimental Response Surface Methodology (RSM) complemented with a Central Composite De- sign (CCD), the impact of peptone, lactose, glucose and ammonium nitrate in medium were esti- mated for their individual and interactive effects on biomass and xanthan gum production. The optimal concentrations of peptone, lactose, glucose and ammonium nitrate for xanthan gum yield and biomass production was determined as 9.25 g/l, 53.37 mmol, 29.31 mmol and 4.58 g/l for xan- than gum yield and 6.77 g/l, 52.65 mmol, 38.12 mmol and 3.54 g/l for biomass production. Under the optimum experimental conditions, the xanthan gum yield reached to its maximum value (8.42 g/l). The results provide the support data for xanthan gum production on a large scale.

Enhanced Production of Nitrilase from Streptomyces sp. MTCC 7546 by Response Surface Method

Nitrilases are enzymes with varied applications preferably used in preparation of industrially important compounds as well as in bioremediation processes. The production of enzymes is influenced by medium compositions as some of the constituents of medium directly affect the enzyme synthesis. In the present study, the components of the medium are optimized by classical and response surface methodology to maximize the production of intracellular nitrilase from Streptomyces sp. MTCC 7546. Glucose was observed as the most suitable carbon source for production of nitrilase by ‘one factor at a time’. The optimal concentration of glucose (5 g/L) was set as zero coded level for further optimization study. A central composite design was employed to study the effect of interaction among glucose, yeast extract and mineral base and evaluated for maximum nitrilase yield. The nitrilase production of 11.54 U/mg was observed at 24 h in medium containing 6.5 g/L glucose, 1.0 g/L yeast extract and 220 mL/L mineral base with 10 mM of benzonitrile as inducer. A twofold increment from 5.95 U/mg in the enzyme yield was observed after the optimization study of response surface methodology.

Effects of carbohydrate, light, nitrogen and magnesium on In Vitro production of anthocyanin in apple

Anthocyanins as a secondary metabolite in plants, have a great nutritional value in human diet and a vast application in food industry. In-vitro culture of plant cells can be an alternative method for commercial production of large amounts of several important secondary metabolites. Some crab apples mostly native to Central Asia and Siberia, can produce anthocyanin in their various organs including fruit flesh. The aim of this study was to determine the best source and optimum concentration of carbohydrates, including sucrose, glucose, fructose, maltose and mannitol, magnesium, light intensity and nitrogen source to produce anthocyanin from in vitro callus culture of a red-fleshed crab apple. The results showed that the mannitol concentration of 3% plus 3% sucrose was the most effective carbohydrate treatment for anthocyanin production. Increasing mannitol concentration resulted in reduced anthocyanin content, callus growth index and fresh weight; while, callus dry weight increased. The highest anthocyanin content and the lowest callus growth index were observed in 6% sucrose among used concentrations. Glucose, fructose and maltose had weaker effects on anthocyanin content. Enhancing light intensity led to a significant upsurge in the amount of anthocyanins. Changing the nitrogen source also influenced anthocyanin content and the best combination of nitrogen source for producing anthocyanin was the 10 mM ammonium plus 18.8 mM nitrate or concentration of 5 mM ammonium plus 25 mM nitrate. Through adding magnesium to the medium boosted anthocyanin content up to 3 times and the most abundant anthocyanin was obtained at the highest concentration of magnesium.

Perioperative catabolism.

This article reviews the pathophysiology, clinical relevance, and therapy of the catabolic response to surgical stress. The key clinical features of perioperative catabolism are hyperglycemia and loss of body protein, both metabolic consequences of impaired insulin function. Muscle weakness and (even moderate) increases in perioperative blood glucose are associated with morbidity after major surgery. Although the optimal glucose concentration for improving clinical outcomes is unknown, most medical associations recommend treatment of random blood glucose>10mmol·L(-1). Neuraxial anesthesia blunts the neuroendocrine stress response and enhances the anabolic effects of nutrition. There is evidence to suggest that the avoidance of preoperative fasting prevents insulin resistance and accelerates recovery after major abdominal surgery. Current anticatabolic therapeutic strategies include glycemic control and perioperative nutrition in combination with optimal pain control and the avoidance of preoperative starvation. All these elements are part of Enhanced Recovery After Surgery (ERAS) programs.

Three-stage fermentation and kinetic modeling of bioflocculant by Corynebacterium glutamicum

Fermentation of bioflocculant with Corynebacterium glutamicum was studied by way of kinetic modeling. Lorentzian modified Logistic model, time-corrected Luedeking–Piret and Luedeking–Piret type models were proposed and applied to describe the cell growth, bioflocculant synthesis and consumption of substrates, with the correlation of initial biomass concentration and initial glucose concentration, respectively. The results showed that these models could well characterize the batch culture process of C. glutamicum at various initial glucose concentrations from 10.0 to 17.5g·L−1. The initial biomass concentration could shorten the lag time of cell growth, while the maximum biomass concentration was achieved only at the optimal initial glucose concentration of 16.22g·L−1. A novel three-stage fed-batch strategy for bioflocculant production was developed based on the model prediction, in which the lag phase, quick biomass growth and bioflocculant production stages were sequentially proceeded with the adjustment of glucose concentration and dissolved oxygen. Biomass of 2.23g·L−1 was obtained and bioflocculant concentration was enhanced to 176.32mg·L−1, 18.62% and 403.63% higher than those in the batch process, respectively, indicating an efficient fed-batch culture strategy for bioflocculant production.

Glucose application protects chloroplast ultrastructure in heat-stressed cucumber leaves through modifying antioxidant enzyme activity

To elucidate a physiological mechanism of heat stress mitigation by exogenous glucose, seedlings of Cucumis sativus cv. Jinchun No. 4 were pretreated with glucose and then exposed to normal (25/18 °C) and elevated (42/38 °C) temperatures. We investigated whether glucose can protect cucumber plantlets and chloroplast ultrastructure from heat and whether this protection is associated with antioxidant enzymes, proline, and soluble sugars. Heat inhibited plant growth, disorganized membranes of 86.33 % of chloroplasts, and elevated the content of malondialdehyde (MDA), superoxide radical (O2 .-), and hydrogen peroxide (H2O2). An optimum concentration of glucose was 30 mM as it significantly alleviated plant growth inhibition and obviously reduced the content of MDA, O2 .-, and H2O2 under the heat stress. The pretreatment with 30 mM glucose mitigated heat-induced damage of chloroplast ultrastructure and changes in leaf morphology more than 30 mM mannitol suggesting that glucose did not act only as osmolyte. Moreover, the glucose pretreatment increased activities of some antioxidant enzymes and enhanced the content of proline and soluble sugars under the heat stress, as well as the transcriptions of Cu/Zn-superoxide dismutase, Mn-superoxide dismutase, catalase, and glutathione reductase genes. We conclude that the pretreatment with 30 mM glucose protected chloroplast ultrastructure and enhanced heat tolerance of the seedlings by the increased activites of antioxidants and the content of proline and soluble sugars, and repressed accumulation of reactive oxygen species.

Anaerobic mineralization of 2,4,6-tribromophenol to CO2 by a synthetic microbial community comprising Clostridium, Dehalobacter, and Desulfatiglans

Anaerobic mineralization of 2,4,6-tribromophenol (2,4,6-TBP) was achieved by a synthetic anaerobe community comprising a highly enriched culture of Dehalobacter sp. phylotype FTH1 acting as a reductive debrominator; Clostridium sp. strain Ma13 acting as a hydrogen supplier via glucose fermentation; and a novel 4-chlorophenol-degrading anaerobe, Desulfatiglans parachlorophenolica strain DS. 2,4,6-TBP was debrominated to phenol by the combined action of Ma13 and FTH1, then mineralized into CO2 by sequential introduction of DS, confirmed using [ring-14C(U)] phenol. The optimum concentrations of glucose, SO42−, and inoculum densities were 0.5 or 2.5mM, 1.0 or 2.5mM, and the densities equivalent to 104copiesmL−1 of the 16S rRNA genes, respectively. This resulted in the complete mineralization of 23μM 2,4,6-TBP within 35days (0.58μmolL−1d−1). Thus, using a synthetic microbial community of isolates or highly enriched cultures would be an efficient, optimizable, low-cost strategy for anaerobic bioremediation of halogenated aromatics.

The Glucose Concentration‐Dependency of Spontaneous Activity in a Cultured Neuronal Network

SUMMARYCultured rat hippocampal network on a multielectrode array (MEA) dish is a useful model for analyzing network electrical dynamics and its developmental changes. Neurons autonomously form a complex network on an MEA dish and spontaneous electrical activity is often observed without any input from the external world. The spontaneous activity is generated by synaptic interactions between neurons and reflects an internal biochemical state of a whole neuronal network. The origin of electrical activity is electrochemical potential generated by active transport of ions, which requires catabolism of ATP. We elucidated the relationship between spontaneous electrical activity and external glucose concentration. The spontaneous activity changed transiently, depending on glucose concentrations. The number of electrical spikes in spontaneous activity increases depending on the concentration of external glucose concentration. Interestingly, this increase is not only suppressed but turn to decrease. In the case of glucose concentration is 17.56 mM, the number of activity is the most, and then it decreases in the case of glucose concentration is more than 20 mM. In addition, the decrease of neuronal activity at a high glucose concentration is not influenced by the blockade of inhibitory synaptic activity. These results suggest that a cultured neuronal network has optimal glucose concentration 17.56 mM, which corresponds to the concentration of glucose in a culture medium.

Optimization of Fermentation Medium and Culture Conditions of Hydrocarbon-Degrading Bacterium <i>Brevibacillus panacihumi</i> W25

Members belonging to the genus Brevibacillus had potentials in the bioremediation of hydrocarbon-contaminated soils. However, little is known about the fermentation medium and culture conditions of Brevibacillus panacihumi. The effect of concentrations of glucose and (NH4)2SO4, initial pH value and culture temperature on the biomass of B. panacihumi W25 was measured with single factor experiments, which was a hydrocarbon-degrading bacterium. Polynomial regression analysis showed optimal concentration of glucose and (NH4)2SO4, initial pH value and culture temperature were 45.2 g/L, 0.6 g/L, pH 7.3 and 30.3°C, respectively. The optimization of fermentation of B. panacihumi was reported for the first time.

Conversion of Cellulosic waste into fermentable sugar: Process optimization

Fossil fuel is depleting day by day throughout the world. This limitation along with the problem of Green House Gas (GHG) emissions leads findings for alternative energy that are environmentally and commercially feasible. Every day we are dumping lot of cellulosic waste materials into the environment from which we can produce valuable product such as ethanol to trim down the energy demand on fossil fuel. In the present study waste paper was treated to produce fermentable sugar using both conventional and enzymatic process. Acid catalyzed hydrolysis is conducted using sulfuric acid and the enzymatic process utilized municipal drain sludge. For acid catalyzed process optimum glucose concentration was found around 4 mg/ml for a loading of 1.5 g of untreated waste paper in 100 ml working volume at 25±2°C and a PH of 5 in about 1.5 hrs of hydrolysis. In case of enzymatic hydrolysis glucose yield was found around 2.5 mg/L for 10 ml sludge dosing in 100 ml working volume at 30°C±2 and PH of 7 in about 1.15 hrs of operation. In addition, base catalyzed hydrolysis is also observed with 5% NaOH and results around 3.3 mg/ml of glucose at room temperature and a PH of 13.0 in 1.5 hrs of hydrolysis DOI: http://dx.doi.org/10.3329/jce.v28i1.18107 Journal of Chemical Engineering, Vol. 28, No. 1, December 2013: 27-31

A fibrous bed bioreactor to improve the productivity of succinic acid by Actinobacillus succinogenes

AbstractBACKGROUNDSuccinic acid is one of the most important biorefinery platform chemicals. The fibrous‐bed bioreactor (FBB), comprising spiral cotton fiber packed in a modified bioreactor, is effective for anaerobic cell‐immobilized fermentation. In this study, fermentation production of succinic acid by Actinobacillus succinogenes using a FBB was investigated.RESULTSThe effect of different initial glucose concentrations on succinic acid production in batch fermentation in a FBB was examined, which indicated that the optimal initial glucose concentration was 55 g L‐1. In 10 batches of repeated‐batch fermentation, the average succinic acid productivity, concentration, and yield were 3.61 g L‐1 h‐1, 39.0 g L‐1, and 0.85 g g‐1, respectively. A maximum succinic acid concentration of 98.7 g L‐1 was reached in fed‐batch fermentation comprising four batches of fermentation, with a succinic acid yield of 0.89 g g‐1 and productivity of 2.77 g L‐1 h‐1.CONCLUSIONSuccinic acid fermentation by A. succinogenes in a FBB was successfully performed to enhance succinic acid productivity. And also, high succinic acid concentration with high reactor productivity and yield were simultaneously achieved in the FBB with fed‐batch fermentation. © 2013 Society of Chemical Industry

Effect of Environmental Factors on Production of Hyaluronic Acid by Streptococcus zooepidemicus

The effects of various environmental factors on the production of hyaluronic acid (HA) by Streptococcus zooepidemicus BCRC15414, the quantitation of HA by HPLC and morphology of the strain were examined. The cell growth was enhanced by aeration and agitation, but the influence of aeration was significantly higher. Agitation enhanced the HA production, but aeration has no beneficial effect for the HA production. Aeration and agitation significantly increased the kLa values; however, the kLa is not a determined factor for the HA production. A two-stage anoxic (static)-aerobic sequential culture, which is static for 24 h followed by aeration at 2 L/min, led to superior results both in biomass and HA production at the end of cultivation. The optimal initial glucose concentrations was about 20g/L, which led to highest HA production (0.51 g/L) after 24 h of cultivation in the two-stage anoxic (static)-aerobic sequential culture. The average molecular weight (Mw) of HA produced was 3.0×103 kDa, which was not affected by the glucose concentration used. Meanwhile, the addition of nisin enhanced the glucose consumption, biomass and HA production. Substrate inhibition on HA production was observed for S. zooepidemicus BCRC15414 when the initial glucose concentration was above the optimal value ( ＞ 20 g/L); no substrate inhibition on cell growth was observed. In the quantitation of HA, HA concentration analyzed by HPLC method was more accurate than that analyzed by carbazole method. Distinctive differences of morphologies were observed for the low and high HA producing strains, which provides a simple and important tool that enable one to screen and identify the ability of a strain to produce high titer of HA.

Improvement of butanol fermentation by supplementation of butyric acid produced from a brown alga

This study investigated butanol fermentation using glucose and culture broth containing butyrate from the butyrate fermentation of a brown alga, Laminaria japonica. Prior to the use of the biologically-produced butyrate, the initial glucose in tryptone-yeast extract acetate (TYA) medium was first optimized for butanol fermentation using Clostridium saccharoperbutylacetonicum N1-4 ATCC 27021T. Then, a commercially-acquired (synthetic) butyrate was supplemented to the TYA medium containing the optimal glucose concentration (around 30 and 60 g/L). According to the experimental results, the highest butanol carbon yield (0.580 C-mol/C-mol) was obtained from the fermentation of 36.65 g/L glucose and 7.29 g/L synthetic butyrate. Fermentation of a similar amount of glucose (32.28 g/L) in the absence of butyrate gave a butanol carbon yield of 0.402 C-mol/C-mol. For the experiment with fermented butyrate, a 100 g/L biomass of brown alga was fermented by Clostridium tyrobutyricum ATCC 25755 and the culture broth containing butyrate was used to prepare TYA medium after removing the bacterial cells. Fermentation using the synthetic butyrate and the biologically-produced butyrate (4.95 g/L) gave a comparable butanol concentration (13.23 g/L) and butanol carbon yield (0.513 C-mol/C-mol). Overall, this study proved that the addition of fermented butyrate from brown alga fermentation could be an effective way to improve butanol production. Furthermore, the reuse of spent medium and the absence of rigorous purification of the broth containing butyrate would lower the production cost of the fermentation.

Growth and Fermentation Characteristics of Saccharomyces cerevisiae NK28 Isolated from Kiwi Fruit

The influences of glucose concentration, initial medium acidity (pH), and temperature on the growth and ethanol production of Saccharomyces cerevisiae NK28, which was isolated from kiwi fruit, were examined in shake flask cultures. The optimal glucose concentration, initial medium pH, and temperature for ethanol production were 200 g/l, pH 6.0, and 35oC, respectively. Under this growth condition, S. cerevisiae NK28 produced 98.9 ± 5.67 g/l ethanol in 24 h with a volumetric ethanol production rate of 4.12 ± 0.24 g/l·h. S. cerevisiae NK28 was more tolerant to heat and ethanol than laboratory strain S. cerevisiae BY4742, and its tolerance to ethanol and fermentation inhibitors was comparable to that of an ethanologen, S. cerevisiae D5A.

Optimization of Liquid Fermentation Conditions and Encapsulation for Nattokinase Production

Nattokinase is a potent fibrinolytic enzyme. The composition of the medium for nattokinase production was optimized respectively. Effect of glucose concentration on nattokinase activity and optimal glucose concentration in fermentation process were investigated. L9 (33) orthogonal array design was applied to investigate the effects of Na2HPO4 to NaH2PO4 ratio, CaCl2, MgSO4 on nattokinase activity and search for the optimal concentrations of the three inorganic salts. The results showed that Na2HPO4/NaH2PO4 was the main factor to affect nattokinase activity, then was CaCl2 and MgSO4 in turn. The optimum concentrations of liquid fermentation medium components were as followed: glucose 1% , Na2HPO4 to NaH2PO4 ratio 0.4% : 0.1% , CaCl2 0.01% and MgSO4 0.1%. Under the optimal conditions, the nattokinase activity was equivalent to 871.56 urokinase IU/mL. To mask the smelly flavor, the nattokinase powders were encapsulated. The research will be helpful to the development of nattokinase products.