Showing papers on "Growth medium published in 2011"

Optimization of various growth media to freshwater microalgae for biomass production

Abstract: In recent decades, microalgae have acquired attention from pharmaceuticals to biofuels. The growth and total chorophyll content of three economically important microalgae (Chlorella sp. NTAI01, Monoraphidium sp. NTAI02 and Scenedesmus sp. NTAI03) isolated from fresh water body in five selected culture media on different days of incubation was studied for biomass production. Biomass feedstock has reviewed great interest to be used as an alternative and renewable source of energy. All the three organisms showed varied growth pattern and total chlorophyll content in different culture media. However the growth and total chlorophyll content of Chlorella sp. NTAI01 and Monoraphidium sp. NTAI02 was optimum in Half strength Chu 10 medium. In case of Scenedesmus sp. NTAI03 the growth and total chlorophyll content was found to be significant in Bolds Basal medium. The Acidified Bolds Basal medium and BG-11 medium fairly supports the growth of all the three microalgae whereas the Modified Hoaglands medium does not support the microalgal growth. The optimized growth medium will be used for biomass production for biofuel application.

Rhizobia enhance acquisition of phosphorus from different sources by soybean plants

Abstract: Some rhizobia can convert insoluble P into available forms for plant growth but the underlying mechanisms for this are not understood. In this study, the function of rhizobia in P acquisition from P sources for soybean was studied. Four rhizobial strains were employed to evaluate their phosphate-solubilizing (PS) activity, their ability to mediate pH changes in growth medium for different P sources, and IAA production. A sand culture experiment using different P sources was carried out to characterize P acquisition changes of soybean plants with or without rhizobium inoculation. Rhizospheric acidification in soybean was further analyzed in hydroponics. Our results showed that all the tested rhizobial strains exhibited significant PS activity for different P sources in the order of Ca-P>Al-P>Phy-P≥Fe-P as indicated by the halo/colony ratio technique and increased Pi percentage in the solid and liquid phases, respectively. Furthermore, all of the rhizobial strains could acidify the growth medium for all P sources except Phy-P, but only three of them produced IAA. Compared to non-nodulated plants, the nodulated plants had greater plant biomass and P content in sand culture for all the tested P sources, especially for Ca-P. Moreover, H+ and total acid exudation was more significantly enhanced in the nodulated plants in hydroponics. Our results suggested that the PS ability of rhizobia is more related to acidification of the growth medium than IAA production. Rhizobium inoculation could enhance P acquisition in soybean, especially on soils where Ca-P is the primary P source, and the primary mechanism for rhizobial-mediated P solubilization appears to be via Pi remobilization of nodulated roots through rhizospheric acidification.

Modification of the Technical Properties of Lactobacillus johnsonii NCC 533 by Supplementing the Growth Medium with Unsaturated Fatty Acids

Abstract: The aim of this study was to investigate the influence of supplementing growth medium with unsaturated fatty acids on the technical properties of the probiotic strain Lactobacillus johnsonii NCC 533, such as heat and acid tolerance, and inhibition of Salmonella enterica serovar Typhimurium infection. Our results showed that the membrane composition and morphology of L. johnsonii NCC 533 were significantly changed by supplementing a minimal Lactobacillus medium with oleic, linoleic, and linolenic acids. The ratio of saturated to unsaturated plus cyclic fatty acids in the bacterial membrane decreased by almost 2-fold when minimal medium was supplemented with unsaturated fatty acids (10 μg/ml). The subsequent acid and heat tolerance of L. johnsonii decreased by 6- and 20-fold when the strain was grown in the presence of linoleic and linolenic acids, respectively, compared with growth in oleic acid (all at 10 μg/ml). Following acid exposure, significantly higher (P < 0.05) oleic acid content was detected in the membrane when growth medium was supplemented with linoleic or linolenic acid, indicating that saturation of the membrane fatty acids occurred during acid stress. Cell integrity was determined in real time during stressed conditions using a fluorescent viability kit in combination with flow cytometric analysis. Following heat shock (at 62.5°C for 5 min), L. johnsonii was unable to form colonies; however, 60% of the bacteria showed no cell integrity loss, which could indicate that the elevated heat inactivated vital processes within the cell, rendering it incapable of replication. Furthermore, L. johnsonii grown in fatty acid-enriched minimal medium had different adhesion properties and caused a 2-fold decrease in S. enterica serovar Typhimurium UK1-lux invasion of HT-29 epithelial cells compared with bacteria grown in minimal medium alone. This could be related to changes in the hydrophobicity and fluidity of the membrane. Our study shows that technical properties underlying probiotic survivability can be affected by nutrient composition of the growth medium.

Functional Characterization of fst1 in Fusarium verticillioides During Colonization of Maize Kernels

Abstract: The putative hexose transporter gene fst1 in Fusarium verticillioides was identified previously by microarray analysis as a gene that was more highly expressed during colonization of autoclaved maize endosperm than germ. In contrast to a previous study, in which disruption of fst1 did not affect growth of the pathogen on autoclaved maize kernels, in the current study, we demonstrated that disruption of fst1 delayed growth and symptom development on wounded maize ears. Characterization of the fst1 promoter revealed that regulation of fst1 expression was similar to that of fumonisin biosynthetic (fum) genes; expression was highest during growth on endosperm tissue and repressed by elevated concentrations of ammonium in the growth medium. With a fluorescent tag attached to FST1, the protein localized transiently to the periphery of the cells near the plasma membrane and in vacuole-like structures, suggesting that membrane-localized FST1 was internalized and degraded in vacuoles. Expression of fst1 in a yeast strain lacking hexose transporter genes did not complement the yeast mutation, suggesting that FST1 does not transport glucose, fructose, or mannose. The results indicate a functional role for FST1 in pathogenesis during the colonization of living kernels.

A Dehydrogenase Activity Test for Monitoring the Growth of Streptomyces Venezuelae in a Nutrient Rich Medium

Abstract: Jadomycin is a novel antibiotic that has shown activities against bacteria, yeasts and fungi as well as cytotoxic properties to cancer cells. Because of the wide range of its inhibitory actions, jadomycin shows promise as a novel antibiotic and cancer treatment drug. Streptomyces venezuelae are aerobic bacteria that are capable of producing jadomycin when shocked by alcohol in a nutrient deprived amino acid rich medium. The size of the bacterial population that is transferred from the growth medium to the production medium can significantly affect the jadomycin yield. Therefore, the number of transferred bacteria must be accurately measured. In this study, a dehydrogenase activity measurement test was developed for S. venezuelae using triphenyl tetrazolium chloride (TTC) to measure the cell growth and activity in maltose-yeast extract-malt extract (MYM) broth. The dehydrogenase activity was determined by measuring the visible color changes of the TTC to triphenyl formazan (TF). The test conditions which included extraction solvent, number of extractions, incubation time, incubation temperature and medium pH were evaluated. The results showed that the triphenyl formazan was related to the number of cells. Methanol was better able to permeate the cells and extract higher amount of TF than ethanol. The amount of TF increased with the number of extractions for both solvents. A lower medium pH and/or lower temperature produced the highest amount of TF. The best test conditions that produced the highest TF yield were three extractions using methanol after an incubation time of 1 hour at a temperature of 30oC and a medium pH of 6.

Optimization of the growth of and α-amylase production by Bacillus subtilis IP 5832 in shake flask and laboratory fermenter batch cultures

Abstract: Cell growth and the level of α-amylase in response to the carbon and nitrogen sources used for the growth of the strain Bacillus subtilis IP 5832 were examined. Based on the amylase productivity level in shake flask cultures after 24 hours of growth, the growth medium containing starch and peptone was selected as the best medium. Amylase production was greatly reduced when glutamate or citrate as sources of carbon were used. Experiments performed at different initial concentrations of starch showed that although the strain grew well with all the starch concentration used, 0.5 % starch was necessary for maximum α-amylase production, inducing 1.55 IU mL-1 of amylase to be secreted after 8 h of cultivation in shaking flasks. During the batch fermentation of B. subtilis IP 5832 strain in 2 L laboratory fermenter, a 60 % higher activity (2.5 IU mL-1) was obtained. The production of the enzyme was directly related to the growth of the strain. Maximum enzyme activity was obtained at the beginning of the stationary growth phase.

Multiple TORC1-Associated Proteins Regulate Nitrogen Starvation-Dependent Cellular Differentiation in Saccharomyces cerevisiae

Abstract: Background: The budding yeast Saccharomyces cerevisiae undergoes differentiation into filamentous-like forms and invades the growth medium as a foraging response to nutrient and environmental stresses. These developmental responses are under the downstream control of effectors regulated by the cAMP/PKA and MAPK pathways. However, the upstream sensors and signals that induce filamentous growth through these signaling pathways are not fully understood. Herein, through a biochemical purification of the yeast TORC1 (Target of Rapamycin Complex 1), we identify several proteins implicated in yeast filamentous growth that directly associate with the TORC1 and investigate their roles in nitrogen starvation-dependent or independent differentiation in yeast. Methodology: We isolated the endogenous TORC1 by purifying tagged, endogenous Kog1p, and identified associated proteins by mass spectrometry. We established invasive and pseudohyphal growth conditions in two S. cerevisiae genetic backgrounds (S1278b and CEN.PK). Using wild type and mutant strains from these genetic backgrounds, we investigated the roles of TORC1 and associated proteins in nitrogen starvation-dependent diploid pseudohyphal growth as well as nitrogen starvation-independent haploid invasive growth. Conclusions: We show that several proteins identified as associated with the TORC1 are important for nitrogen starvationdependent diploid pseudohyphal growth. In contrast, invasive growth due to other nutritional stresses was generally not affected in mutant strains of these TORC1-associated proteins. Our studies suggest a role for TORC1 in yeast differentiation upon nitrogen starvation. Our studies also suggest the CEN.PK strain background of S. cerevisiae may be particularly useful for investigations of nitrogen starvation-induced diploid pseudohyphal growth.

Isolation and characterization of -glucosidase producing bacteria from different sources

Abstract: β-Glucosidase producing microorganisms are potential sources that can be employed for bioconversion of cellulose. In the present study, nine morphologically different bacterial isolates were isolated from dairy effluent and seven were isolated from fermented barley. Four of the bacteria from the dairy effluent and five from barley source were found to possess β-glucosidase activity. This activity was tested by growth in medium supplemented with esculin and ferric ammonium citrate. The esculin positive strains from both the sources were characterized biochemically and checked for their ability to transform ginsenoside Rb1. The growth medium and the pH for maximum growth were optimized.

Growth and nitrate assimilation in tomato (Solanum lycopersicon) grown with different nitrogen source and treated with cadmium

Abstract: In tomato seedlings, the effects of Cd on growth and activity of enzymes involved in nitrate assimilation were studied on different nitrogen sources After one week on basal growth medium, seedlings were transferred and grown for 14 days on a medium containing 5 mM nitrate, 5 mM ammonium or varying ratios of nitrate to ammonium In each nitrogen medium, plants were divided into control and Cd treated In nitrate—rich medium, plant dry weigh was improved while growth was more inhibited by Cd stress than in ammonium—rich medium Regardless of nitrogen source, Cd treatments decreased nitrate contents in leaves and roots Nitrate reductase and nitrite reductase activities were decreased by presence of ammonium in culture medium Cd treatments inhibited NR and NiR activities independently of nitrogen form and plant organ It could be concluded that tomato plants preferred nitrate as a nitrogen source where as external ammonium was found to inhibit growth The addition of ammonium in nutrient solution

Nutritional factors affecting the production of -amylase in Lasiodiplodia theobromae Pat.

Abstract: Lasiodiplodia theobromae Pat. grew and sporulated at 27 °C and at pH 6.0 in a synthetic medium containing potassium nitrate as sole nitrogen source. �-amylase activity was detected in the growth medium. Bread, starch, maltose, sucrose, lactose, glucose and gala ctose supported growth and �-amylase production, indicative of constitutive production of the enzyme. Bread see med to be most supportive with optimum activity expressed as approximately 29 units per mg protein within 216 and 240 hr. Extracted crude enzyme, with bread as carbon source and potassium nitrate as sol e nitrogen source, was partially purified by ammoni um sulphate precipitation and dialysis. Specific activ ity of the enzyme increased 70% and 0.7 fold with a yield of 57.4% on dialysis. Bread as carbon source of growth of this organism is recommended for large scale production of this enzyme, industrially.

Effect of the d-glucose analog, d-allose, on the growth of Arabidopsis roots

Abstract: Although d-glucose increased the root growth of Arabidopsis seedlings, d-allose (a d-glucose epimer at the third carbon atom) inhibited the root growth at concentrations >0.1 mmol L−1 and the inhibition increased with increasing d-allose concentrations. Allitol (a reduction product of d-allose) did not show any significant effect on the growth. The addition of d-glucose into the growth medium of Arabidopsis reversed the d-allose-induced growth inhibition, which suggests that the inhibition is not caused by the toxicity of the accumulation of d-allose and/or its metabolites in the seedlings. d-Allose is phosphorylated by hexokinase, using ATP and phosphate, to allose-6-phosphate, with no known capacity for further metabolism. The addition of phosphate into the growth medium did not affect the d-allose-induced growth inhibition and d-allose did not reduce the ATP level in the roots. These results suggest that the inhibition is not due to phosphate starvation and ATP depletion. d-Mannoheptulose, a specific competitive inhibitor of hexokinase, defeated the d-allose-induced growth inhibition. Hexokinase is known to have a sugar-sensing function and possibly triggers a signal cascade, resulting in the change of several gene expressions. Therefore, the phosphorylation of d-allose by hexokinase might trigger a signal cascade, resulting in the inhibition of Arabidopsis root growth. This is probably a useful model system for studies of the hexokinase-mediated sugar-sensing function and for developing new types of weed-control agents.

Sugars waste, an alternative growth and complete medium for fast growing Rhizobium cells

Abstract: The sugar waste (molasses) was tested for various physiochemical parameters. After examination of various physiochemical parameters, growth and population count ofRhizobium meliloti MTCC-100 was monitored at different concentrations of sugar waste (10, 20, 30 and up to 100%) in terms of optical density (OD) and colony forming unit (C.F.U.). Growth and cell count of Rhizobium were highest in 10% sugar waste concentration. Growth pattern of the bacteria was observed at 10% sugar waste along with different synthetic media (tryptone yeast extract medium, rhizobium minimal medium and yeast extract medium). Growth of bacteria in 10% sugar waste was found to be superior to standard media (TY, RMM and YEM) used for Rhizobium. The important environmental parameters like pH and temperature were optimized for 10% sugar waste as growth medium. A pH of 7.0 and temperature of 28°C were found to be the most suitable for the fast growing R. meliloti MTCC-100. Key words: Rhizobium meliloti, sugar waste, synthetic media, colony forming unit.

The correlations between TCA-glyoxalate metabolite and antibiotic production of Streptomyces sp. M4018 grown in glycerol, glucose, and starch mediums.

Abstract: The alterations of organic acids citrate, α-ketoglutarate, succinate, fumarate, malate production together with isocitrate lyase activity as a glyoxalate shunt enzyme, and antibiotic production of Streptomyces sp M4018 were investigated in relation to changes in the glucose, glycerol and starch concentrations (5–20 g/L) after identification as a strain of Streptomyces hiroshimensis based on phenotypic and genotypic characteristics. The highest intracellular citrate and α-ketoglutarate levels in 20 g/l of glucose, glycerol, and starch mediums were 399.47 ± 4.78, 426.93 ± 6.40, 355.84 ± 5.38 ppm and 444.81 ± 5.12, 192.96 ± 2.26, 115.20 ± 2.87 ppm, respectively. The highest succinate, malate, and fumarate levels were also determined in 20 g/l of glucose medium as 548.9 ± 11.21, 596.15 ± 8.26, and 406.42 ± 6.59 ppm and the levels were significantly higher than the levels in glycerol and starch. Extracellular organic acid levels measured also showed significant correlation with carbon source concentrations by showing negative correlation with pH levels of the growth medium. The antibiotic production of Streptomyces sp. M4018 was also higher in glucose medium as was the case also for organic acids when compared with glycerol. On the other hand, there is no production in starch.

Inducible expression of calreticulin-N58 in Pichia pastoris by high density cell culture

Abstract: Calreticulin-N58 (CRT-N58), an active fragment of calreticulin with anti-angiogenesis activity, was expressed in P. pastoris by high density cell culture. Calreticulin-N58 DNA was synthesized by PCR and cloned to plasmid pPIC9 K resulting in the plasmid pPIC9 K-crt-N58 which was then transformed into P. pastoris GS115. The fermentation was carried out in a 50 l bioreactor with 20 l modified growth medium recommended by Invitrogen at 30°C. The cells were first grown in glycerol-PTM4 trace salts for 24 h. When the cell density was grown to A(600) = 135, methanol-PTM4 trace salts was added to induce the expression of calreticulin-N58. During the fermentation, dissolved oxygen level was maintained at 20-30%, pH was controlled at 5 by adding 7 M NH(4)OH. After 52 h of induction, the yield of secreted calreticulin-N58 was 70 mg/l and biomass growth was 293 as measured by absorption of 600 nm. The secreted calreticulin-N58 was purified to a purity of 100% by the use of SP-Sepharose FF ion-exchange chromatography (Pharmacia Biotech. NJ, USA) and desalted with ultrafiltration device (Millipore, Bedford, MA, USA). The recombinant calreticulin-N58 induced endothelial cell apoptosis and inhibited the angiogenesis on the CAM.

Investigation of Growth Medium Supplementation and Ethanol Tolerance of the Yeast Saccharomyces cerevisiae

Abstract: Ethanol tolerance is one of the most important properties of yeasts used for bioethanol production, and has been correlated with plasma membrane fluidity. This study investigates yeast membrane fluidity and ethanol tolerance, particularly in relation to proline and inositol supplementation. Three Saccharomyces cerevisiae strains (A12, PDM and K7) were selected, based on reported stress tolerance and ethanol productivity; an ethanol tolerant baker’s yeast (A12), a wine yeast (PDM) and a sake yeast (K7), the latter produce up to 17 and 17.5 %(v/v) ethanol, respectively. To determine the feasibility of these strains and supplementation for bioethanol production, a model system was devised using Yeast Nitrogen Base (YNB) with 18% (w/v) sucrose. YNB was chosen for its defined and consistent composition (limiting variation) and for its lower fluorescent background (enabling membrane fluidity assessment in situ). However growth of all strains was inconsistent and ferments stuck at high sugar levels. This was likely due to insufficient nitrogen or other essential nutrients, and could be ameliorated by a complex but undefined medium but with high and inexact levels of proline and inositol. In order to allow unequivocal discrimination of supplement effects, experiments were continued with media similar to previous laboratory studies; YNB with 2% (w/v) glucose. When cultured in YNB with 2% (w/v) glucose, the three strains had similar growth rates and performance, although K7 maintained significantly higher viability. Comparison of generalized polarization (GP) of laurdan-labelled cells indicated that PDM had the highest membrane fluidity, followed in order by K7 and A12. Conversely A12 had the highest ethanol tolerance, followed in order by K7 and PDM, so unlike some published reports, higher ethanol tolerance related to lower membrane fluidity. Furthermore in comparison to 6 h cultures, 24 h cultures of all strains had lower membrane fluidity and higher ethanol tolerance. Two approaches were used to assess ethanol tolerance. The total plate count (TPC) is widely used to assess ethanol tolerance, while methylene violet staining has been proposed as a rapid alternative. Correlation analysis showed only weak correlations between viability assessment by methylene violet staining and viability by TPC, membrane fluidity by GP or culture age. In contrast there were strong correlations between membrane fluidity by GP, viability by TPC and culture age. Despite showing promise in previously published studies as a stress tolerance enhancer, proline supplementation did not lead to any consistent significant change in membrane fluidity or ethanol tolerance. The only significant effect was the higher GP of the PDM strain with 0.5 g/L proline. However, no significant differences between levels of supplementation were detected in viability reduction in ethanol-stressed cultures (either by TPC or methylene violet staining). Therefore further study is needed to confirm this result. The present study failed to confirm reports that inositol supplementation increases ethanol tolerance. No significant changes of either GP or viability reduction upon ethanol stress were found when the medium was supplemented with various levels of inositol. Further investigation, including more variations in concentration, is needed to elucidate this possibility. In summary, of the three S. cerevisiae strains tested, A12 seems to be the best for bioethanol production, followed by K7 and then PDM. Some relationships were found between culture age, ethanol stress tolerance and membrane fluidity, although supplementation of cultures with proline or inositol did not seem to enhance culture performance or ethanol tolerance.

Gelatinous substance based growth medium filtration device and method

Abstract: Growth medium filtration devices are provided which are particularly well adapted to sterilize gelatinous substance based growth mediums including agar, agarose and other polysaccharide derived growth mediums for use in agar plates and the like for culturing microorganisms. The devices may include one or more filtration units and at least one heat source for filtering the growth medium in a heated filtration process. Methods of filtering a growth medium, such as an agar growth medium, and methods of preparing a growth medium having low gelling point and lower molecular weight characteristics are also provided.

Nitrogen source affects glutamine synthetase activity in Pantoea sp.; bacterium inoculation promotes rice seedlings' growth

Abstract: This study investigated the influence of different sources of nitrogen on Glutamine synthetase (GS) activity of Pantoea sp. strain 9C and the effect of inoculation with the bacterium on the growth medium of rice seedlings. The growth curves of 9C showed lowest cell concentration in LGI medium free of nitrogen and highest cell concentration in LGI medium supplied with 5 mmol/L of serine or asparagine. The measure of GS activity of 9C was accomplished by culturing the bacteria for 96 h using the biosynthetic method. Cellular rupture was carried out by ultrasonic waves or lysozyme. GS activity was detected in cytosol and in cellular debris. GS activity in supernatant was influenced by the source of nitrogen; alanine increased the activity while ammonium inhibited it. The bacterium increased the seedlings fresh weight and height of the shoot, and the length and number of rice seedlings’ roots. Key words: Diazotroph, endophyte, glutamine synthetase, Pantoea, plant growth promoting bacteria, rice.

Glucoamylse Production in Submerged Co-Culture System of Bacillus amyloliquefaciens and Rhizopus cohnii

Abstract: We developed novel method for producing glucoamylase (GA) from gelatinized rice flour by co-culturing Bacillus amyloliquefaciens NBRC 14141 and Rhizopus cohnii P5. In liquid culture, the acidification of the growth medium due to the growth of R. cohnii prevented the growth of B. amyloliquefaciens; however, the B. amyloliquefaciens protease lysed R. cohnii cells, which decreased the production of GA. This antagonism was repressed by high concentrations of ammonium acetate in the growth medium. However, since low pH or high ammonium acetate concentrations inhibited the initial growth of B. amyloliquefaciens, it needed to be precultured without ammonium acetate. However, preculturing B. amyloliquefaciens for 48 h led to overproduction of protease, which inhibited the growth of R. cohnii. As a result, the maximum GA activity (740 U/ml) was obtained when B. amyloliquefaciens was precultured for 24 h followed by inoculation with R. cohnii in the presence of 3.84% (w/v) of ammonium acetate. These results indicated that GA can be produced at high levels

The beetroot juice as a bacterial growth and maintenance medium for many pathogenic bacteria

Abstract: In a pioneer study in Iraq, a water extract (juice) from the root of Beta vulgaris (beetroot) was prepared under sterile conditions, then used for the first time as experimental bacterial growth medium for the growth of the bacteria: Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae; the juice was used as alternative growth medium for the nutrient agar and nutrient broth for the growth of these genera in the laboratory. All the genera showed active growth after (24) hours when the juice used directly as a liquid growth medium, the medium preserve these bacteria viable for (7) days. The juice was used also to enrich the agar-agar and cultured with the same bacteria; it showed a noticeable growth lasted for (10) days. The results suggest that this juice is a suitable growth medium for these bacteria, and it could be used instead of the growth media that mentioned above which used in the cultivation of these bacteria in the laboratory. It also represents important, rich nutritional environment not less important than those that is found in the other media.

Device for simulation

Abstract: An in-vitro solution for simulating the growth of microbes in the presence of mammalian cells is disclosed. A layer of mammalian cells is held in a cell culture well (W1)in the presence of growth medium. A circulation unit (U1)is configured to circulate,at least a part of growth medium and microbes discarded via outlet means (O1-1) from the cell culture well (W1), back to the cell culture well (W1) via inlet means (I1-1), such that a part of the discarded growth medium is replaced with fresh growth medium. A control unit (E1)is configured to control the operation of the circulation unit (U1) based on a pH measurement carried out in the growth medium, such that the conditions in the cell culture well (W1) are kept non-toxic to the mammalian cells.

Yeast biomass production from rest products for fish feed

Abstract: Proper nutrition plays a key role in the growth of fish. However, limited supply of raw material for fish feed has posed problem for the ever-growing Aquaculture. Waste water from food industries (e.g. diaries and slaughterhouses) contains considerable amounts of proteins and fats to be used as fish feed. Similarly, glycerol which is a by-product in biodiesel production can be used as carbon source by yeast. Linseed oil can be useful as a source of fatty acids. In this study we investigate the potential of waste from paper and beer industries as a growth medium for yeast. We used two different concentrations of Glycerol and Linseed oil. Media was inoculated with yeast and cultured for 48 hours. To determine the growth of yeast, OD (Optical Density) was measured for each sample at three hours intervals. Our results show that waste from beer industry is very promising as compared to waste from paper industry for the growth of yeast. Moreover, all strains of yeast showed better growth when lower concentrations of glycerol and linseed oil were added to beer water as compared to high concentrations.

Development of Media for the Cultivation of Enterobacter amnigenus GG0461 and its Nitrate Uptake

Abstract: To remove excess nitrate from the agricultural environments, Enterobacter amnigenus GG0461 has been isolated as a bacterial strain having high capability of nitrate uptake activity. This strain was able to remove nitrate more than 3,000 ppm (50 mM) in the Pseudomonas agar F (PAF) medium. Therefore, it could be a candidate strain for a nitrate scavenger in the various contaminated environments, such as agricultural soils, livestock sewage, and industrial wastewater. In order to develop medium for the large-scale production of the strain GG0461, each component of PAF medium was replaced with the corresponding commercial product and the optimal conditions for bacterial growth and nitrate uptake activity were measured. Glycerol was replaced with the commercially available product and the nitrogen source was substituted with commercial tryptone, yeast extract, soybean meal, and fermented fish extract. Bacterial growth and nitrate uptake activity were maximal in the media containing 2% tryptone, followed by yeast extract, soybean meal, and fermented fish extract. The pH of the growth medium containing 2% tryptone was decreased by the bacterial nitrate uptake, suggesting that the nitrate uptake is mediated by a nitrate/proton antiporter. This result shows that the medium containing commercial tryptone was good enough for the physiological activity of the strain GG0461. Each component of PAF medium was successfully replaced with the corresponding commercial product except peptone. In conclusion, the composition of medium for the cultivation of the strain GG0461 was determined as 2% tryptone, 1% glycerol, plus required salts according to the composition of PAF medium.