Broth Filtrate Research Articles

Medium Optimization for the Production of Antioxidants from Aspergillus candidus

The objective of this study was to optimize the factors for the production of antioxidant from Aspergillus candidus CCRC 31543. Extracts of broth filtrate had higher antioxidant activity (inhibition of peroxidation [IP] >98%) when sucrose or lactose was used as a carbon source. Sucrose in the medium also resulted in a higher yield of extracts. Ethyl acetate extracts had the highest yield and antioxidant activity compared with the other two solvents. For the production of antioxidant, inorganic nitrogen sources were found to be more suitable than organic nitrogen sources, and ammonium sulfate was better than sodium nitrate. Yeast extract had a strong influence on the yield of antioxidant extracts. Both mycelium and broth filtrate of A. candidus CCRC 31543 showed similar antioxidant activity (IP = 95%), and they also had similar extraction yields.

Effects of surfactants on emulsification and secondary structure of lysozyme in aqueous solutions

This paper reports our investigations on the secondary structure of lysozyme in aqueous solution with D 2O and comparing systems emulsified with ionic and non-ionic amphiphiles, respectively. The opposite effect of concentration of surfactants on the lysozyme aqueous system was studied and the activity of lysozyme by the turbidimetric assay with different kinds of surfactant was compared. The effect of different surfactants on emulsification volume formed was observed and discussed. The different interactive patterns between lysozyme and ionic and non-ionic surfactants, such as sodium dodecyl sulfate (SDS), cetyl trimethyl ammonium bromide (CTAB) and Triton-X100 (Isooctoylphenoxypolyethoxy ethanol), respectively, was studied with FTIR. A simple relationship between the secondary structure and denaturation of protein is given for the emulsification of lysozyme in aqueous solutions. It is important for understanding the stabilization and avoiding the emulsions in the extraction process that the interactions between the proteins and surfactants which leads to the formation of such complexes are characterized. The utility of surfactants as a de-emulsifying agent for the commercial process to extract penicillin G from the filtrate of fermentation broth was consistent with these results.

Culture filtrate of Bacillus atrophaeus induced abnormalities in Ascosphaera apis

The antifungal activity of broth filtrate of Bacillus atrophaeus isolate #35 was studied on Ascosphaera apis (Ascosphaeraceae—Ascomycota), a pathogen of honeybee larvae. Inhibition of hyphal growth was evident but varied with batch of fermentation broth, dilution, and duration of treatment. Significant growth inhibition and hyphal lysis were observed when the strength of the culture filtrate was at maximum. At the scanning electron microscope level, the treatment induced morphological abnormalities including swelling, stunting, constriction, and rupture of hyphae. We also found aberrations in the plasma membrane ranging from a serrated appearance in profile to total degradation in lysed hyphae. In some hyphae, almost all membrane systems including mitochondria, endoplasmic reticulum, and Golgi bodies, had changed drastically and in many cases formed membranous inclusions. Hyphae also contained electron-dense, bizarrely shaped structures that extended throughout. In the most inhibitory treatment, the hyphal wall was uneven in thickness, yet had N-acetyl-D-glucosamine label equal to that of the control, suggesting the irregular thickness of the wall was due to deposition of other polysaccharides.

Culture Filtrate of Bacillus atrophaeus Induced Abnormalities in Ascosphaera apis

The antifungal activity of broth filtrate of Bacillus atrophaeus isolate #35 was studied on Ascosphaera apis (Ascosphaeraceae—Ascomycota), a pathogen of honeybee larvae. Inhibition of hyphal growth was evident but varied with batch of fermentation broth, dilution, and duration of treatment. Significant growth inhibition and hyphal lysis were observed when the strength of the culture filtrate was at maximum. At the scanning electron microscope level, the treatment induced morphological abnormalities including swelling, stunting, constriction, and rupture of hyphae. We also found aberrations in the plasma membrane ranging from a serrated appearance in profile to total degradation in lysed hyphae. In some hyphae, almost all membrane systems including mitochondria, endoplasmic reticulum, and Golgi bodies, had changed drastically and in many cases formed membranous inclusions. Hyphae also contained electron-dense, bizarrely shaped structures that extended throughout. In the most inhibitory treatment, the hyphal wall was uneven in thickness, yet had N-acetyl-D-glucosamine label equal to that of the control, suggesting the irregular thickness of the wall was due to deposition of other polysaccharides.

A new non-protein enediyne antibiotic N1999A2: Unique enediyne chromophore similar to neocarzinostatin and DNA cleavage feature

The present NMR and X-ray structural studies demonstrated that the new antibiotic N1999A2 isolated from the broth filtrate of Streptomyces sp. AJ9493, possesses a novel 9-membered ring enediyne chromophore similar to neocarzinostatin, but is not chromoprotein. Of special interest is the fact that stable N1999A2 exists as enediyne chromophore alone as well as dynemicin A, esperamicin A 1 and calicheamicin γ 1. The major difference between N1999A2 and neocarzinostatin chromophore is lack of the amino sugar in N1999A2. The antibiotic N1999A2 revealed more random DNA cutting profile than neocarzinostatin chromophore.

Factors affecting membrane fouling in filtration of Saccharomyces cerevisiae in an internal ceramic filter bioreactor

Filtration of ethanol fermentation medium and broth by using symmetric and asymmetric ceramic membranes has been studied in an internal filter bioreactor. Factors studied included membrane structure and pore size, medium sterilization, and concentrations of glucose, yeast extract in the medium, yeast cell and protein in broth. The aim was to determine the main factors responsible for the decline in filtration performance during ethanol fermentation by Saccharomyces cerevisiae. Flux index (Fi) of a new concept has been developed to evaluate the degree of flux decline during the membrane fouling process. Fi was defined as the ratio of the membrane flux at certain filtration time (t = t) to the initial (t = −0) flux of pure water, not the initial (t = +0) flux of the test fluid. Flux with sterilized medium was approximately two-fold higher than that with unsterilized medium although the reason could not be explained clearly. Glucose, interaction between glucose and yeast extract, yeast cells, and proteins in fermentation broth were found to play an important part in membrane fouling. Fi of the symmetric membrane decreased to a less extent than that of the asymmetric membrane with increasing glucose concentration. But, the result with various yeast cell concentrations turned out to be contrary. Fouling was more serious for asymmetric membrane during the filtration of fermentation supernatant. This was thought to be due to different fouling mechanisms for the two types of membrane.

Formation of the Gel Layer of Polymers and Its Effect on the Permeation Flux in Crossflow Filtration of Corynebacterium glutamicum Broth

ABSTRACT The behavior of the permeation flux in crossflow filtration of Corynebacterium glutamicum broth was studied. In the beginning of filtration the permeation flux changed in accordance with the cake filtration model. The permeation flux agreed with the value calculated from the weight of the cell layer formed on the membrane per unit filtration area and the specific resistance of the cell layer measured in dead-end filtration. After cell deposition on the membrane, permeation resistance rapidly increased. The increase was due to the formation of the gel layer of the proteins and polysaccharides in the supernatant of the broth. When the circulation flow rate was raised, the weight of the cell layer reduced. However, the beginning of the rapid increase of permeation resistance came earlier and the apparent specific resistance of the cell layer increased. The higher the circulation flow rate, the higher the permeation flux at the beginning of the rapid increase of resistance. When the transmembrane pressure was lowered or the cell concentration was raised, the beginning of the rapid increase of the permeation resistance came earlier. The permeation flux at which the formation of the gel layer began was almost constant, even if the transmembrane pressure and the cell concentration were changed.

Antioxidative properties of extracts from Aspergillus candidus broth filtrate

This work evaluated the antioxidative properties of ethyl acetate extracts from Aspergillus candidus CCRC 31543 broth filtrate (EAEAC). EAEAC markedly exhibited antioxidative activity in a soybean oil peroxidation system as measured by the Rancimat method. This finding significantly correlated (r=0·9702, P<0·05) with the extent of antioxidative activity in a linoleic acid peroxidation system as measured by the thiocyanate method. EAEAC also displayed good thermal stability when heated at 185°C for 2 h. Although the antioxidative activity of the EAEAC was unstable at the alkali pH value, it was more effective at the neutral and acidic pH values. EAEAC had synergistic effects with α-tocopherol and citric acid in linoleic acid peroxidation system. EAEAC showed no mutagenicity to Salmonella typhimurium TA98 and TA100 as evaluated by Ames test. These properties indicated that Aspergillus candidus CCRC 31543 might be a potential antioxidant for application in food products. ©1997 SCI

Antioxidative properties of extracts fromAspergillus candidus broth filtrate

This work evaluated the antioxidative properties of ethyl acetate extracts from Aspergillus candidus CCRC 31543 broth filtrate (EAEAC). EAEAC markedly exhibited antioxidative activity in a soybean oil peroxidation system as measured by the Rancimat method. This finding significantly correlated (r=0·9702, P<0·05) with the extent of antioxidative activity in a linoleic acid peroxidation system as measured by the thiocyanate method. EAEAC also displayed good thermal stability when heated at 185°C for 2 h. Although the antioxidative activity of the EAEAC was unstable at the alkali pH value, it was more effective at the neutral and acidic pH values. EAEAC had synergistic effects with α-tocopherol and citric acid in linoleic acid peroxidation system. EAEAC showed no mutagenicity to Salmonella typhimurium TA98 and TA100 as evaluated by Ames test. These properties indicated that Aspergillus candidus CCRC 31543 might be a potential antioxidant for application in food products. ©1997 SCI

SNA-8073-B, a new isotetracenone antibiotic inhibits prolyl endopeptidase. I. Fermentation, isolation and biological properties.

SNA-8073-B, an inhibitor of prolyl endopeptidase isolated from the broth filtrate of Streptomyces sp. SNA-8073, is a new isotetracenone antibiotic. It was purified by ethyl acetate extraction, silica gel column chromatography and high performance liquid chromatography on ODS column. SNA-8073-B has the molecular formula of C20H16O5 and is a stereoisomer of SNA-8073-A (fujianmycin B, rubiginone A2). SNA-8073-B inhibited prolyl endopeptidase of Flavobacterium non-competitively (IC50 = 8.9 microM) when Z-Gly-Pro-pNA was used as a substrate, but SNA-8073-A did not show any inhibition even at 60 microM.

Antioxidant Activity of Extracts from Molds

The objective of this work was to screen molds for antioxidant activity. The results of screening 10 molds showed that three, Aspergillus candidus CCRC 31543, Aspergillus sp. CCRC 31742, and Penicillium oxalicum CCRC 31670, produce antioxidants that can be extracted from broth culture filtrates by ethyl acetate. The most antioxidant activity was found in the ethyl acetate extracts of A. candidus CCRC 31543. The antioxidant activity of A. candidus CCRC 31543 was as strong as that of rosemary extracts and butylated hydroxyanisole and was greater than that of α-tocopherol at the same concentrations. No antioxidant activity was found in aqueous extracts of A. candidus broth filtrate. A. candidus was cultured in a 500-ml Hiton flask containing 100 ml of growth broth, which consisted of 3% sucrose, 0.1 % yeast extract, 0.1 % polypeptone, 0.3% NaNO3, 0.1% K2HPO4, 0.05% MgSO4·· 7H2O, 0.05% KCl, and 0.001 % FeSO4 · 7H2O, at an incubation temperature of 25°C for 15 days, and a shaking rate of 130 rpm. The antioxidant activity of A. candidus reached a maximum level after 13 days of culture.

Effect of anaerobic digestion broth composition on membrane permeability

The effect of composition of anaerobic digestion (AD) broth on membrane permeability was explored through stirred-cell filtration of fractionated broths using various microfiltration (MF) and ultrafiltration (UF) membranes in order to provide insight into the membrane performance in the membrane bioreactor. In the filtration of original AD broth, the cake formation offered the highest hydraulic resistance to permeation but it led to greater rejection of volatile fatty acids. The fine colloids in the supernatant had the greatest responsibility for the cake layer resistance compared to other components in the broth, even though the quantity was relatively quite small. The flux behavior appeared to be irrelevant to the types of membranes used, but there was a pronounced discrepancy in the extent of fouling caused by adhesion and pore blocking. The extent of internal fouling for different membrane materials was evaluated in terms of surface free energy changes involved. The free energy of adhesion between substances in the broth and membrane surfaces was expressed as a function of the dispersion component of surface tension, which could explain why the fluoropolymer (PVDP) exhibited the lowest fouling tendency. The MF membrane with a pore size of 0.1 μm resulted in a minimal fouling tendency, suggesting that an optimal pore size exists due to the relationship between the sizes of membrane pore and broth constituents.

Conversion of Aflatoxin B1 by Humicola fuscoatra.

The conversion of aflatoxin B1 by six kinds of fungi, previously reported to assimilate aflatoxin B1, was investigated. The tested fungi were Aspergillus fumigatus, Paecilomyces lilacinus, P. inflatus, Humicola fuscoatra, Penicillium spinulosum, and Trichoderma aureoviride.After incubation at 25°C for 4 weeks, most of the tested fungi lowered the aflatoxin B1 level in the broth to less than 10% of the starting level. Penicillium spinulosum contained 80% of aflatoxin B1 in the mycelia, but the other fungi contained less than 30% of aflatoxin B1 in the mycelia. This fact suggests that aflatoxin B1 was converted by these 5 kinds of fungi.Only Humicola fuscoatra showed a marked difference in the aflatoxin conversion rate between intact and sterilized mycelia. Intact mycelia of the fungus degraded 90% of aflatoxin B1 but sterilized mycelia had no effect on aflatoxin B1. Aflatoxin B1 was converted in the mycelia of the fungus but not in the broth filtrate. These findings indicate that the conversion by Humicola fuscoatra was a biological reaction.The conversion products of aflatoxin B1 by Humicola fuscoatra were identified to be aflatoxicols A and B by TLC and HPLC, and all the reduced aflatoxin B1 was converted to aflatoxicols A and B.

Effect of anaerobic digestion broth composition on membrane permeability

The effect of composition of anaerobic digestion (AD) broth on membrane permeability was explored through stirred-cell filtration of fractionated broths using various microfiltraiion (MF) and ultrafiltration (UF) membranes in order to provide insight into the membrane performance in the membrane bioreactor. In the filtration of original AD broth, the cake formation offered the highest hydraulic resistance to permeation but it led to greater rejection of volatile fatty acids. The fine colloids in the supernatant had the greatest responsibility for the cake layer resistance compared to other components in the broth, even though the quantity was relatively quite small. The flux behavior appeared to be irrelevant to the types of membranes used, but there was a pronounced discrepancy in the extent of fouling caused by adhesion and pore blocking. The extent of internal fouling for different membrane materials was evaluated in terms of surface free energy changes involved. The free energy of adhesion between substances in the broth and membrane surfaces was expressed as a function of the dispersion component of surface tension, which could explain why the fluoropolymer (PVDP) exhibited the lowest fouling tendency. The MF membrane with a pore size of 0 1 µm resulted in a minimal fouling tendency, suggesting that an optimal pore size exists due to the relationship between the sizes of membrane pore and broth constituents.

Growth Suppression of Some Wood-Decay and Other Fungi by Bacillus subtilis

The antagonistic activity of an isolate of Bacillus subtilis was examined against five wood-decay fungi (Coriolus spp., Poria sp., Stereum sp., Hexagonia discopoda, and Schizophyllum commune) and five other fungi (Candida sp., Fusarium sp., Curvularia geniculata, Penicillium digitatum, and Trichoderma viride). The effect of the bacterium on the fungi was tested using aerated growth on potato dextrose agar, non-aerated (partially anaerobic) growth on potato dextrose agar, and growth in potato dextrose broth supplemented with cell-free filtrate of broth in which B. subtilis was previously cultured. All 10 fungal species were inhibited by water-soluble factors produced by the bacterium. Nine of the 10 species were adversely affected by volatiles synthesised by the bacterium. Varying degrees of inhibition were observed in the fungi in response to the presence of cell-free filtrate of B. subtilis in broth medium. The results of this study confirm the dual nature (production of antifungal volatile compounds in addition to water-soluble agents) of antagonism manifested by B. subtilis and the thermostable property of the antifungal factors it synthesises. It also broadens the range of fungi proven to be inhibited by the bacterium.

A screening method for antimitotic and antifungal substances using conidia of Pyricularia oryzae, modification and application to tropical marine fungi.

A bioassay method detecting deformations of mycelia germinated from conidia of Pyricularia oryzae P-2b, has been modified to give quantitative estimations. The method was first developed using antimitotic agents which showed characteristic curling effect. Morphological deformations include curling, swelling, hyper-divergency, beads shape and so on, and inhibition of the germination was also observed. For quantitative estimations, indices were introduced for the hyphal growth inhibition and a quantity of conidia in each assay cell and concentration of test solutions were adjusted. Details of the modified method and the application to screening assay of marine fungi isolated in Yap Islands are described. Eight strains of 109 tested showed morphological deformations, and chaetoglobosin A was isolated from the broth filtrate of a strain assigned to Chaetomium sp. This bioassay is a cheap, quick and easy method to be applied to the primary screening for antimitotic and antifungal substances from natural sources.

Growth of Staphylococcus aureus with Nafcillin In Vitro Induces -Toxin Production and Increases the Lethal Activity of Sterile Broth Filtrates in a Murine Model

The morbidity and mortality of Staphylococcus aureus infections remain high despite antibiotic therapy. To investigate further the observation that penicillins increase the hemolytic activity of staphylococcal cultures, 37 strains were grown in broth with and without subinhibitory nafcillin. Nafcillin stimulated hemolytic activity in nafcillin-susceptible and -resistant isolates. Sterile broth filtrates of nafcillin-associated cultures injected intraperitoneally in mice were more rapidly lethal than filtrates of the same strain grown without nafcillin. Lethality was neutralized by anti-alpha-toxin antisera. DNA-RNA hybridization revealed a nafcillin-associated increase in alpha-toxin mRNA during the postexponential growth phase after the activation of agr. Isolates grown in slightly inhibitory nafcillin concentrations had more alpha-toxin mRNA than did nafcillin-free cultures, whereas agr RNAIII levels were comparable. This suggests that nafcillin-induced alpha-toxin production is not entirely attributable to agr. A supplemental regulatory mechanism may be involved.

Optimum culture conditions for production of exfoliative toxin by Staphylococcus hyicus.

Optimum culture conditions for the production of exfoliative toxin by Staphylococcus hyicus (shET) were examined. High shET activity was obtained from the culture filtrate of HI and TY broth inoculated with S. hyicus. The pH in these two media ranged from 7 to 8.5 during bacterial culture, while the lowest pH in TS and BHI broth was less than 6. shET activity in the culture filtrate from TY broth inoculated with 10(7) CFU of S. hyicus per ml was higher than that in TY broth inoculated with 10(6) and 10(8) CFU of bacteria per ml. When shET activity in the culture filtrate was measured under various shaking conditions, the culture filtrate shaken at 75 oscillations per min had the highest shET activity of the five shaking conditions. shET activity of the culture filtrate of TY broth to which protease inhibitor had been added was the same as that of TY broth without inhibitor. shET activity in a shaking culture in an Erlenmeyer flask was also the same as that in sac culture and that in shaking culture using a shaking (Sakaguchi) flask. shET activity in TY broth supplemented with 100 mM glucose was significantly lower than that in TY broth without glucose. Based on the above results, the optimum culture conditions for the production of shET were as follows: inoculation of 3 x 10(9) CFU of S. hyicus strain P-1 into 300 ml of TY broth in a 2,000-ml Erlenmeyer flask, and incubation at 37 C with shaking at 75 oscillations per min.(ABSTRACT TRUNCATED AT 250 WORDS)

Synergistic extraction of penicillin G with aliphatic alcohols and butyl acetate

A solvent mixture of 1-hexanol and butyl acetate has been successfully used for the extraction of penicillin G. This solvent mixture may not only synergistically and effectively extract penicillin G, but also inhibit emulsion formation during the extraction of penicillin G from the filtrate of the fermentation broth. The equilibrium constants of the extraction, the molar ratios of 1-hexanol and penicillin G in the extracted species and the synergistic extraction of penicillin G have been studied by chemical analysis and by monitoring the absorbency shift in the FT-IR spectra of the functional groups in the solvents.

Influence of strain and medium composition on filtration of escherichia colisuspensions

Cross-flow filtration of Escherichia coli strains was examined at the laboratory and pilot scales using Romicon 500,000 molecular-weight-cutoff hollow fiber membranes. Both the series resistance and macrosolute polarization models were employed to compare performances. Total dissolved solids content above 90 g/L and viscosity above 1.1 x 10(-3) pac s of cell-free culture media were found to decrease average filtration fluxes by over 60% both in the absence and presence of cells. Broth filtration with culture media of dissolved solids levels below 80 g/L were influenced to a greater extent by harvest cell density. The collodial nature of the complex nutrient responsible for the total solids increase affected prediction of filtration performance. Differences in strain filterability were observed with JM109 preferred over DH5 in high solids-containing media and RR1 preferred over JM109 in low dissolved solids-containing media. Their research demonstrates the importance of cell strain and media selection in the performance of early downstream processing steps. (c) 1994 John Wiley & Sons, Inc.