Showing papers in "Applied Biochemistry and Biotechnology in 1995"
TL;DR: Toxicity assays need to be incorporated into the procedures used to monitor the effectiveness of PAH bioremediation, as much of the current PAH research focuses on techniques to enhance the bioavailability and, therefore, the degradation rates ofPAHs at polluted sites.
Abstract: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants, some of which are on the US Environmental Protection Agency priority pollutant list. Consequently, timely clean-up of contaminated sites is important. The lower-mol-wt PAHs are amenable to bioremediation; however, higher-mol-wt PAHs seem to be recalcitrant to microbial degradation. The rates of biodegradation of PAHs are highly variable and are dependent not only on PAH structure, but also on the physicochemical parameters of the site as well as the number and types of microorganisms present. PAHs sorb to organic matter in soils and sediments, and the rate of their desorption strongly influences the rate at which microorganisms can degrade the pollutants. Much of the current PAH research focuses on techniques to enhance the bioavailability and, therefore, the degradation rates of PAHs at polluted sites. Degradation products of PAHs are, however, not necessarily less toxic than the parent compounds. Therefore, toxicity assays need to be incorporated into the procedures used to monitor the effectiveness of PAH bioremediation. In addition, this article highlights areas of PAH research that require further investigation.
262 citations
TL;DR: In this article, the authors investigated the effect of fungal biomass on the metal uptake in the following decreasing preference pb>Cd>Ni, and found that the highest metal uptake was achieved by Picea engelmanii biomass with qmax = 351 mg Pb/gA.
Abstract: Native fungal biomass of fungiAbsidia orchidis, Penicillium chrysogenum, Rhizopus arrhizus, Rhizopus nigricans, and modified spruce sawdust (Picea engelmanii) sequestered metals in the following decreasing preference pb>Cd>Ni. The highest metal uptake was qmax = 351 mg Pb/gA. orchidis biomass. P.chrysogenum biomass could accumulate cadmium best at 56 mg Cd/g. The sorption of nickel was the weakest always at < 5 mg Ni/g. The spruce sawdust was modified by crosslinking, oxidation to acidic oxoforms, and by substitution. The highest metal uptake was observed in phosphorylated sawdust reaching qmax = 224 mg Pb/g, 56 mg Cd/g, and 26 mg Ni/g. The latter value is comparable to the value of nickel sorption by wet commercial resin Duolite GT-73. Some improvement in metal uptake was also observed after reinforcement of fungal biomass.
210 citations
170 citations
TL;DR: A quantitatively main molecular form ofCratylia mollis lectin, isoform 1 (iso 1) was purified by affinity chromatography on Sephadex G-75, followed by ion exchange chromatographyon CM-cellulose, and another lectin form was identified in the latter step.
Abstract: A quantitatively main molecular form ofCratylia mollis lectin, isoform 1 (iso 1) was purified by affinity chromatography on Sephadex G-75, followed by ion exchange chromatography on CM-cellulose. Another lectin form was identified in the latter step. Iso 1 is specific for glucose/mannose, with a main subunit of 31 kDa mol wt; the native protein is basic (pI 8.5-8.6) and the constituent polypeptides had a pI range of 5.15–7.75. An antibody to the protein was raised in a rabbit, and the conjugate was active in an immunosorbent assay.
157 citations
TL;DR: In this paper, conditions and acid strength of the phenol/sulfuric acid assay were investigated to improve agreement between absorbances obtained from different sugars, including xylose and fructose.
Abstract: The conditions and acid strength of the phenol/sulfuric acid assay were investigated to improve agreement between absorbances obtained from different sugars. It was found that by increasing acid strength and by cooling the tubes in water after a short reaction time, the values obtained for several sugars, including fructose and xylose, agreed, on an equimolar value, with that for glucose.
142 citations
TL;DR: This is the first report of microcapsules or microspheres containing biologically active material (DNA) being passed through the gastrointestinal tract, with the potential for substantial recovery.
Abstract: Calf thymus DNA was microencapsulated within crosslinked chitosan membranes, or immobilized within chitosan-coated alginate microspheres. Microcapsules were prepared by interfacial polymerization of chitosan, and alginate microspheres formed by emulsification/ internal gelation. Diameters ranged from 20 to 500 Μm, depending on the formulation conditions. Encapsulated DNA was quantifiedin situ by direct spectrophotometry (260 nm) and ethidium bromide fluorimetry, and compared to DNA measurements on the fractions following disruption and dissolution of the microspheres. Approximately 84% of the DNA was released upon core dissolution and membrane disruption, with 12% membrane bound. The yield of encapsulation was 96%. Leakage of DNA from intact microspheres/capsules was not observed. DNA microcapsules and microspheres were recovered intact from rat feces following gavage and gastrointestinal transit. Higher recoveries (60%) and reduced shrinkage during transit were obtained with the alginate microspheres. DNA was recovered and purified from the microcapsules and microspheres by chromatography and differential precipitation with ethanol. This is the first report of microcapsules or microspheres containing biologically active material (DNA) being passed through the gastrointestinal tract, with the potential for substantial recovery.
132 citations
TL;DR: An ammonia-based biomass pretreatment method named ammonia recycled percolation (ARP) process was investigated in this article, where a packed bed flowthrough-type reactor (percolation reactor) is used in recirculation mode.
Abstract: An ammonia-based biomass pretreatment method named ammonia recycled percolation (ARP) process was investigated. The process characteristics are:
1.
Aqueous ammonia is used as a pretreatment reagent;
2.
A packed bed flowthrough-type reactor (percolation reactor) is used in recirculation mode;
3.
ARP-Ammonia is continuously recycled.
118 citations
TL;DR: This study of cellulose conversion progress in batch mode indicates that during the early stage of SSF, cell growth is the rate-determining step in ethanol production, but at later times, and for most of the duration of the SSF process, enzymatic hydrolysis becomes the limiting factor.
Abstract: The cellulosic fraction of biomass feedstocks can be converted to ethanol, a promising alternative fuel, using the simultaneous saccharification and fermentation (SSF) process. This process integrates the enzymatic hydrolysis of cellulose to glucose with the fermentation of glucose to ethanol. Its performance depends on the characteristics of the biomass, the quality of the cellulase enzyme complex, and the behavior of the fermentative organism. This study of cellulose conversion progress in batch mode indicates that during the early stage of SSF, cell growth is the rate-determining step in ethanol production. At later times, however, and for most of the duration of the SSF process, enzymatic hydrolysis becomes the limiting factor. Further experimental probing has shown that cellulose accessibility to the enzyme is the key cause of the decreased rate of cellulose hydrolysis. It is therefore concluded that accessibility needs to be enhanced to improve the productivity of the SSF process.
99 citations
TL;DR: In this article, the production of extracellular polysaccharides from carob pod extract by Aureobasidium pullulans in batch fermentation was investigated, and the highest values of pullulan proportion and fermentation efficiency were assumed at initial sugar concentration of 25 g/L, pH 6.5 and 30°C.
Abstract: The production of extracellular polysaccharides from carob pod extract by Aureobasidium pullulans in batch fermentation was investigated. Optimum conditions for polysaccharide productivity, polysaccharide yield, and fermentation efficiency were: initial sugar concentration of 25 g/L, initial pH 6.5, and temperature 25–30°C. A maximum polysaccharide concentration (6.5 g/L), polysaccharide productivity (2.16 g/L/d), total biomass concentration (6.3 g/L), and polysaccharide yield (30%) were obtained with inoculum at 10% (v/v), initial sugars in carob pod extract of 25 g/L, pH 6.5, and 25°C. The highest values of pullulan proportion (70% of total polysaccharides) and fermentation efficiency (89%) were assumed at initial sugar concentration of 25 g/L, pH 6.5 and 30°C. Structural characterization of purified pullulan samples by monosaccharide and methylation analyses, 13C-NMR, and pullulanase digestion combined with size-exclusion chromatography revealed the presence of mainly α-(l → 4) (68%) and α-(l → 6) (31%) glucosidic linkages; however, small amounts (<1%) of triply linked (1, 3, 4-and 1, 4, 6-Glc) glucose residues were detected. The molecularsize distribution and intrinsic viscosity of pullulan derived from culture grown at pH 4.5 (30°C) showed a higher molecular weight than its counterpart obtained at pH 6.5 (30°C).
95 citations
TL;DR: In this paper, switchgrass and coastal bermudagrass were pretreated by ammonia fiber explosion (AFEX), and the treated materials hydrolyzed using 5 IU cellulase/g substrate.
Abstract: Switchgrass and coastal bermudagrass were pretreated by ammonia fiber explosion (AFEX), and the treated materials hydrolyzed using 5 IU cellulase/g substrate. Resulting sugar solutions (2–3%, w/v) were fermented with recombinantKlebsiella oxytoca. Glucose was rapidly and completely fermented to ethanol, whereas xylose fermentation was slower and less complete. At higher sugar concentrations (≈8%) glucose fermentation continued, but xylose fermentation almost ceased. Protein extraction somewhat enhanced ethanol production from coastal bermudagrass. Improved fermentation technologies and media appear necessary for practical mixed-sugar lignocellulosic hydrolyzates.
90 citations
TL;DR: The scope of this work is to review the state of the art in bioprocessing technologies pertinent to the secondary metabolite production from suspension cultures of callus cells for large-scale production of natural compounds.
Abstract: Considering various forms of in vitro plant tissue cultures, cell suspension culture is most amenable to large-scale production of natural compounds, owing primarily to its superior culture homogeneity. This fact has already been demonstrated in several largescale applications, including the commercial shikonin process. The scope of this work is to review the state of the art in bioprocessing technologies pertinent to the secondary metabolite production from suspension cultures of callus cells. In the first part of the review, plant cell physiology relevant to bioprocess design is considered. This is followed by an in-depth discussion on the bioreactor design and operation and its effect on plant cell suspension cultures. Finally, recent commercial exploitation and development are summarized. Following the review, related patents and literature are listed.
TL;DR: PEG molecular weight strongly affects the enzyme partition coefficient, whereas pH variation from 5.5 to 8.0 has little effect, and the addition of sodium chloride to a PEG 1540/phosphate system raises the peroxidase partition coefficient 13.5-fold without important changes in that of total horseradish root proteins.
Abstract: The effect of poly(ethyleneglycol) (PEG) molecular weight, system pH, and sodium chloride concentration on the partitioning behavior of horseradish peroxidase fromArmomcia rusticana root extract was investigated in poly(ethyleneglycol)/sodium phosphate systems. PEG molecular weight strongly affects the enzyme partition coefficient, whereas pH variation from 5.5 to 8.0 has little effect. The addition of sodium chloride (8% w/w) to a PEG 1540/phosphate system, pH 7.0, raises the peroxidase partition coefficient 13.5-fold without important changes in that of total horseradish root proteins. Moreover, these conditions allow direct homogenization of theA. rusticana roots with the selected aqueous two-phase system with the clear top phase containing over 90% of the enzyme and the purification factor being 4.8.
TL;DR: In this paper, the catalase (from Aspergillus niger) has been immobilized by a chemical method on the pous SiO2 modified with γ-aminopropyltrietoxysilane, followed with glutaraldehyde and by a physical method in alginate and carrageenan gel.
Abstract: The catalase (fromAspergillus niger) has been immobilized by a chemical method on the pous SiO2 modified with γ-aminopropyltrietoxysilane, followed with glutaraldehyde and by a physical method in alginate and γ-carrageenan gel. Optimum support:enzyme ratios and pH values were determined for modified SiO2 in a series of immobilization reactions of catalase in the presence of the crosslinking agent glutaraldehyde, and for alginate and γ-carrageenan in the presence of hemoglobin and bovine serum albimine. pH and temperaturedependent activity variations and the stability properties of immobilized catalase preparations were investigated. Rate constants for H2O2 decomposition and catalase deactivation were determined. The decomposition rate of H2O2 used in the cold pasteurizatioan of milk were investigated in a discontinuous batch type reactor system. Activity half-lives of immobilized catalase were determined.
TL;DR: In this article, the authors used the same pellets by transferring them into fresh media every time when the glucose was exhausted over a period of 22 d yielded 1742 or 2001 g/L lactic acid total, depending on the media used.
Abstract: Rhizopus oryzae NRRL 395 produces optically pureL(+)-lactic acid that is highly preferred for the production of environmentally benign polymers. With xylose as the carbon source for cultivation, it can be self-immobilized as pellets with a size of about 1mm. Repeated usage of the same pellets by transferring them into fresh media every time when the glucose was exhausted over a period of 22 d yielded 1742 or 2001 g/L lactic acid total (based on 100-mL working volume) depending on the media used. Lactic acid is known to be a strong inhibitor for both growth and production, and it can be removed continuously by the adsorption on the PVP resin. With the fermenter-adsorber system, the fermentation can be performed as effectively as the ones with added neutralizing agents, such as calcium carbonate and sodium hydroxide. One problem of the fermenter-adsorber system is that lower production was obtained than in shake flasks; hence, proper reactor design is necessary to improve the process.
TL;DR: A recombinant cutinase from Fusarium solani was encapsulated in AOT reversed micelles and Physicochemical parameters of the system were optimized relative to triolein hydrolysis.
Abstract: A recombinant cutinase fromFusarium solani was encapsulated in AOT reversed micelles. Physicochemical parameters of the system were optimized relative to triolein hydrolysis. Kinetic studies of triglyceride hydrolysis showed a decrease in specificity with increase of the acyl chain length. Stability of cutinase in the system under study is lower than in aqueous solution and decreases with increase in the water content in the system (W0 = [H2O]/[AOT]). The products of triolein hydrolysis had little effect on the cutinase stability. Although glycerol did not alter the stability, oleic acid decreases the enzyme stability. The increase in log P of solvent (fromiso-octane ton-dodecane) decreased the stability. Deactivation profiles were fitted with the Henley and Sadana model (1).
TL;DR: In this article, the formation of a zinc-cellulose complex during the pretreatment of cellulose improves the yield of glucose in both the enzymatic and acid hydrolysis of celluloses.
Abstract: The efficient conversion of cellulosic materials to ethanol has been hindered by the low yield of sugars, the high energy consumption in pretreatment processes, and the difficulty of recycling the pretreatment agents. Zinc chloride may provide an alternative for pretreating biomass prior to the hydrolysis of cellulose. The formation of a zinc-cellulose complex during the pretreatment of cellulose improves the yield of glucose in both the enzymatic and acid hydrolysis of cellulose. Low-temperature acid hydrolysis of cellulose in zinc chloride solution is carried out in two stages, a liquefaction stage and a saccharification stage. Because of the formation of zinc-cellulose complex in the first stage, the required amount of acid in the second stage has been decreased significantly. In 67% zinc chloride solution, a 99.5% yield of soluble sugars has been obtained at 70°C and 0.5M acid concentration. The ratio of zinc chloride to cellulose has been reduced from 4.5 to 1.5, and the yield of soluble sugars is kept above 80%. The rate of hydrolysis is affected by the ratio of zinc chloride to cellulose, acid concentration, and temperature.
TL;DR: In this paper, the effect of chemical and physical factors on solution viscosity was studied, and the V2-7 EPS showed pseudoplastic behavior at concentrations over 0.5% w/v.
Abstract: Volcaniella eurihalina strain F2-7 synthesizes an exopolysaccharide named V2-7, primarily composed of glucose, mannose, and rhamnose. The effect of chemical and physical factors on solution viscosity was studied. The V2-7 EPS showed pseudoplastic behavior at concentrations over 0.5% w/v. Viscosity decreased with temperature, but the viscosity values were restored after cooling. Freeze-thawing treatment did not affect the rheological properties of its solutions. Addition of inorganic salts produced a diminution of viscosity. However, the most remarkable aspect of V2-7 EPS is the effect of pH on its solutions; it is able to form high viscosity solutions, like a gel, at low pH values even in the presence of inorganic salts. This property, not present in neutral and alkaline solutions, makes it potentially useful for various industrial applications.
TL;DR: The conversion of monosaccharides in organe peel hydrolysates to ethanol by recombinantEscherichia coli KO11 has been investigated in pH-controlled batch fermentations at 32 and 37°C and appears to be optimal.
Abstract: The conversion of monosaccharides in orange peel hydrolysates to ethanol by recombinant Escherichia coli KO11 has been investigated in pH-controlled batch fermentations at 32 and 37 degrees C. pH values and concentration of peel hydrolysate were varied to determine approximate optimal conditions and limitations of these fermentations. Very high yields of ethanol were achieved by this microorganism at reasonable ethanol concentrations (28-48 g/L). The pH range between 5.8 and 6.2 appears to be optimal. The microorganism can convert all major monosaccharides in orange peel hydrolysates to ethanol and to smaller amounts of acetic and lactic acids. Acetic acid is coproduced in equimolar amounts with ethanol by catabolism of salts of galacturonic acid.
TL;DR: It is proposed that the suspended-cell bioreactor is the method of choice and that plant cells respond to fluid forces differently from their animal cell counterparts in bioreactors, and that the plant cell’s sublytic responses to fluid force can be used advantageously in stirred suspension cultures.
Abstract: Plant cells are a source of pharmaceuticals, fragrances, flavors, and dyes that are traditionally produced by extraction of tissues from whole plants. Recent trends in plant product research, transformed cell lines, and conservation policies place increased demand on plant cell culture technology. Unlike processing of microbial and animal cells in bioreactors, no economically viable process based on the suspension culture of plant cells in bioreactors has yet been possible in North America. It is proposed that the suspended-cell bioreactor is the method of choice and that plant cells respond to fluid forces (defined as laminar shear and turbulent eddies-based and bubble-based forces) differently from their animal cell counterparts in bioreactors. Although plant cells produce a tough cell wall, fluid forces, although not lethal within normal range, impact the membrane transport processes and metabolic function of plant cells; these effects are termed sublytic. Previous approaches to shear sensitivity of plant cells are reviewed in the context of these sublytic effects. A model for systematic evaluation of fluid-mechanical causes and physiological mechanisms behind sublytic effects is proposed. It is further proposed that, once understood, the plant cell’s sublytic responses to fluid force can be used advantageously in stirred suspension cultures.
TL;DR: The suitability of the anaerobic digestion residues as a soil amendment was evaluated through extensive chemical analysis and greenhouse studies using corn as an indicator crop as discussed by the authors, and native Samoan soil was used to evaluate the specific application rates for the compost.
Abstract: Tuna processing wastes (sludges high in fat, oil, and grease [FOG]) and municipal solid waste (MSW) generated on Tutuila Island, American Samoa, represent an ongoing disposal challenge. The biological conversion of the organic fraction of these wastes to useful products, including methane and fertilizer-grade residue, through anaerobic high-solids digestion is currently in scale-up development. The suitability of the anaerobic digestion residues as a soil amendment was evaluated through extensive chemical analysis and greenhouse studies using corn as an indicator crop. Additionally, native Samoan soil was used to evaluate the specific application rates for the compost. Experiments established that anaerobic residues increase crop yields in direct proportion to increases in the application rate. Additionally, nutrient saturation was not demonstrated within the range of application rates evaluated for the Samoan soil. Beyond nutrient supplementation, organic residue amendment to Samoan soil imparts enhanced water- and nutrient-binding capacities.
TL;DR: By increasing the initial phosphate concentration in the medium in the range of 0–1.25 mM, both the cell growth and the saponin accumulation were greatly improved, and the utilization of sugar and nitrogen sources was also increased.
Abstract: Effects of initial phosphate concentration on the growth, ginsenoside saponin production, and the consumption of sugar and nitrogen sources by suspended cells ofPanax notoginseng (Burk) F. H. Chen were investigated in a 250-mL shake flask. The results indicate that by increasing the initial phosphate concentration in the medium in the range of 0–1.25 mM, both the cell growth and the saponin accumulation were greatly improved, and the utilization of sugar and nitrogen sources was also increased. The highest production, productivity, and yield of ginsenosides obtained were 0.98 g/L, 45.5 mg/L/d, and 0.030 g/g at 1.25 mM of initial medium phosphate. At a relatively higher level of medium phosphate, i.e., 2.0 mM, the product accumulation was inhibited to some degree, although the cell growth was not.
TL;DR: The potentiality of treatments with NH4OH solutions for improving the quality of protein concentrates from Candida utilis biomass was studied and under selected conditions, 96% of nucleic acid removal was achieved with 88% protein recovery.
Abstract: The potentiality of treatments with NH4OH solutions for improving the quality of protein concentrates fromCandida utilis biomass was studied. The effects of NH4OH concentration, reaction time, and temperature on both biomass recovery and composition of processed samples (including nucleic acid and protein contents) were studied. The results obtained were used to develop empirical models providing a quantitative interpretation of the interrelationships among the variables involved. Additional discussion of the reaction selectivity is provided. Under selected conditions, 96% of nucleic acid removal was achieved with 88% protein recovery. The treated cells were high in vitro digestibility and showed an amino acid profile similar to that of untreated biomass.
TL;DR: The analytical utility of NIR spectroscopy for monitoring glucose and glutamine levels in mammalian and insect cell cultures is demonstrated and the best overall analytical performance is obtained by combining Fourier filtering and PLS regression.
Abstract: A method is described for measuring the concentrations of both glucose and glutamine in binary mixtures from near infrared (NIR) absorption spectra. Spectra are collected over the range from 5000–4000/cm (2.0–2.5μm) with a 1-mm optical path length. Glucose absorbance features at 4710, 4400, and 4300/cm and glutamine features at 4700, 4580, and 4390/cm provide the analytical information required for the measurement. Multivariate calibration models are generated by using partial least squares (PLS) regression alone and PLS regression combined with a preprocessing digital Fourier filtering step. The ideal number of PLS factors and spectral range are identified separately for each analyte. In addition, the optimum Fourier filter parameters are established for both compounds. The best overall analytical performance is obtained by combining Fourier filtering and PLS regression. Glucose measurements are established over the concentration range from 1.66–59.91 mM, with a standard error of prediction (SEP) of 0.32 mM and a mean percent error of 1.84%. Glutamine can be measured over the concentration range from 1.10–30.65 mM with a SEP of 0.75 mM and a mean percent error of 6.67%. These results demonstrate the analytical utility of NIR spectroscopy for monitoring glucose and glutamine levels in mammalian and insect cell cultures.
TL;DR: The technical feasibility of using agricultural wastes (mango and date industry wastes) as a substrate for the cultivation of Pleurotus ostreatus NRRL-0366 is evaluated and the highest yield of fruiting bodies was obtained using a mixture of date waste and rice straw at a ratio (1:1).
Abstract: The technical feasibility of using agricultural wastes (mango and date industry wastes) as a substrate for the cultivation ofPleurotus ostreatus NRRL-0366 is evaluated When comparing the biological efficiency of mushroom production, the highest yield of fruiting bodies was obtained using a mixture of date waste and rice straw at a ratio (1:1) (1196%), followed by a mixture 3:1 (1116%) The lowest one was the mixture 2:1 (919%) FungusPleurotus ostreatus NRRL-0366 can also be cultivated on mango waste supplemented with rice straw at a different ratio The best one was the 1:1 mixture (1018%), whereas the lowest was a mixture 3:1 (64%) Comparing the results obtained favored the use of date waste as a substrate for growingPleurotus ostreatus NRRL-0366 Spawn was cultured on three different substrates as follows: Date waste alone (I); 1:1 (by wt) date waste and rice straw (II); 1:1:1 date waste, rice straw, and corncobs (III) Final dry weight and composition of the fruiting bodies are tabulated for the three sets of conditions Date waste and rice straw mixture (II) is a good source of nonstarchy carbohydrate (67%) and protein (2744%) containing amounts of essential amino acids, especially lysine and low RNA (381%) Elemental analysis were studied in the fruit bodies of the three media
TL;DR: An anaerobic bioremediation process for the degradation of nitroaromatic compounds in soil was demonstrated in this article, where a bioreactor was loaded with approx 23 m3 of TNT-contaminated soil in the form of a 50∶50 soil: water slurry.
Abstract: An anaerobic bioremediation process for the degradation of nitroaromatic compounds in soil was demonstrated. Thisex situ process was demonstrated full-scale at a 2,4,6-trinitrotoluene (TNT)-contaminated site near Weldon Spring, MO. A bioreactor was loaded with approx 23 m3 of TNT-contaminated soil in the form of a 50∶50 soil: water slurry. This slurry was augmented with a starchy carbon source (1–2% w/v) and buffered with phosphate to near-neutral pH. Indigenous soil bacteria utilized the oxygen, making the slurry anaerobic within 1–2 d. Anaerobes then degraded the TNT (3000 mg/kg) in approx 11 wk. A relatively long treatment time for the bioremediation of the TNT-contaminated soil was necessary, possibly because of the cool ambient temperatures, high clay content of the soil, high level of contamination, and high level of recalcitrance of TNT in soils.
TL;DR: The main purpose of this work was to find the optimal conditions of agitation and aeration for the growth of Aspergillus niger and production of gluconic acid in submerged culture in a batch fermentor at a bench-top scale.
Abstract: The effects of agitation and aeration in the production of gluconic acid by Aspergillus niger from a glucose medium were investigated. Experiments were conducted at aeration rates of 5.0 and 10.0 L/min. Four different agitation speeds were investigated for each aeration rate. Gluconic acid concentration and biomass concentration were analyzed, and the rate of consumption of substrate by A. niger was noted. The main purpose of this work was to find the optimal conditions of agitation and aeration for the growth of A. niger and production of gluconic acid in submerged culture in a batch fermentor at a bench-top scale. The oxygen-transfer rates at different agitation and aeration rates were calculated. The gluconic acid concentration and rate of growth of A. niger increased with increase in the agitation and aeration rates.
TL;DR: In this paper, the authors used the technique of isoelectric focusing (IEF) to study the iso- or multi-enzyme distribution for LAO activity in the B cotiara snake venom.
Abstract: Toxins, enzymes, and biologically active peptides are the main components of snake venoms from the genus Bothrops Following the venom inoculation, the local effects are hemorrhage, edema, and myonecrosis Nineteen different species of Brazilian Bothrops were screened for protein content and L-amino acid oxidase activity B cotiara, formerly found in the South of Brazil, is now threatened with extinction Its venom contains a highly hemorrhagic fraction and, as expected from the deep yellow color of the corresponding lyophilized powder, a high L-amino acid oxidase (LAO) activity was also characterized Flavin adenine dinucleotide (FAD) is its associate coenzyme B cotiara venom LAO catalyzed the oxidative deamination of several L-amino acids, and the best substrates were methionine, leucine, tryptophan, and phenylalanine, hence, its potential application for the use of biosensors for aspartame determination and for the removal of amino acids from plasma High levels for LAO were also found in other species than B cotiara In addition, the technique of isoelectric focusing (IEF) was employed as a powerful tool to study the iso- or multi-enzyme distribution for LAO activity in the B cotiara snake venom
TL;DR: The objective is to develop biocatalysts for the rapid and efficient conversion of xylose by engineering key metabolic pathways in selected organisms by surveying several industrial microorganisms according to several primary traits considered to be essential, as well as a number of secondary traits thought to be desirable, in a commercial biomass-to-ethanol process.
Abstract: An economical biomass-to-ethanol process depends on the efficient conversion of both its cellulose and hemicellulose components. On a dry weight basis, the typical feedstock contains approx 25-50% (w/w) glucose, 10-30% (w/w) xylose, 15-30% (w/w) lignin, and 1-5% (w/w) of other minor pentose and hexose sugars. Although many microorganisms can ferment the glucose component in cellulose to ethanol, conversion of pentose sugars in the hemicellulose fraction, particularly xylose, has been hindered by the lack of a suitable biocatalyst. Despite the development of recombinant strains with improved fermentation performance, increased ethanol yields and concentrations and shorter fermentation times are key targets that have yet to be achieved from lignocellulosic hydrolyzates. Our objective is to develop biocatalysts for the rapid and efficient conversion of xylose by engineering key metabolic pathways in selected organisms. To identify promising biocatalysts for these efforts, we have surveyed several industrial microorganisms according to several primary traits considered to be essential, as well as a number of secondary traits considered to be desirable, in a commercial biomass-to-ethanol process.
TL;DR: The primary enzymatic activity that caused the removal of the oligosaccharide residues of avidin appeared to be similar to endoglycosidase F. meningosepticum.
Abstract: A simple procedure for the preparation of deglycosylated avidin is described. Commercially obtained avidin was treated with a mixed microbial culture. The cells were capable of growing on the oligosaccharide residues, but generally ignored the polypeptide portion of the egg white glycoprotein. The resultant deglycosylated avidin retained its biotin-binding characteristics. The major bacterial strain (strain BECH080), responsible for the deglycosylation, was isolated. On the basis of elementary biochemical tests, fatty acid, and phenotypic analyses, the isolate was identified as a strain ofFlavobacterium meningosepticum. The primary enzymatic activity that caused the removal of the oligosaccharide residues of avidin appeared to be similar to endoglycosidase F.
TL;DR: A complete process for the production and purification of succinic acid from carbohydrates has been developed in this paper, which includes fermentation, desalting electrodialysis, water splitting and crystallization.
Abstract: Succinic acid is a versatile four-carbon dicarboxylic acid. It can be used commerically as an intermediate chemical for the manufacture of 1,4-butanediol, maleic anhydride, and many other chemicals. Succinic acid can be produced by the fermentation of carbohydrates. A complete process for the production and purification of succinic acid from carbohydrates has been developed. The process includes fermentation, desalting electrodialysis, water-splitting electrodialysis, and crystallization to produce a pure crystalline succinic acid. This article will present experimental work performed in the development of this process.