bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxygen mass transfer and gas holdup in a bubble column bioreactor with biosynthesis liquids
Authors: Gavrilescu M. , Roman R. V.
Published: December 2004

The influence of the rheology of some antibiotic biosynthesis liquids produced by Streptomyces aureofaciens, Nocardia mediterranei and Penicillium chrysogenum on the volumetric liquid phase oxygen transfer coefficient, kLa, and gas holdup, εG, together with the influence of superficial gas velocity, were studied in a bubble column bioreactor, using samples of fermentation liquids taken from industrial stirred tank fermenters, at 30‐hour intervals during fermentation batch.

The results were compared to those of previous studies from literature on non‐Newtonian homogeneous fluids, such as CMC‐Na, xanthan and starch solutions, respectively.

In the heterogeneous broths, εG and kLa decreased with increasing apparent viscosity of the broth and increased with increasing superficial velocity.

The experimental data were correlated using non‐linear regression

with correlation coefficients above 0.85.
Characteristics of phytase produced by Aspergillus carbonarius NRC 401121 in canola meal
Authors: Al‐Asheh S. , Duvnjak Z.
Published: December 2004

Aspergillus carbonarius NRC 401121 phytase was produced on canola meal in a solid‐state fermentation process. A Km value of 0.345 mM and a vmax of 0.81 units were determined for sodium phytate. The optimum pH and temperature were 4.7 and 53°C, respectively. Activation of the enzyme occurred when it was preincubated at higher temperatures for a period of time. The energy of activation, the entropy and the enthalpy changes were evaluated to be 7,800 cal/mole, 74 cal/(mole · K) and 24,000 cal/mole for this enzyme, respectively.

The effect of time and the extractant: solid state culture ratio upon the single step extraction of phytase from a solid‐state culture were evaluated.

Mathematical correlations which fit the experimental data reasonably well were proposed for some of the studied processes.
Influence of the casing on the microflora of compost colonized by Agaricus bisporus
Authors: Gillmann L. , Lebeault J. M. , Cochet N.
Published: December 2004

The role of the casing soil during mushroom cultivation was studied with respect to the composition of the microflora. The thermophilic bacteria became more numerous and the number of mesophiles was clearly enhanced. The casing soil had a protective action against antagonistic microflora. Interactions between the microflora and the mushroom were also studied.

Moreover, lignocellulose degradation was evaluated by enzymatic measurements during cultivation and process, and was documented by an ultrastructural study.
Enzymatic modification of yeast protein isolates
Authors: Einhorn‐Stoll U. , Kretzschmar U. , Lippert E.
Published: December 2004

Yeast protein isolate with 85% of pure protein and 1.2% of nucleic acids in dry matter was isolated fromSaccharomyces cerevisiaeby a procedure of two pre‐treatment steps, acidic extraction and isoelectric precipitation. The application of this yeast protein isolate was limited by its functionality resulting from the partially extreme isolating conditions.

An enzymatic partial hydrolysis with Thermitase to a degree of hydrolysis of 5% not only improved the solubility and foaming properties, but also the water binding capacity and the emulsifying properties. The hydrolysate was free of bitter taste and could be applied either in two fractions of different solubility after centrifugation or as a whole product in food systems to improve the physiological and functional quality. The yeast protein hydrolysate had the same or even better properties than conventional protein products.
Intensification of transfer processes in biotechnology and chemical engineering using static mixers. (Review)
Authors: Gavrilescu M. , Tudose R. Z.
Published: December 2004

A review of the intensification of moment, mass and heat transfer using an “unconventional” method, namely the application of static mixers, also known as “motionless mixers”, is presented in this paper.

After the presentation of some structural types of static mixers, studies with particular emphasis on flow behaviour, pressure drop, mixing, mass and, heat transfer in the presence of static mixing devices, used in biotechnology and chemical engineering, were discussed.

The suitability of static mixers to enhance the transfer process parameters was also justified by the low energy requirement, while the fluids might have different viscosities and because of this fact they could remove any mistakes made by the equipment.

The article is not directed towards a comprehensive review, but it should serve as a landmark in future undertakings.
Behaviour of different Lactobacillus species in the production of lactic acid by the fermentation of whey
Authors: Rincón J. , Fuertes J. , Rodríguez L. , Monteagudo J. M.
Published: December 2004

The behaviour of different Lactobacillus casei and Lactobacillus plantarum species in the fermentation of Manchego whey was experimentally studied and the results were statistically analyzed using a hypothesis contrast method. The steadiness of the velocity of the production of lactic acid during the fermentation process allowed the use of this variable to compare the different microorganisms. From this comparison it was inferred that the individuals of the same population behave alike and that the L. casei population produces lactic acid at a higher rate than the L. plantarum population. A competitive effect among the members of the L. casei population was also observed.
“Macroscopic pattern analysis” based on formal analogies as a scientific methodology for complex systems
Authors: Moser A.
Published: December 2004

Bioprocess engineering at present concentrates on the enormous problems in the environment. What is therefore needed is a sound methodology, which should be based on the interactions between the physiology of biological reaction networks and physical processes in the environment and which should be an analogy to bioreactor performance. The conventional methodology is empirically oriented, using pilot plant data for the experimental estimates of process economics, where all further details are elucidated following the mechanistic approach on the microscopic level based on assumed mechanisms (causalities). According to the new view, the new systems‐based methodology uses mathematical models as approximations and includes all the interactions. Pilot plant data are needed for model falsification, using analogies on the formal macroscopic level. Bioreactor scale‐up as one application is a more rapid procedure of reasonable accuracy, where both the biokinetics as well as the fluid dynamics are quantified using formal macroscopic analogies.

Model consistency and plausibility are the basic criteria when using model computer simulations as a decisive aid, while experiments lose their central role and are on longer the basis for evaluating the scientific work; they are simply the basis of the researcher's intuition. Another typical feature of complex systems is that model parameters are interdependent. The final decisive fact will be the mental experiment (“thinking” with the left and right side of the brain), which can be supported using computer simulations. This evolutionary interplay between the three realities of thinking, experimenting and simulating leads to a holistic progress towards the better understanding of highly complex systems. It offers the solution to the problems, which is needed in future.
Studies on the root nodules of leguminous plants: The production of indole acetic acid in culture by a Rhizobium sp. from a leguminous climbing shrub Derris scandens benth
Authors: De P. S. , Basu P. S.
Published: December 2004

The Rhizobium sp. When isolated form the root nodules of a leguminous climbing shrub Derris scandens produced a high amount of indole acetic acid (IAA) (135.2 μg/ml) from the tryptophan‐supple‐mented basal medium. Growth and IAA production started simultaneously, and the maximum amount of IAA was produced as a secondary metabolite in the stationary phase of growth. The IAA production by the Rhizobium sp. was increased by 503% when the medium was supplemented with mannitol (2%), KNO3 (0.2%), nicotinic acid (0.1 μg/ml) and MnSO4 (1 μg/ml) in addition to tryptophan (4 mg/ml)/

The possible role of the rhizobial production of IAA on the rhizobia‐legume symbiosis is also discussed.
Effect of oleic acid on the production of ethanol and fructose from glucose/fructose mixtures in an immobilized cell reactor
Authors: Guénette M. E. , Duvnjak Z.
Published: December 2004

Saccharomyces cerevisiae ATCC 39859 was immobilized onto small cubes of wood to produce ethanol and very enriched fructose syrup from glucose/fructose mixtures through the selective fermentation of glucose. A maximum ethanol productivity of 21.9 g/l‐h was attained from a feed containing 9.7% (w/v) glucose and 9.9% (w/v) fructose. An ethanol concentration, glucose conversion and fructose yield of 29.6 g/l, 62% and 99% were obtained, respectively. This resulted in a final fructose/glucose ratio of 2.7. At lower ethanol productivity levels the fructose/glucose ratio increases, as does the ethanol concentration in the effluent. The addition of 30 mg/l oleic acid to the medium increased the ethanol productivity and its concentration by 13% at a dilution rate of 0.74 h−1.
Media for the detection of Bacillus larvae spores in honey
Authors: Steinkraus K. H. , Morse R. A.
Published: December 2004

Bacillus larvae, the causative agent of American foulbrood in honey bees completes its life cycle of germination, outgrowth and sporulation in young honey bee larvae by killing them and often bringing about the destruction of the entire hive. While B. larvae germinates and outgrows on complex organic media in vitro, the literature suggests, for reasons that are not at all clear, that a relatively large number of spores of B. larvae are required to yield each visible colony (colony forming units, CFU) on media. Various researchers have reported that from 16 to 3,000 or more spores of B. larvae are required to yield a single colony on an agar plate. HANSEN in Denmark designed a useful method of spreading approximately 80 mg of honey directly on the surface of a PETRI plate containing “J” agar medium to determine if B. larvae spores are present in the honey. In the present study, selected media were tested for the ability to recover B. larvae spores in honeys in the form of visible colonies (CFU) using HANSEN's strek method. A modification of a medium (TMYGP) developed by DINGMAN and STAHLY, (T‐HCL‐YGP agar), recovered considerably more viable B. larvae spores in the form of visible colonies (CFU) than HANSEN's “J” medium. When “J” medium was fortified with 0.1% sodium pyruvate, it was comparable to modified T‐HCL‐YGP medium in its recovery of B. larvae spores. Brain heart infusion agar (BHIA) with the addition of thiamine recovered more spores in the form of viable colonies than did “J” medium but it was not as efficient as T‐HCL‐YGP medium. Serial dilution from 100 to 10,000 times of weighed samples of honey with deionized water led to higher spore counts (CFU per g honey) than that indicated by undiluted honeys plated at 80 mg levels directly onto the surface of media by the HANSEN procedure.
Production of citrinin by Monascus ruber submerged culture in chemically defined media
Authors: Pastrana L. , Loret M. O. , Blanc P. J. , Goma G.
Published: December 2004

Following our investigations on citrinin production by Monascus ruber in a chemically defined medium, the kinetic behaviour of this toxin in the fermenter was studied with relation to production of pigments, biomass and nutrient consumption. Showing a secondary metabolite pattern, citrinin was produced when dμ/dt and dQs/dt were ≤ 0, while a high specific production rate of pigments occurred when dμ/dt and dQs/dt were > 0. No trophophase‐idiophase transition was detected during the cuitivation, and the behaviour of pigment production was similar to that of a primary metabolite.
Sucrose medium osmolality as a regulator of anabolic and catabolic parameters in Zymomonas culture
Authors: Vigants A. , Zikmanis P. , Bekers M.
Published: December 2004

This study focuses on the growth of Zymomonas mobilis strain 113 S and its ethanol and levan production under the conditions of increasing sucrose medium osmolality caused by NaCl, KCl, sorbitol or maltose. The increase in medium osmolality (700–1,500 mosml/kg) was accompanied by the inhibition of growth (growth rate, biomass yield) and ethanol production (specific productivity and yield) In contrast, levan synthesis was less affected or even stimulated and, as a consequence, levan specific productivity was increased significantly. A decrease in the anabolic growth parameters correlated with a parallel inhibition of glucose‐6‐P dehydrogenase and alcohol dehydrogenase (isoenzyme ADH II) activities. A significant inverse linear relationship (r = − 0.932, 1 − P = 0.01) was observed between the values of the specific productivities of ethanol and levan. This relationship was confirmed independently by a controlled reduction of growth and ethanol productivity (3.75–4.75 mM sodiumbisulphite as an acceptor of acetaldehyde formed in the pyruvate decarboxylase reaction). As further support of this relationship, a significant inverse correlation was observed between levan specific productivity and ATP concentration in Zymomonas mobilis cells, most probably demonstrating that a reduced level of energetic metabolism is favourable for levan production.
Formation of aminium lactates in lactic acid fermentation preparation and characterization of 1,4‐piperazinium‐(L,L)‐dilactate obtained fromL(+)‐lactic acid (part I)
Authors: Kamm B. , Kamm M. , Richter K.
Published: December 2004

The potential for the production of 1,4‐piperazinium‐(L, L)‐dilactate fromL(+)‐lactic acid preparations obtained by fermentation was studied. Piperazinium dilactate was found to be a very suitable source material for poly(lactic acid) production. In a novel polymerization process, the intermediate dilactide was directly formed in the salt melt at a moderate temperature. High‐performance cultivation ofLactobacillus paracaseion a glucose‐MRS medium was carried out using high‐viability inocula. After the cell mass had been removed from the fermentation broth by centrifugation and/or ultrafiltration, the lactic acid solution was concentrated to 45% [w/w] by a two‐stage electrodialysis process. Two methods of preparing 1,4‐piperazinium dilactate were developed: the first from the medium‐concentrated lactic acid (45%) and the second from a highly‐concentrated lactic acid (85%) obtained by evaporation from the first one. Because there were no physical data on 1,4‐piperazinium‐(L, L)‐dilactate in specialized literature, the pure product was characterized according to its solubility characteristics, melting point and spectroscopic analysis.
Selection of yeast strain and fermentation conditions for high‐yield ethanol production from lactose and concentrated whey
Authors: Szczodrak J. , Szewczuk D. , Fiedurek J. , Rogalski J.
Published: December 2004

A total of 65 yeast strains were screened for their ability to grow and ferment lactose in a standard DURHAM tube test at 30 °C. Based on the kinetic parameters for lactose and whey lactose fermentations in shake flask cultures, the strain Candida psedotropicalis 65 was chosen for further studies.

Some of the cultural parameters affecting ethanolic fermentations on lactose were standardized. At an initial lactose concentration of 100–120 g/l in the medium containing concentrated whey or lactose, at 40 °C and within 48 h, the selected strain reached an ethanol concentration of 41–59 g/l, an ethanol productivity of 1.3–3.0 g/l/h, a lactose consumption of 99%, an ethanol yield 0.4–0.49 g/g and a biomass yield of 0.027 g/g.
Correlation between hypericin content and the ploidy of somaclones of Hypericum perforatum L.
Authors: Čellárová E. , Brutovská R. , Bruňáková K. , Daxnerová Z. , Weigel R. C.
Published: December 2004

An altered ploidy level was observed in plants regenerated by adventitious shoot formation from seedlings of Hypericum prformatum L. (2n = 4x = 32). Among the somaclones of the Ro generation, the presence of diploids (2n = 2x = 16), triraploids (2n = 3x = 24), tetraploids (2n = 4x = 32) and mixoploids was detected. Cytogenetic analyses of the R1 and R2 progenies showed that the chromosomal instability of the Ro somaclones was transferred onto the next generation.

While almost all the seed progeny of diploids (100% in R1 and 94% in R2) progenies showed that the chromosomal instability of the Ro somaclones was transferred onto the next generations.

While almost all the seed progeny of diploids (100% in R1 and 94% in R2) and more than 60% of tetraploids (61% in R1 and 73% in R2) retained their chromosome number, cytogenetic diversity was observed in the progeny of triploids, mixoploids and some tetraploids.

Somaclones and their offspring were analyzed for hypericin content. Statistical evaluation showed a correlation between hypericin content and ploidy during a two‐year cultivation of R0 somaclones and in their R1 and R2 progenies.
Effects of anoxic conditions on the enzymatic conversion of D,L‐2‐amino‐thiazoline‐4‐carboxylic acid to L‐cystine
Authors: Nam K. H. , Ryu O. H. , Park J. , Shin C. S.
Published: December 2004

The effects of anoxic conditions on product inhibition and the stability of L‐ATC hydrolase were investigated in the conversion of D,L‐2‐amino‐Δ2‐thiazoline‐4‐carboxylic acid (D,L‐ATC) to L‐cystine using the cell free extract enzyme of Pseudomonas sp. in the presence of hydroxylamine. At L‐cysteine equivalent levels, where one mole of L‐cystine was counted as two moles of L‐cysteine, L‐cystine inhibited the L‐ATC hydrolase reaction to a greater extent than L‐cysteine. In air, the product occurred predominantly as L‐cystine (94.9%), whereas in a nitrogen atmosphere the product occured as a mixture of L‐cysteine (39.3%) and L‐cystine (40.7%). As a result, less product inhibition took place in nitrogen. The activity of L‐ATC hydrolase was almost fully lost after 20 h of incubation by shaking at 30 °C in air, but considerable activity remained under the anoxic conditions of nitrogen. A kinetic analysis of the reactions confirmed that reduced product inhibition and enhanced enzyme stability in nitrogen result in a more efficient enzyme reaction. The inactivation rate constant (k1) was estimated to be 0.11 h−1 in nitrogen and 0.22−1 in air, indicating that the stability of L‐ATC hydrolase in nitrogen was greater than in air. The values of the Kp1 and Kp2 constants related to product inhibition were 43.36 mM and 30.48 mM for L‐cysteine and L‐cystine, respectively, where higher values were an indication of less product inhibition. The value of the rate constant (k2) for the oxidation of L‐cysteine to L‐cystine was 0.09 h−1 in nitrogen and 1.01 h−1 in air, suggesting that the oxidation of L‐cysteine to L‐cystine proceeds faster in air than in nitrogen.
Coconut cake – a potent substrate for the production of lipase by Candida rugosa in solid‐state fermentation
Authors: Benjamin S. , Pandey A.
Published: December 2004

Investigations were conducted with the aim of producing extracellular lipase from Candida rugosa by solid‐state fermentation (SSF), using coconut oil cake (COC) as a solid substrate. To optimize production, various modifications were made to enrich the substrate by supplementing it with mineral solution, different carbon sources and several inorganic as well as organic nitrogen sources. Among them, urea (1%), peptone (3%) and maltose (5%) were found to be most suitable. Addition of olive oil (10%) encouraged lipase synthesis. The maximum lipase activity in the enriched substrate was 87.76 units per gram of dry fermented substrate [U/gds] compared to 25.81 U/gds in the raw cake at 96 h of fermentation, and growth was as high as 14.44 mg/gds of glucosamine. This was reached at 72 h in the enriched substrate. C. rugosa growth was calculated indirectly by estimating the glucosamine content in the cell wall after its hydrolysis. The enzyme yield was far better than any values reported as yet.
Growth and formation of poly (hydroxybutyric acid) by Methylobacterium rhodesianum at methanol concentrations of above 25 g/I
Authors: Bormann E.‐J. , Leissner M. , Beer B.
Published: December 2004

Methylobacterium rhodesianum MB 126 was cultivated using extended cultures without outflow. The feeding regime was based on the pH‐regulated synchronous dosages of ammonia, methanol, phosphatc and trace elements according to supposed stoichiometric relations. The acidity of the culture medium was kept constant at pH 6.8, whereas the dissolved oxygen concentration was adjusted at 80% of saturation by autoregulation of the stirrer speed. However, besides testing technical conditions, two types of fermentations were discovered which are described in this paper. Firstly, although at the beginning of the bioprocesses the impeller speed increased up to 2,000 rpm, a decrease of dissolved oxygen down to zero was unavoidable. Secondly, methanol was accumulated temporarily up to 44 g/l and 26 g/l at 23 h of fermentation time and without inhibition of growth at least up to 30 g/l or PHB production. During this accumulation of the carbon substrate, exponential growth phases were detected showing growth rates of μ = 0.20/h and 0.21/h. But then, phases of retarded growth followed, whereas the methanol disappeared either continuously or after a steady level. In the course of a 54‐h fermentation period, the synthesized PHB amounted to a content of above 50% of cell dry mass. From this data, a volumetric productivity of 0.4 g PHB/lxh was estimated. Moreover, the growth related yield coefficients were calculated to YX/MeOH = 0.21 and YX/MeOH = 0.14, whereas the product related yield coefficients amounted to YPHB/MeOH = 0.12 and YPHB/MeOH = 0,09. Since the shift down of growth rates as well as the production of PHB agreed in time with partial oxygen limitation (40% oxygen saturation), the competition observed between the tricarboxylic acid cycle and PHB synthesis was discussed. Summarizing the results, it was concluded that the frequently described inhibitory effect of methanol of above 2 g/l seems to be rather an effect of experimentally chosen conditions than of a general physiological phenomenon. Therefore, it could be demonstrated that the toxicity of methanol could be overcome if it was not dosed at different times but simultaneously with other medium components.
Cell reuse in submerged lactic acid batch fermentation
Authors: Richter K. , Beyer F.
Published: December 2004

The reusability of biomass in lactic acid batch fermentation with free cells of Lactobacillus paracasei was studied in a 2–1 fermenter and in a 50‐1 fermenter. In lab‐scale fermentation experiments, 33 to 100% of the cell mass formed was reused in the subsequent batch in each case. In a series of seven consecutive batches, maximum values of lactate formation productivity of 6.32 to 11.54 g/l × h were observed at initial cell concentrations of 2.1 to 24.6 g/l. In all of the experiments, the initial cell viability was 78% or greater than 78%, and the final cell viability did not fall below 70%. At cell concentrations above 20 g/l, the productivity of lactic acid formation did not increase further, but remained constant. Because its level could be influenced by varying the proportions between the content of yeast extract, peptone and initial cell mass (1:1:2, 1:1:1 and 3.3.1) in the medium and no inhibitory effects were observed, this finding can be attributed to nutrient limitation. A low degree of cell reuse was reached in an analogous series of experiments carried out in a 50‐1 fermenter. In this case, the initial cell concentration varied between 0.5 and 1.1 g/l, and therefore cell growth was not limited by nutrients in the first period of fermentation. Lactate production was still stable after six cell‐reuse operations. The lactic acid yield did not fall below 90%. Temporary storage of the biomass in a refrigerator for a time interval of one to two weeks caused no significant impairment of overall lactate production, but a proportional prolongation of the lag phase occurred with increasing duration of storage.
Purification and immobilization of dextranase
Authors: Rogalski J. , Głowiak G. , Szczodrak J. , Pleszczyńska M. , Szczodrak Z. , Wiater A.
Published: December 2004

An enzymic characteristic of Novo dextranase was presented. In addition to a high dextranolytic activity (7,200 U/ml), the crude enzyme also contained small amounts of protease, glucoamylase, polygalacturonase, carboxymethylcellulase, laminarinase and chitinase. A highly purified dextranase was then simply separated from a commercial preparation by column chromatographies on DEAE‐Sepharose, CM‐Sepharose, and by chromatofocussing on Polybuffer Exchanger PBE‐94. The enzyme was recovered with an over 200‐fold increase in specific activity and a yield of 84%. The final preparation was homogeneous, as observed during high performance liquid chromatography (HPLC). Size‐exclusion HPLC indicated that dextranase had a molecular mass of 35 kDa and its isoelectric point, established by chromatofocussing, was 4.85. Analysis of the dextran break‐down products indicated that purified dextranase represents an endolytic mode of action, and isomaltose and isomaltotriose were identified as the main reducing sugars of dextran hydrolysis. The enzyme was then covalently coupled to the silanized porous glass beads modified by glutaraldehyde (Carrier I) or carbodiimide (Carrier II). It was shown that immobilization of dextranase gave optimum pH and temperature ranges from 5.4 to 5.7 and from 50°C to 60°C, respectively. The affinity of the enzyme to the substrate decreased by a factor of more than 13 for dextranase immobilized on Carrier I and increased slightly (about 1.4‐times) for the enzyme bound to Carrier II.
Biodegradability of lignosulphonate by Streptomyces viridosporus strain T7A and a mixed natural microbial population antagonistic effects
Authors: Hernandez‐pérez G. , Goma G. , Rols J. L.
Published: December 2004

The ability of a mixed natural microbial population, collected in an aerated lagoon treating Fluff pulp effluent and Streptomyces viridosporus strain T7A, to degrade lignosulphonate was evaluated. S. viridosporus growing in a mineral medium containing glycerol (7 g/l) and lignosulphonate (1 g/l) allowed 20% of lignosulphonate to be degraded after 18 days of incubation. A culture of the mixed population on culture medium after S. viridosporus growth was unable to degrade lignosulphonate products. Moreover, antagonism between S. viridosporus and the mixed population or between S. viridosporus and the isolated strains from this population was observed. The enhancement of lignosulphonate biodegradation by naturally occurring microorganisms in association with S. viridosporus (bioaugmentation strategy) seems to be difficult.
Culture conditions for the production of pectinolytic enzymes by the white‐rot fungus Trametes trogii on a laboratory scale
Authors: Levin L. , Forchiassin F.
Published: December 2004

Different cultural parameters that regulate pectinolytic enzyme production in vitro by Trametes trogii were studied. When grown in a medium containing pectin, T. trogii produced extracellular polymethylgalacturonase, polygalacturonase and pectin lyase but no pectate lyase activity. No significant differences in the maximum enzyme activities measured were observed with the addition of xylan, carboxymethylcellulose or both to the medium containing pectin. The addition of glucose to that medium considerably decreases all the activities studied, and in a medium with glucose as the sole carbon source no galacturonase activity could be measured, and pectin lyase activity was at its minimum. The low synthesis of pectin lyase in cultures containing glucose suggests that this enzyme is constitutive in contrast to the polygalacturonases that were not detected. The increase in pectin concentration stimulated growth and enzyme production. The highest specific activities were attained with the greatest concentration tested (15 g/l). Casamino acids were the best nitrogen source for enzyme production. Maximum growth was measured at pH 3.3; pH values of around 4.5 stimulated enzyme production, but high pectinase activities were also detected in media with more alkaline initial pH values (6.2 for galacturonases and 6.6 for lyases), probably owing to the specific induction of particular isoforms. In the range of 23 to 28°C, good results were obtained in growth as well as in enzyme production. The addition of Tween 80 promoted growth and gave the highest yield of polymethylgalacturonase and pectin lyase (0.37 and 36.2 E.U./ml, respectively). The highest polygalacturonase activity (1.1 E.U/ml) was achieved with polyethylene glycol. Tween 20 and Triton X‐100 inhibited growth and pectinase production.
Influence of different vitamin‐nitrogen sources on cell growth and propionic acid production from sucrose by Propionibacterium shermanii
Authors: Quesada‐Chanto A. , Da Costa J. P. C. L. , Silveira M. M. , Schroeder A. G. , Schroeder A. G. , Schmid‐Meyer A. C. , Jonas R.
Published: December 2004

Cell growth and organic acid production by Propionibacteria are dependent on the vitamin‐nitrogen source in the culture medium. Final cell and propionic acid concentrations produced by Propionibacterium shermanii, using corn‐steep liquor, were higher than those obtained utilizing yeast extracts. Since corn‐steep liquor is much cheaper than yeast extract, the process becomes more attractive. By calculating the specific growth rates, it was observed that the critical propionic acid concentration, that prevents all growth (μX = 0), is different depending on the vitamin‐nitrogen source used and its concentration. For example, for 5.0 and 15.0 g/l Oxoid yeast extract, those critical propionic acid concentrations were 16.0 and 27.0 g/l, respectively. Such propionic acid concentrations inhibit the cell growth, but not the formation of acid. The specific propionic acid production rate also indicates that the critical concentration for metabolic activity, when propionic acid is no longer produced (μP = 0), varies according to the vitamin‐nitrogen source and its concentration in the medium. For 5.0 and 15.0 g/l Oxoid yeast extract, those concentrations were 22.1 and 30.1 g/l, respectively.
Stability of a polyphenol oxidase from the white‐rot fungus Trametes versicolor in the presence of canola meal
Authors: Lacki K. , Duvnjak Z.
Published: December 2004

The stability of a polyphenol oxidase (PPO) preparation from the white‐rot fungus Trametes versicolor during a process for the enzymatic decrease of the phenolic content of commercial canola meal (CM) was investigated. The effects of temperature, pH, protein origin and concentration, and meal particles were considered. The results showed that the thermal stability of the enzyme preparation was significantly increased in the presence of CM. The half‐life times for the enzyme preparation, pre‐incubated with CM at 50, 60, 70 and 75°C, were 45, 10.5, 3.5 and 1.5 hours, respectively; this represents an increase in the thermal stability of the enzyme preparation of up to four times in the presence of CM compared to the stability in the absence of CM. This effect was caused by the protective actions of both the CM particles and CM proteins, with the former responsible for 90% of the observed effect. The thermal stability of the enzyme in the presence of CM, from which 20% of the extractable proteins was extracted, was 5% lower compared to the stability in the presence of untreated CM. Changes in pH level from 5.0 to 3.2 resulted in a loss of stability comparable to that observed when the pre‐incubation temperature was increased from 50 to 70°C.

A semi‐empirical model describing the changes in the concentration of the active enzyme pre‐incubated in the presence and absence of CM at various incubation temperatures was proposed. A very good agreement between the model and experimental data was obtained. The proposed model, together with a general set of model parameters, can be used as a tool for the optimization of a process for the upgrade of CM by enzymatically decreasing the meal's phenolic content.
Mineral content of the fruiting bodies of Pleurotus sajor‐caju (FR.) SINGER cultivated on different kinds of biomass
Authors: Patrabansh S. , Madan M.
Published: December 2004

Pleurotus sajor‐caju (FR.) SINGER was cultivated on different organic wastes, namely sericulture waste, Populus deltoides MARSH, and Eupatorium adenophorum SPRENG. Paddy straw was taken as the control and all the data were compared with it. The mineral contents of the fruiting bodies of Pleurotus sajor‐caju and the substrates on which the mushroom was grown were analyzed. Among the eight minerals determined (calcium, phosphorus, potassium, magnesium, sodium, iron, manganese and zinc), the potassium content was highest followed by phosphorus, magnesium and sodium. Analysis of the mineral contents of the substrates before cultivation had also been carried out. The mineral contents of the fruiting bodies of Pleurotus sajor‐caju were found to be different on different substrates. It was also observed that the mineral contents of the fruiting bodies of Pleurotus sajor‐caju increase when cultivated on substrates with higher mineral contents. The maximum mineral contents per 100 g of the substrates before cultivation were Ca – 347 mg; P – 151 mg; K – 1,805 mg; Na – 127 mg; Mg – 227 mg; Fe – 53 mg; Mn – 10 mg and zn – 3.1 mg. The mineral contents of the fruiting bodies of Pleurotus sajor‐caju per 100 g ranged as follows: Ca – 25.1 mg to 35.3 mg; P – 448 mg to 602 mg; K – 2,146 mg to 2350 mg; Na – 139 mg to 229 mg; Mg – 153 mg to 224 mg; Fe – 9.74 mg to 20.75 mg; Mn – 2.5 mg to 4.0 mg and Zn – 2.2 mg to 3.1 mg.
Use of various coffee industry residues for the cultivation ofPleurotus ostreatusin solid state fermentation
Authors: Fan L. , Pandey A. , Mohan R. , Soccol C. R.
Published: December 2004

Studies were carried out to evaluate the feasibility of using coffee industry residues,viz.coffee husk, coffee leaves and spent coffee ground as substrates in solid state fermentation (SSF) to cultivate edible mushroomsPleurotus. Eight strains ofPleurotus ostreatusand two strains ofPleurotus sajor‐cajuwere screened on a medium prepared from aqueous extract of coffee husk and agar. Based on best mycelial growth (9.68 mm/day) and biomass production (43.4 mg/plate in 9 days at 24°C), the strainP. ostreatusLPB 09 was selected for detailed studies. SSF was carried out using these substrates under different moisture conditions (45–75%) and spawn rates (2.5–25%). In general, although a 25% spawn rate appeared superior, the 10% spawn rate was recommended for all the three substrates in view of the process economics, as there was not any significant difference in the increase with 10 to 15%. The ideal moisture content for mycelial growth was 60–65% for coffee husk and spent coffee ground, and 60–70% for coffee leaves. The biological efficiency (BE), which is defined as the ratio of the weight of fresh fruiting bodies to the weight of dry substrate, multiplied by 100, and which indicates the fructification ability of the fungus for utilizing the substrate, was best with coffee husk. With coffee husk as the substrate, the first fructification occurred after 20 days of inoculation, and the biological efficiency reached about 97% after 60 days. When coffee leaves were used as the substrate, no fructification was observed even upon prolonged cultivation. With spent ground as the substrate, the first fructification occurred 23 days after inoculation and the biological efficiency reached about 90% in 50 days. There was a significant decrease in the caffeine and tannin contents (61 and 79%, respectively) of coffee husk after 60 days. It was remarkable to observe that caffeine was adsorbed onto the fruiting body (0.157%), indicating that it was not completely degraded by the fungal culture. However, no tannins were found in the fruiting body, indicating that the fungal strain was capable of degrading them. The results showed the feasibility of using coffee husk and spent coffee ground as substrates without any pre‐treatment for the cultivation of edible fungi in SSF, and provided one of the first steps towards an economical utilization of these otherwise unutilized or poorly utilized residues.
Wastewater treatment by the HCR‐process
Authors: Vogelpohl A.
Published: December 2004

The increasing requirements in wastewater treatment have led to the development of new wastewater treatment processes based on the know‐how and experience in reaction and process engineering of the chemical industry. Due to their compactness, closed operation and high flexibility, these new processes show a large potential for process integration and significant cost reduction in particular for highly polluted industrial wastewaters.

This paper discusses the HCR (high‐performance compact reactor) ‐ process, developed at the Mass Transfer Laboratory of the Technical University of Clausthal within the last decade. This process has been realized in more than 30 technical applications with a volume loading of up to 70 kg COD/m3 d and an energy consumption of about 0.4 kWh per kg CODelim.
Improving effectiveness in materials research
Authors: Wegner Gerhard
Published: December 2004

Panel Discussion: “Educate and cooperate” was the general message which came from the discussion of future trends in materials science during the meeting in Wilmington Delaware. Gerhard Wegner gives a European view of the proceedings, pointing out current trends and future aims in both the teaching of materials science and in the development and production of new materials.
Electrochromic Materials for optical switching devices
Authors: Bange Klaus , Gambke Thomas
Published: December 2004

The basic principles of electrochromism have been reported and discussed using the example of WO3, and some other important electrochromic materials have been described which have a number of interesting technical applications. Both compounds and materials used in ECDs were discussed and the principles of device design were portrayed, using as an example a reflective ASSD. By continuing the search for new electrochromic compounds and by further improving device design and cost optimization the applications of these materials are bound to increase.
Making A1 A15s
Authors: Cahn Robert W.
Published: December 2004

A15 Intermetallic superconductors do not receive as much media hype as the high‐Tc ceramic variety but they are big business, especially in the superconducting magnets area. This rapidly growing research field which includes melt‐spinning and rapid solidification technology is surveyed, and a report of the synthesis of Nb3Ge with critical currents of 5 × 1010 and 8 × 1010 A/M2 at fields of 0 and 15 T respectively is reviewed.
Inorganic materials II. Glass‐ceramics with controlled dielectric properties
Authors: Partridge Graham
Published: December 2004

The applications of glass‐ceramics in the electronics industry in just one of the topics covered in the second article of our series on inorganic materials. The advantages and disadvantages of this type of material compared with others are examined.
Diamond thin film technology I. Diamond deposition
Authors: Bachmann Peter K.
Published: December 2004

Diamond thin film technology I. In the first article of a regular series Peter Bachmann of the Philips Research Labs in Aachen, FRG, describes the different methods used to deposit diamond in films (see figure). Diamond in this form has many applications e.g. as an abrasive material, in lithography masks, microwave windows, in heat sinks, and in LEDs to name just a few.

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Crystal synthesis under langmuir monolayers
Authors: Mann Stephen , Heywood Brigid R. , Rajam Sundara , Walker Justin B. A. , Davey Roger J. , Birchall J. Derek
Published: December 2004

Organized organic surfaces can have a pronounced influence on the controlled crystallization of calcium carbonate. The effect is based on an inorganic‐organic molecular recognition process which is important, for example, in biomineralization. The contributions of headgroup charge and ionic concentration are examined. One of the two types of vaterite (the less common polymorph of calcium carbonate) crystals grown are shown in the figure.

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Phase diagrams of monolayers of the long chain fatty acids
Authors: Bibo Anna M. , Peterson Ian R.
Published: December 2004

The characteristics of langmuir‐blodgett (LB) films depend on the phase of the water‐surface monolayer from which they have been depoisted. A range of long‐chain fatty acids have been studied and it is reported, for example, that there are a multiplicity of phases in these materials, a finding which is not in accord with currently held views.
The potential of The Graphite Lattice
Authors: Hüttinger Klaus J.
Published: December 2004

Carbon‐based materials including carbon fibers and composites are the subject of this review. Structural aspects are examined, for example the microstructure of a spun carbon fiber shown in the figure, and the strength and other properties of the materials analyzed with respect to various applicatiosn e.g. as biomaterials and in reinforcement technology.

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Conducting polymers—thirteen years of Polyacetylene Doping
Authors: Roth Siegmar , Filzmoser Maria
Published: December 2004

The insulator‐to‐metal transition, doping, the mechanism of conductivity, solitons, and organic ferromagnets are among the topics covered in this overview of developments in conducting polymers. The materials are already in commercial use in, for example, batteries. Further possibilities are examined and the latest developments highlighted.
Chemical modification of polymeric materials by physiologically active substances
Authors: Valuev Lev I. , Platé Nikolai A.
Published: December 2004

Physiologically active molecules, when incorporated into polymers through homo‐ or copolymerization, result in biomedical materials with applications based on their physico‐chemical, mechanical and biochemical properties. The authors provide an overview of the Russian contributions to the field which include hemocompatible polymers, biospecific hemosorbants for the removal of toxins from the blood stream, and polymeric medications.
Surface anlysis IV. Moving single atoms and breaking chemical bonds
Authors: Rabe Jürgen P.
Published: December 2004

Workers at IBM have recently demonstrated the manipulation of single atoms, using an STM to write their company;s name in letters 5 nm high, assembled from exnon atoms. The method used is described and trends in this area examined.
Direct imaging of Pd561(phen)38±2On and Au55(PPh3)12Cl6 clusters using scanning tunneling microscopy
Authors: Wierenga Harald A. , Soethout Luc , Gerritsen Jan W. , van de Leemput Bart E. C. , van Kempen Herman , Schmid Günther
Published: December 2004

The first images of isolated full‐shell ligand‐stabilized clusters have been obtained using STM (see figure). The clusters are ideal model systems for studying the relationship between cluster size and electronic properties as well as having applications in catalysts and filters.

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The performance of Superalloys
Authors: Gibbons Tom B.
Published: December 2004

Hot‐end components in today's aero turbofan engines are made from materials known as superalloys, typically based on NiCr, NiCrFe or CoCr systems. In the fifty years or so that have elapsed since the first superalloys were introduced, the temperature capability of the materials has increased by approximately 500° and the power output of aero gas turbines has risen from ∼︁ 20 kN of thrust to the 250 kN achievable today. The materials and their development are described.
Ultrathin organic films: Molecular Architectures for advanced optical, electronic and bio‐related systems
Authors: Fuchs Harald , Ohst Holger , Prass Werner
Published: December 2004

Ultrathin ordered organic films with a thickness of a few nanometers to about a tenth of a micrometer show considerable technological potential as a novel class of materials. Of particular interest are their tailor‐made electrical and optical properties which are related to their anisotropic molecular structure which itself can be controlled on a molecular scale. A. critical review is given of the different aspects of the potential technological applications of ultrathin organic films. Some underlying chemical concepts and the basic problems to be solved in synthesis and preparation prior to application are discussed.
Atomic sites of a bare surface modified with the tunneling microscope
Authors: Fuchs Harald , Schimmel Thomas
Published: December 2004

Research News: The reproducible direct labeling of atomic sites on a semiconductor surface at room temperature and under ambient conditions has recently been reported for the first time. The STM method used, which results in an increase in the apparent height of the atomic positions but not in the formation of other defects such as dislocations, could have significant technological relevance, for example for the storage of digital information on the atomic scale.
Polyelectrolyte glasses with linear and nonlinear optical properties
Authors: Meyer Wolfgang H. , Pecherz Janusz , Mathy Alfred , Wegner Gerhard
Published: December 2004

Communication: Polyelectrolyte glasses, composed of cationic polymers and anionic dyes have several advantages over traditionally prepared intrinsicly dyed optical glasses for linear‐(LO) and nonlinear optical (NLO) applications. Very high dye concentrations canb e achieved, homogeneous distribution of the dye results in high‐quality glasses, a large variety of LO‐ and NLO‐active counterieons are available, and the glasses are easily processed. The preparation and testing of the new materials is described.
Molecular magnetic materials in Il Ciocco
Authors: Gatteschi Dante , Kahn Olivier , Miller Joel S. , Palacio Fernando
Published: December 2004

Conference Reports: Joel Miller of Du Pont describes activities at a recent NATO Advanced Research workshop on molecular magnetic materials held in Italy, and Siegmar Roth of the Max Planck Institute for Solid State Research in Stuttgart reports on a conference on synthetic metals held in southern Germany.
Carbohydrate‐modified conducting polymers synthesis and electrochemistry of sugar‐linked azulenes polyazulenes
Authors: Bross Peter Alexander. , Schöberl Ulrich , Daub Jörg
Published: December 2004

Communication: Chiral‐polymer electrodes and electochemical sensor devices are two pro potential applications for carbohydrate‐modified conducting polymers with a polyazulene backbone (see figure where R is a sugar). Carbohydrate modification, whitel providing the conducting polymer with molecular‐targeting capability also lends water‐solubility to the intrinsicly hydrophobic azulene group and should therefore enable chemistry and electropolymerization in aqueous solution.

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Paramagnetic nematic liquid crystals
Authors: Marcos Mercedes , Serrano José‐Luis
Published: December 2004

Research News: Orientation of nematic liquid crystals (LCs) in a magnetic field can be achieved if a paramagnetic unit is incorporated into the system. Recently vanadyl and copper based paramagnetic LCs have been developed which show promise in the magnetic characterization of LCs. The paramagnetic complexes can be added to the sample of interest and the whole studied using NMR or ESR.