New approach for selecting pectinase producing mutants of Aspergillus niger well adapted to solid state fermentation.

The aim of this paper is to review and study a new approach for improving strains of Aspergillus niger specially adapted to produce pectinases by Solid State Fermentation (SSF) with materials having low levels of water activity (a(w)), i.e., coffee pulp. Special emphasis is placed on the use of two antimetabolic compounds: 2-deoxy-glucose (DG) and 2,4-dinitro-phenol (DNP) combined with a water depressant (ethylene glycol = EG) in order to put strong selection pressures on UV treated spores from parental strain C28B25 isolated from a coffee plantation. Such a strain was found to be DG sensitive. Results suggested the existence of a reciprocal relation between adaptation of isolated strains to SSF or to Submerged Fermentation (SmF) systems. Preliminary physiological analysis of isolated strains showed that at least some few initially DG resistant mutants could revert to DG sensitive phenotype but conserving increased pectinase production. Also it was found that phenotype for DNP resistance could be associated to changes of DG resistance. Finally, it was found that low levels of a(w) produced by adding 15% EG to agar plates, were a significant selection factor for strains well adapted to SSF system.

Packed bed column fermenter and kinetic modeling for upgrading the nutritional quality of coffee husk in solid-state fermentation.

Studies were carried out to evaluate solid-state fermentation (SSF) for the upgradation of the nutritional quality of coffee husk by degrading the caffeine and tannins present in it. SSF was carried out by Aspergillus niger LPBx in a glass column fermenter using factorial design experiments and surface response methodology to optimize bioprocess parameters such as the substrate pH and moisture content and aeration rate. The first factorial design showed that the moisture content of the substrate and aeration rate were significant factors for the degradation of toxic compounds, which was confirmed by the second factorial design too. The kinetic study showed that the degradation of toxic compounds was related to the development of the mold and its respiration and also to the consumption of the reducing sugars present in coffee husk. From the values obtained experimentally for the oxygen uptake rate and CO(2) evolved, the system determined a biomass yield (Y(x/o)) of 3.811 (g of biomass).(g of consumed O(2))(-1) and a maintenance coefficient (m) of 0.0031 (g of consumed O(2)).(g biomass of biomass)(-1).h(-1). The best results on the degradation of caffeine (90%) and tannins (57%) were achieved when SSF was carried out with a 30 mL.min(-1) aeration rate using coffee husk having a 55% initial moisture content. The inoculation rate did not affect the metabolization of the toxic compounds by the fungal culture. After SSF, the protein content of the husk was increased to 10.6%, which was more than double that of the unfermented husk (5.2%).

Potential of solid state fermentation for production of ergot alkaloids.

Production of total ergot alkaloids by Claviceps fusiformis in solid state fermentation was 3.9 times higher compared to that in submerged fermentation. Production was equal in the case of Claviceps purpurea but the spectra of alkaloids were advantageous with the use of solid state fermentation. The data establish potential of solid state fermentation which was not explored earlier for production of ergot alkaloids.

Importance of medium pH in solid state fermentation for growth of Schwanniomyces castellii.

Utilization of soluble starch by Schwanniomyces castellii in a solid state fermentation system was highest in unbuffered medium when initial and final pH of the medium were 6.5-7.0 and 4.0-4.6, respectively. An economic strategy involving the use of urea as a sole nitrogen source in medium with initial pH of 6.5 allowed maximum substrate utilization in the absence of buffer and without any contamination in column fermenter.

Biotechnological potential of coffee pulp and coffee husk for bioprocesses.

Advances in industrial biotechnology offer potential opportunities for economic utilization of agro-industrial residues such as coffee pulp and coffee husk. Coffee pulp or husk is a fibrous mucilagenous material (sub-product) obtained during the processing of coffee cherries by wet or dry process, respectively. Coffee pulp/husk contains some amount of caffeine and tannins, which makes it toxic in nature, resulting the disposal problem. However, it is rich in organic nature, which makes it an ideal substrate for microbial processes for the production of value-added products. Several solutions and alternative uses of the coffee pulp and husk have been attempted. These include as fertilizers, livestock feed, compost, etc. However, these applications utilize only a fraction of available quantity and are not technically very efficient. Attempts have been made to detoxify it for improved application as feed, and to produce several products such as enzymes, organic acids, flavour and aroma compounds, and mushrooms, etc. from coffee pulp/husk. Solid state fermentation has been mostly employed for bioconversion processes. Factorial design experiments offer useful information for the process optimization. This paper reviews the developments on processes and products developed for the value-addition of coffee pulp/husk through the biotechnological means.

Comparison of volatile compound production in fruit body and in mycelium of Pleurotus ostreatus identified by submerged and solid-state cultures.

Comparative analyses of the production of volatile compounds by Pleurotus ostreatus JMO.95 fruit body and its corresponding mycelium grown in liquid, on agar surface, and on solid support cultures were carried out by dynamic headspace concentration using gas chromatography/mass spectrometry and gas chromatography sniffing. The aroma produced by fruit body was owing essentially to the presence of octan-3-one and, to a lesser extent, to octan-3-ol. Other compounds, such as oct-1-en-3-ol, oct-1-en, 2-methylbutanol, and alpha-pinene were also present in low concentrations. Comparison of aromatic spectra of the fruit body with that of mycelia obtained under different culture conditions indicated that the main aromatic compounds present in the P. ostreatus fruit body and mycelium were produced in the same proportions on agar surface and on solid support culture, but not under submerged conditions.

Effect of caffeine concentration on biomass production, caffeine degradation, and morphology of Aspergillus tamarii.

The aim of the present study was to evaluate the effect of the initial caffeine concentration (1-8 g/L) on growth and caffeine consumption by Aspergillus tamarii as well as pellet morphology, in submerged fermentation. Caffeine was used as sole nitrogen source. At 1 g/L of initial caffeine concentration, caffeine degradation was not affected, resulting in a production of 8.7 g/L of biomass. The highest biomass production (12.4-14.8 g/L) was observed within a range of 2 to 4 g/L of initial caffeine concentration. At these initial caffeine concentrations, after 96 h of fermentation, 41-51 % of the initial caffeine was degraded. Using an initial caffeine concentration of 2-3 g/L, the highest specific growth rate was observed (µ = 0.069 1/h). Biomass production decreased at 8 g/L of initial caffeine concentration. A. tamarii formed mainly pellets at all concentrations tested. The size of the pellet decreased at a caffeine concentration of 8 g/L.

[Hydrolysis of cellulose by fungi. 1. Screening of cellulolytic strains]. / Hydrolyse de la cellulose par les moisissures. 1. "Screening" des souches cellulolytiques.

Trichoderma harzianum was selected from 30 strains of cellulolytic fungi with the aim of producing cellulases by solid state fermentation of lignocellulosic substrates. Special attention was paid to cellulase production (i.e. carboxymethylcellulase and filter paper activity), apical growth and conidia production. Under the conditions of our experiments, T. harzianum exhibited the highest cellulasic activities with 1,315 IU/l of carboxymethyl cellulose and 80 IU/l of filter paper activity. Apical growth (1 mm/h) and yield of conidial production (3.25 x 10(10) conidia/g of substrate dry weight) were also valuable characteristics of this strain in the use of solid state fermentation.

[Hydrolysis of cellulose by fungi. II. Production of cellulases by Trichoderma harzianum by fermentation in liquid media]. / Hydrolyse de la cellulose par les moisissures. II. Production de cellulases de Trichoderma harzianum par fermentation en milieu liquide.

Microcristalline cellulose (cellulose Avicel, Merck) supported growth of Trichoderma harzianum and induced production of cellulases in liquid cultures. After 50 h growth, the total cellulasic activities present in both the supernatant and the mycelium were 3,000 IU/l of carboxymethyl cellulose, 400 IU/l of filter paper activity, and 4 IU/l of cotton activity corresponding to 1.7 g/l of proteins. Cellulase production could be increased by a preliminary treatment of cellulose, and pH regulation during growth. The influence of inoculum concentration was studied and an optimum of 3 x 10(7) conidia/g dry weight of substrate was demonstrated. Using a synthetic culture medium, a soluble factor of germination was demonstrated which could be leached out by 3 successive washings of conidia.

A review of collaborative partnerships as a strategy for improving community health.

Collaborative partnerships (people and organizations from multiple sectors working together in common purpose) are a prominent strategy for community health improvement. This review examines evidence about the effects of collaborative partnerships on (a) community and systems change (environmental changes), (b) community-wide behavior change, and (c) more distant population-level health outcomes. We also consider the conditions and factors that may determine whether collaborative partnerships are effective. The review concludes with specific recommendations designed to enhance research and practice and to set conditions for promoting community health.

Effect of the nitrogen source on caffeine degradation by Aspergillus tamarii.

AIMS: To evaluate caffeine degradation and nitrogen requirements during Aspergillus tamarii growth in submerged culture. METHODS AND RESULTS: Aspergillus tamarii spores produced on a coffee infusion agar medium added with sucrose were used. Several caffeine and ammonium sulphate concentrations (0-1 and 0-1.36 g l-1, respectively) were tested simultaneously on fungal biomass production and caffeine degradation. An additional caffeine pulse (4 g l-1) was added for all experiments after 48 h of fermentation. Results revealed that when using 0.90 g l-1 of caffeine and 0.14 g l-1 of ammonium sulphate, biomass production and caffeine degradation were enhanced. Highest biomass production (Xmax = 9.87 g l-1) with a specific growth rate (micro) of 0.073 h-1 and caffeine degradation rate of 0.033 g l-1 h-1, was observed under these conditions. CONCLUSIONS: Caffeine degradation as well as biomass production were characterized. SIGNIFICANCE AND IMPACT OF THE STUDY: These studies set the stage for future characterization studies of intracellular enzymes involved in caffeine degradation. Moreover, results observed may help in the biotreatment of residues from the coffee agroindustry.

Screening of microorganisms for biodegradation of poly(lactic-acid) and lactic acid-containing polymers.

The ability of some microorganisms to use lactic acid stereocopolymers and copolymers with glycolic acid as sole carbon and energy sources was studied under controlled or natural conditions. First, 14 filamentous fungal strains were tested in liquid cultures, adopting total lactic acid consumption, nitrogen source exhaustion, and maximal biomass production as selection criteria. Two strains of Fusarium moniliforme and one strain of Penicillium roqueforti were able to totally assimilate DL-lactic acid, partially soluble racemic oligomers (MW = 1,000), and the nitrogen source. Only one strain of F. moniliforme was able to grow on a poly(lactic acid)-glycolic acid copolymer (MW = 150,000) after 2 months of incubation at 28 degrees C on synthetic agar medium. Mycelium development was examined by scanning electron microscopy. F. moniliforme filaments were observed to grow not only at the copolymer surface but also through the bulk of the copolymer. In a second approach, plates made of a racemic poly(lactic acid) were buried in the soil before being incubated in petri dishes containing mineral agar medium under controlled conditions. Five strains of different filamentous fungi were isolated, and their ability to assimilate racemic poly(lactic acid) oligomers was tested in liquid cultures.

[Distribution of heterotrophic aerobic microflora and specially denitrifying and free-living nitrogen-fixing bacteria in the rhizosphere of rice (author's transl)]. / Distribution de la microflore hétérotrophe aérobie et en particulier des bactéries dénitrifiantes et fixatrices d'azote libres dans la rhizosphère du riz.

The distribution of heterotrophic aerobic bacteria, actinomycetes and fungi was estimated in three samples (rhizospherical soil (SR), rhizoplane (R) and endorhizosphere (ER)) obtained from one rice seedling which had grown in pot during four mounths in a Casamance grey soil. The number of microbial populations were about the same from one sample to another: 1.1 to 2 X 10(8) bacteria, 3.3 to 8.6 X 10(6) actinomycetes and 0.2 to 8.9 X 10(4) fungi per gram of dry soil (SR) or dry roots (R and ER). The denitrifying and free-living nitrogen fixing bacteria were numerous (10(7) bacteria/g) but lower for ER where the number of actinomycetes remained high. Thirty-six bacterial strains have been isolated from every sample with the use of a grid of isolation. The Gram-negative bacteria were dominant in SR and R where they represented respectively 70 and 94% of total count. The major groups were non-sporulated Gram-variable rods (SR) and Alcaligenes-like bacteria (ER). The pseudomonads represented quite 15% of total count in the three samples. On the other hand, the frequency of endospore-forming Gram-positive bacteria was high only in R where the Bacillus group was estimated to 45% of total count. Only 5 free-living nitrogen-fixing bacterial strains had shown a denitrifying ability.

Cellulase production by trichoderma harzianum in static and mixed solid-state fermentation reactors under nonaseptic conditions.

Cellulase production from lignocellulosic materials was studied in solid-state cultivation by both static and mixed techniques under nonaseptic conditions. The effects of fermentation conditions, such as moisture content, pH, temperature, and aeration, on cellulase production by Trichoderma harzianum using a mixture of wheat straw (80%) and bran (20%) were investigated. With a moisture content of 74% and a pH of 5.8., 18 IU filter paper activity and 198 IU endoglucanase activity/g initial substrate content were obtained in 66 h. The extension from static column cultivation to stirred tank reactor of 65 L capacity gave similar yields of cellulase.

Engineering clinician leadership and success in tobacco control: recommendations for policy and practice in Hungary and Central Europe.

Decades of research and advocacy to control tobacco use and related public-health harm have not counterbalanced the tobacco industry's successful stronghold, which is ever-increasing in countries with weaker anti-tobacco leadership. Current rates of tobacco use and harm in Hungary and other Central European countries mark them as some of the industry's greater successes. Following the Behavioural Ecological Model, a framework for behavioural and cultural change, this paper reviews important ways that dentists, physicians and other healthcare providers can counter the tobacco industry's influence on patients, communities, and the nation. The analysis includes policies and practices shown to be effective in controlling and undermining the tobacco industry, and outlines new policies and practices that show promise based on the behavioural change framework. The components of an all-encompassing tobacco-control programme are described through explicit recommendations for research, practice and policy that are necessary to establish a professional and societal culture that extinguishes the influence and harm of the tobacco industry in Hungary, Central Europe and developing countries worldwide.

[Numerical taxonomy of a thermophilic "Bacillus" species isolated from West African rice soils (author's transl)]. / Taxonomie numérique de Bacillus thermophiles isolés de sols de rizère de l'Afrique de l'Ouest.

Fifty-seven strains of endospore-forming thermophilic bacteria, 37 of which were capable of denitrification, were isolated from rice soils of West Africa. They were compared with 17 strains of similar bacteria from culture collections, utilizing a total of 123 morphological, physiological and biochemical characteristics. A numerical analysis was performed using the complete linkage-clustering method and the Khi2 test. Seventy-five percent (55 strains) could be included in 12 groups at a taxonomic distance of 0.015. Wild strains of denitrifiers issued in phenons 8 to 12 and strains of phenon 4 (not denitrifying) were related to the named strains of phenons 1 and 7 (Bacillus stearothermophilus). Twenty-two wild strains, and 5 strains from culture collections, were only thermotolerating without growth at 65 degrees C. The strains of phenon 3 were related to the 3 named strains of B. coagulans. Phenons 5 and 6 were composed of strains related to B. circulans. The strains of phenon 2 denitrified and showed a swollen central endospore; they were closely related to B. brevis. The denitrifying thermophilic strains isolated from rice soils (phenons 8 to 12) were related to the first group (B. kaustophilus) of Walker and Wolf but their base compositions of DNA were significantly different from those found for the reference strains.

[Taxonomic study of free nitrogen-fixing bacteria isolated from the endorhizosphere of rice]. / Etude taxonomique de bactéries azotofixatrices libres isolées de l'endorhizosphère du riz.

Twenty strains of free-living N2-fixing bacteria, isolated from the endorhizosphere of rice in rice soils of Senegal, were studied on the basis of 259 morphological, physiological, biochemical and nutritional characters. Half of them were Gram-negative small rods with polar flagella and showing a strictly respiratory metabolism; they were characteristic of the genus Pseudomonas. A first group of 6 strains was related to the P. cepacia-P. marginata group characterized by lophotrichous flagella; they accumulated polyhydroxybutyrate, assimilated arginine and betaine, grew at 41 degrees C and showed a wide nutritional spectrum with DNA GC% of 67-68. The second group of 4 strains was related to the P. lemoignei group because of (a) its monotrichous flagella, (b) poly-beta-hydroxybutyrate accumulation, (c) failure to assimilate arginine and betaine and to grow at 41 degrees C, (d) lack of arginine dihydrolase and (e) its narrow nutritional spectrum. DNA GC% was 65. These 4 strains were also denitrifying bacteria. Six strains were related to the genus Alcaligenes because of their strictly respiratory metabolism and their peritrichous flagella; their nutritional spectrum was variable and one of them was a denitrifier. DNA GC% was 68. One strain was related to Aeromonas hydrophila of the Vibrionaceae family; it consisted of Gram-negative and oxidase-positive small rods with monotrichous polar flagella and respiratory and fermentative metabolism without gas evolution. This strain essentially assimilated sugars and its DNA GC% was 63. Another strain was a Gram- and oxidase-negative small rod with peritrichous flagella and respiratory and fermentative metabolism with gas evolution. Sugars, organic acids and amino acids were assimilated. The DNA GC% was 53. This strain was related to Enterobacter cloacae of the Enterobacteriaceae family, but it showed the additional faculty of denitrification. The last two strains studied were spirilla with amphitrichous flagella characteristic of the genus Aquaspirillum. They showed a strictly respiratory metabolism and a DNA CG% of 60-64. This study allowed us to show the N2-fixing capacity of species of Pseudomonas, Alcaligenes and Aeromonas which had been devoid of N2-fixing bacteria until this time. All strains studied were microaerophilic for N2 fixation.

Biological detoxification of coffee husk by filamentous fungi using a solid state fermentation system.

Studies were carried out on detoxification of coffee husk in solid state fermentation using three different strains of Rhizopus, Phanerochaete, and Aspergillus sp. Fungal strains were selected by their ability to grow on a coffee husk extract-agar medium. Using R. arrizus LPB-79, the best results on the degradation of caffeine (87%) and tannins (65%) were obtained with pH 6.0 and moisture 60% in 6 days. When P. chrysosporium BK was used, maximum degradation of caffeine and tannins were 70.8 and 45%, respectively, with coffee husk having 65% moisture and pH 5.5 in 14 days. The Aspergillus strain, isolated from the coffee husk, showed best biomass formation on coffee husk extract-agar medium. Optimization assays were conducted using factorial design, and surface response experiments with Aspergillus sp. The best detoxification rates achieved were 92% for caffeine and 65% for tannins. The results showed good prospects of using these fungal strains, in particular Aspergillus sp., for the detoxification of coffee husk.

Production of pectinases by Aspergillus niger in solid state fermentation at high initial glucose concentrations.

Exopectinase (exo-p) and endopectinase (endo-p) production by Aspergillus niger CH4 in solid state culture was studied at initial glucose concentrations of 100, 250, 350 and 450 g/l. The highest activity of exo-p (35 U/g) was produced at 72 and 120 h in the medium containing 100 and 250 g glucose/l, respectively. The maximum endo-p activity (9 U/g) was produced at 72 h in the medium with 250 g glucose/l. The reduction in pectinase production at 350 and 450 g/l initial glucose concentration was due neither to repression of the synthesis of the enzyme nor to the glucose consumption rate of the strain but due to a drastic drop in pH of the medium.