Search

Hydroxycinnamic acids (HAs) have a potential application in the food and pharmaceutical industry because they are rich in phenolics. Feruloyl esterases release phenolic compounds from plant cell walls. Coffee pulp is rich in HAs linked to polysaccharides. A solvent extraction of free HAs was performed with aqueous methanol (80 %). A response surface methodology was applied to optimise the extraction of these compounds from coffee pulp, and the best results were obtained at 56 °C for 34 min. Alkaline and acid hydrolyses were performed to evaluate the content of linked HAs. Treated (extracted) coffee pulp was used to produce feruloyl esterases in solid-state fermentation by Aspergillus tamarii V12307, previously selected by a hydrolysis plate assay. Different dilutions of a culture medium were added to the coffee pulp, and the diluted medium with half the nutrients allowed for higher CO2 production. A specific growth rate (μCO2 ) of 0.25 h^–1 and a lag phase (tlag) of 14.3 h were observed under the selected conditions. Finally, enzymatic activities were 14.0 and 10.8 nkat per g of dried matter when methyl and ethyl ferulate were used as substrates, respectively. Productivities (9.3 and 7.2 nkat per g of dried matter per day, respectively) were higher when compared to other studies carried out in solid-state fermentation. Utilisation of coffee pulp for enzyme production improves the added value of this abundant by-product of the coffee industry.

Summary During the methanogenic fermentation of cassava peel in a plug flow digester, cyanide bound as linamarin in cassava was released as HCN in the fermentation liquor, and then eliminated by the activity of free enzymes and by non-enzymatic reactions. The raw cassava peel contained (1) the enzyme permitting the hydrolysis of linamarin and the liberation of HCN (linamarase), and (2) a cyanide detoxification enzyme (p-cyanoalanine synthase). Cyanide removal was sufficiently fast to maintain a cyanide concentration in the fermentation liquor which was non-inhibitory for the methanogenic microflora.

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.

At first some general considerations about specificity and characteristics of SSF, their advantages and disadvantages as compared to LSF, are presented. Microorganisms involved in solid substrate fermentations are identified, considering the better performances of filamentous fungi. The solid substrates and their basic macromolecular compounds are detailed in relation to this complex and heterogeneous system. Biomass measurement is examined in detail, as well as environmental factors, both essential for studying and optimising solid substrate fermentations.

Las xilanasas son endoglucanasas capaces de degradar xilano. Estas enzimas se pueden aplicar en varios procesos industriales como en la degradación de residuos agrícolas para obtener azúcares, los cuales se fermentan para producir etanol. La aplicación industrial, sin en embargo, requiere estabilidad principalmente a elevadas temperaturas, por ello existe gran interés en el estudio de microorganismos termófilos. En la presente investigación, se estudió la producción de xilanasas en un sistema de inmovilización con alginato de calcio de la bacteria FT3 anaeróbica termófila, aislada de la Región altiplánica de Bolivia. Los resultados muestran que en un cultivo en batch suplementado con cloruro de amonio como fuente de nitrógeno y xilano como fuente de carbono, la actividad xilanolítica fue de 0,2 UI/mL, y un rendimiento de producción de 0,004 mUI de xilanasa/g de xilano. Esta actividad fue incrementada a 1,2 UI/mL (0,009 mUI/g), en cultivo en batch con células encapsuladas en alginato cálcico de alta viscosidad al 2%. En la optimización de fuentes de carbono y nitrógeno, la actividad incrementó únicamente en el sistema de células encapsuladas, mientras que en el de células libres esto parece no influir. Es así, que las condiciones óptimas de cultivo en base a las fuentes carbono y nitrógeno fueron residuos de soya y extracto de levadura, a una concentración de 5 g/L y 0,2 g/L respectivamente, obteniéndose una actividad de 1,8 UI/mL (0,1 mUI/g). El sistema inmovilizado fue ensayado en cultivo continuo que permitió la producción de la enzima lbre de células. Se logró incrementar la actividad hasta 1,3 UI/mL (0,13 mUI/g). El cambio de NH4Cl por extracto de levadura como fuente de nitrógeno en cultivo continuo incrementó la actividad enzimática en el bioreactor hasta 3,3 UI/mL (0,15 mUI/g). Así mismo, el cambio de la fuente de carbono de xilano por hidrolizado de residuos de soya no incrementó la actividad enzimática, sin embargo ésta se mantuvo estable. (résumé d'auteur)

Studies on ensiling of spent solids from solid state fermentation process for production of cellulases by #Trichoderma harzianum$ showed that good quality ensiled solids can be obtained by using about 43% initial substrate dry matter with 0.3% ensiling additive. (Résumé d'auteur)

Las bacterias termófilas anaerobias son capaces de producir etanol como principal producto de fermentación a partir de un amplio espectro de substratos, como hexosas, di- y polisacáridos y varias pentosas. Existen muchas ventajas de llevar a cabo fermentaciones a elevadas temperaturas sin necesidad de aereación y enfriamieno; entre ellas la remoción constante de etanol y el bajo riesgo de contaminación. Sin embargo, son muy pocas las bacterias termófilas anaerobias eficientes, aún así este proceso es una esperanza ante la crisis mundial de energía. (Résumé d'auteur)

A fraction of procyanidin (PC) was purified from the cider apple and used as the sole carbon source in order to evaluate the potency of different filamentous fungi to grow and degrade them. Fiftegn filamentous fungi were screened in a mineral medium with or without glucose. Almost all the strains were observed to have PC degradation ability. Aspergillus fumigatus was the most efficient fungus that degraded >5OVo of PC after 72h of growth. This strain was selected for further studies. The PC cultured samples were analyzed by thiolysis-HPlC method and constitutive units (catechin units) ofPC polymer were quantified and characterized. Kinetics ofPC degradation revealed that the terminal units of PC decreased during fermentation and on the contrary, an increase in the average degree of polymerization (DPn) from 8 to 36 was also observed at the end of fermentation. These findings suggested that terminal units were possibly modifred by the enzymatic action of the fungus. Normal-Phase HPLC analysis showed that PC oligomers were degraded during the early phase

Three thermophilic fungal strainsRhizopus homothallicus 13a,Rhizomucor pusillus S5 andRhizomucor pusillus S8 were grown in solid state fermentation on sugar cane bagasse-olive cake mixture (50% each) at 47°C for 48 h. Humidity and pH increased during fermentation, from 5.1–5.2 to 5.5–6.1 and from 64% to 69% respectively. For all strains, O2 uptake rates reached a maximum of 1.7–2.2 ml/h/g IDM (initial dry matter) at an early stage of cultivation (7.5–9 h) and high respiratory activities (μr) were obtained (1.2–1.4 h-1). The maximal O2 uptake at 48h of culture was 28.1, 31 and 33.2 ml/g IDM for strains 13a, S5 and S8 respectively. All strains produced lipolytic activities, which varied from 15 U/g IDM for strain S8 to 47 U/g IDM for strain 13a when olive oil was used as enzyme substrate. The lipolytic activity of crude enzyme extracts from strain S 8 was specific of mid-chain length fatty acid esters. There was evidence of lipase activity (active on long chain fatty acid esters) and esterase activity (active on short chain fatty acid esters) for strain 13a. The latter one was present at 24h but not at 48h of culture. The specificity pattern of strain S5 extract looked similar to that of strain 13a. After incubation in n-heptane for 8 days at 37°C., the enzyme extracts retained 65%, 66% and 84% of initial activity for strains 13a, S5 and S8 respectively.

Forty-four fungal strains capable of growing at temperatures above 50 C were isolated from different samples of soil and coconut residues collected in Mexican tropical and subtropical regions. These thermophilic and thermotolerant fungal strains were identified by microscopical analysis using standard procedures. Three species were identified: Rhizomucor pusillus (Lindt)Schipper (19 strains), Rhizopus microsporus van Tieghem (6 strains), and Aspergillus fumigatus Fresenius (19 strains). Four strains identified as Rhizopus microsporus were ascribed to the variety rhizopodiformis; however, the other two strains showed new characteristics which require further analysis, such as a homothallic sexual reproduction. Aspergillus fumigatus was found in coconut residues as a common contaminant during the isolation of other thermophilic species. Strains were isolated from samples containing a high content of lipids (mainly from coconut coprah), and accordingly extracellular lipase biosynthesis was directly confirmed in Petri dishes for every strain.

Coffee is one of the most profitable crops in Latin America. Brazil is the biggest producer, consumer and exporter in the world. After coffee processing only 5.8% of the total matter is used for coffee production generating a large amount of waste, were no commercial value, that can hardly pollute the environment. The coffee husk conservation can be made by silage. Specific microorganisms can produce a standard ensilage when added in the process. The main goal of this work is to study the natural microflora present in the coffee husk and coffee pulp able to ensilage these by-products. The lactic acid bacteria responsible for this process were isolated and characterised and added in an ensilage process to accelerate the acid lactic production. First, in this work, fresh fruity coffee pulp were put fermented naturally and it was observed that the pH was maintained around 4 during two months. Then many bacteria were isolated from these natural fermented materials. Morphology, fermentative and biochemistry studies were used to identify and characterise the bacteria. These bacteria were able to grown in a coffee extract and change the pH 6 to around 4.4. Then, the second study was added these isolated bacteria in processed coffee husk to ensilage. It shows that is necessary to add the lactic acid bacteria to initiate the ensilage process. In the coffee husk fermentation, 107 CFU were added per g of matter and the pH was maintained around 4.8; microorganisms were viable for 2 months.

Three kinds of olive cakes from Moroccan area were used as substrates for solid state fermentation: 1) Crude Maasra Cake (CMaC) from a traditional unit of olive oil extraction (maasra), 2) Crude Exhausted Cake (CEC) from a semi-traditional unit, 3) Crude Mill Cake (CMC) collected from an industrial unit of olive oil extraction. Biochemical characterization of these olive cakes showed that these raw materials were rich in fibers (cellulose, hemi-cellulose and lignin), 46.8–55.8%. Fat content in CEC was lower (6.9%) than in CMaC (18.4%) and CMC (17.0%). Sixteen fungal strains were isolated from samples collected from olive cakes mainly from CMaC (11 strains). Solid state fermentation was used as a tool to screen these strains in terms of protein enrichment and fiber degradation. The best performances were obtained by the strainAspergillus niger S13. After 48h of fermentation, the maximal real proteins increase (RPI), actual loss in cellulose, actual loss in hemi-cellulose and actual loss in lignin were 9.3%, 19.4%, 22.1% and 4.3%, respectively.

The main objective of the present work was to produce a biological nematicide by SSF, with an important number of virulent spores of Paecilomyces lilacinus and Verticillium chlamydosporium by utilising coffee husk as substrate. Studies of the fermentation physical conditions, such as pH, temperature and initial moisture content were done by using an experimental design 23–1 followed by a complete design 32 to obtain the best fermentation conditions. The activity of the biocompost obtained with the fungi Paecilomyces lilacinus (strains Pl–1, Pl–2 and Pl–3) and Verticillium chlamydosporium (strain Vc-1), were evaluated against the nematode Meloydogyne incognita race 1. The measured responses were number of females and root weight. The nematophagous fungi Paecilomyces lilacinus Pl–1. showed a reduction in the order of 80%, with the exception of the strain of Paecilomyces lilacinus Pl–3, the results obtained with the other strains of fungi propitiated a reduction in the number of nematode females in order of 15 – 25 %.

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.

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%).

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.

cited By 36; International audience; The ability of Aspergillus tamarii V12A25 to use caffeine as sole nitrogen source was investigated in solid state fermentation (SSF) using two different supports, polyurethane foam (PUF) and sugarcane bagasse. Caffeine can be used in SSF as the sole nitrogen source, the carbon source being saccharose. If a simpler nitrogen source (ammonium sulphate, urea) is added to the medium containing caffeine, this source will be used first allowing fungal growth. If saccharose is still present when the simple nitrogen source has been degraded, caffeine will be used as the nitrogen source, together with saccharose. Caffeine at a concentration of 8 g/l has no effect on fungal growth when a simple nitrogen source is not limiting. The main difference between the two solid supports was the time required to complete the fermentation. With sugarcane bagasse as the support, substrates (caffeine, ammonium sulphate, urea) were degraded almost twice as fast as with PUF as the support. Theophylline and 3-methylxanthine, the major products from caffeine degradation, disappeared completely from the culture medium shortly after caffeine degradation stopped. The major advantage of using PUF support over sugar cane bagasse is that the former allows determination of fungal biomass which is not possible with the latter.

L'Institut de Recherche pour le Développement (IRD) a pour objectif la conduite de recherches avec des partenaires scientifiques des pays du Sud sur des thèmes importants pour le développement de ces pays. Depuis une quinzaine d'années, la dépollution et la valorisation des déchets agricoles et agro-industriels constituent l'un des trois principaux thèmes de recherche des microbiologistes regroupant leurs activités au sein d'un Programme de l'IRD intitulé "Utilisation de la biodiversité microbienne pour la valorisation des ressources tropicales". Ces recherches sont orientées d'une part vers les activités microbiennes anaérobies et la méthanisation, et d'autre part vers les processus microbiens dits de "fermentation en milieu solide" (FMS) impliquant principalement des champignons et des groupes bactériens tels que les bactéries lactiques. Ces deux orientations conditionnent le classement en trois grands groupes des résidus agricoles et agro-industriels pouvant constituer une source de pollution importante dans les pays du Sud et du Nord. Différents exemples de projets de recherche achevés ou en cours sont résumés en indiquant pour chacun d'eux (1) la nature du problème, (2) l'approche microbiologique du problème et (3) l'état de la valorisation pratique de ces résultats. Les recherches à l'IRD sur la méthanisation de sous-produits agricoles et agro-industriels tropicaux ont initialement été orientées vers la biodépollution. Les premiers travaux ont utilisé des consortiums microbiens non définis provenant de différents écosystèmes et adaptés aux produits à dépolluer. Ce n'est que récemment qu'un inoculum caractérisé a été utilisé avec succès. Ces travaux ont débouché soit sur la valorisation en milieu industriel, soit sur des essais en cours à l'échelle pilote... (D'après le résumé d'auteur)

La bagasse de manioc, un produit fibreux, utilisée seule ou mélangée avec de la bagasse de canne à sucre, est étudiée dans le but de connaître sa possibilité d'être employée comme support pour la production de #Pleurotus sajor-caju$ LPB 19 par fermentation en milieu solide. De nombreux facteurs sont ainsi évalués pour optimiser la production de carpophores : la température de fermentation, le pH initial et la composition du milieu d'imprégnation (glucose et NaCl). Les résultats obtenus indiquent que la bagasse de manioc est un excellent support pour la production de carpophores de #Pleurotus sajor-caju$. Les meilleurs résultats sont obtenus avec un milieu contenant un mélange de bagasse de manioc et de canne à sucre avec un rapport respectivement de 80% et 20%. Ce travail décrit une nouvelle approche pour la production de ce type de champignons avec ce support. (Résumé d'auteur)

Parmi les six souches d'#Aspergillus niger$ qui ont été criblées en milieu liquide, l'une d'entre elles, la souche LPB 21 a été retenue pour les études de valorisation de trois sous-produits agro-industriels en vue de produire de l'acide citrique par fermentation en milieu solide. La bagasse de manioc s'avère le meilleur substrat par rapport à la bagasse de canne à sucre et à l'éponge végétale. La production d'acide citrique a été de 13,64 g / 100 g de substrat sec. Le rendement s'élève à 41,78%. Les différents facteurs intervenant dans cette production ont fait l'objet d'une étude d'optimisation. Les meilleures conditions retenues ont été les suivantes : une humidité initiale de 50%, un pH initial de 2,0, une vitesse d'aération de 60 ml/min/colonne et une température d'incubation de 26°C. Dans ces conditions, la production d'acide citrique a été de 280 g/kg de substrat sec après 120 h de fermentation, ce qui correspond à un rendement de 70% (sur la base des sucres consommés). Les résultats rapportés dans cette communication précisent l'évolution du pH, de l'humidité, de la perte de poids en substrat, de l'utilisation de l'amidon et de la production de l'alpha-amylase au cours de la fermentation en milieu solide. (Résumé d'auteur)

La possibilité de produire des #Lentinula edodes$ (shiitake) sur des résidus agro-industriels, comme la bagasse de manioc et la bagasse de canne à sucre, par fermentation en milieu solide, est explorée. Les observations morphologiques effectuées sur des cultures en flacon ou en sac en plastique permettent d'estimer une bonne croissance sur ce type de substrat. La fructification et l'efficacité biologique du procédé sont déclarés satisfaisants. Les meilleurs résultats pour la production de basidiocarpes sont obtenus en employant un milieu contenant 80% de bagasse de manioc et 20% de bagasse de canne à sucre. Des résultats concernent la cinétique de la consommation de l'amidon contenu dans la bagasse de manioc parallèlement à celle de la synthèse de protéines. Pendant la biotransformation, une consommation d'amidon, estimée à 77,42% est associée à une synthèse de protéines trois fois plus abondante que celle couramment décrite. La fructification est achevée au bout de 60 jours d'incubation et a été diminué de 7 fois si l'on compare au procédé conventionnel de production sur des troncs de chênes. Ce temps de fuctification s'avère singulièrement réduit. Sa durée s'avère le septième de celle couramment décrite pour la culture faite sur résidus de chênes. Ces résultats ouvrent une nouvelle voie pour la production de #Lentinula$ en développant une nouvelle stratégie de culture sur un milieu innovant, un mélange de bagasse de manioc et de bagasse de canne à sucre. (Résumé d'auteur)

L'historique du programme de recherche mené à l'ORSTOM depuis vingt ans sur les fermentations en milieu solide a été brossé dans le but de faire une synthèse de nos travaux de recherche, au moment même où apparaît un regain d'intérêt international sur cette technique originale de culture de microorganismes. L'ORSTOM, Institut Français de Recherche Scientifique pour le Développement en Coopération, avait compris dès 1975 l'intérêt scientifique et les applications potentielles des fermentations en milieu solide (FMS). L'historique et l'évolution des fermentations en milieu solide ont été développées tout au long de cette présentation. Les activités de l'ORSTOM dans le domaine de l'enrichissement en protéines du manioc, du tourteau de coprah, de la valorisation des substrats lignocellulosiques, la production d'enzymes, des spores pour l'inoculation, les aspects physiologiques, les cultures sur support, la bioremédiation, les biopesticides, les métabolites secondaires, ont été analysées d'une manière critique afin de présenter les perspectives de cette technique de culture dans le domaine de la recherche pour les années à venir. (Résumé d'auteur)

A short term solution for the treatment of dairy waste water is discussed. Discharge rate is 500 m3/day with a high organic load (2,750 kg COD/day). Low capital investment (US $ 330,000) and operational (US $ 0.55/m3) costs were required which ought to be competitive with current market prices but within the official environmental norms imposed by the national agency SEDESOL. The problem was solved by remodelling existing lagooning facilities which were operating below the official norm. Local technology was used with the exception of aeration equipment. The system was made of a clarifier, an anaerobic lagoon, an intermediate aerobic lagoon and an effluent polishing lagoon with water hyacinth. Design and supervision was dones by UAM-Iztapalapa personnel. Construction and operation by the cheese factory "El Sauz, S.A. de C.V.". (Résumé d'auteur)

Research workers from UAMI and ORSTOM have being working for the last 15 years in an effort to study solid, liquid and gas fermentation systems in order to try to understand their potential and limitations for remedial environmental purposes. Among the main results to be cited: a) A comprehensive model of mycelial growth and metabolic activity, based on experimental evidence taken at microscopic level by image analysis, gasometric studies (on line barometric and gas analysis) and thermometry (heat and mass balances). b) As a result, a new scale-up strategy for solid and gas fermentation systems has been developed based on the conservation of heat and water content of the fermentation mash. c) The limitation of biomass activities in terms of surface and volume hindrances, as a fundamental constraint for densely packed bioreactors has been studied. d) Fundamental work has been done in relation to the biochemical and microbiological mechanisms of film and particle formation in anaerobic digesters. e) New strategies have been developed for the production and selection of mutant microbial strains specially adapted to solid fermentation systems. f) New approaches have been developed for reusing spent biomass and solid residues in agriculture and livestock production.

During the methanogenic fermentation of cassava peel, its composition (high starch content, high carbon: nitrogen ratio, presence of cyanogenic glucosides) usually results in excess acid production, nitrogen deficiency and the release of cyanide, which is highly toxic to methanogenic bacteria. The utilization of a plug flow digester (‘Transpaille’) solved the problem of acidification through localization of the acidogenic phase in the first half of the fermenter and the problem of nitrogen deficiency because a permanent liquid phase allowed nitrogen accumulation. No perturbation due to cyanide (5–6 mg/l) was observed in the fermenter. A fermentation yield of 0·661 m3 biogas/kg volatile solids (VS) was obtained with a loading rate of 3·6 kg VS/m3 day. Energy-saving calculations showed that a fermenter of 88 m3 is needed to produce the methane necessary for drying one ton of cassava meal.

L'alimentation artificielle constitue un aspect très important pour les poissons en élevage intensif. De ce fait, les qualités physiques et en particulier la stabilité à l'eau de l'aliment influencent grandement la production piscicole. Pour tenter de répondre à ces problèmes, une étude préliminaire sur la tenue à l'eau a été réalisée à la station expérimentale d'aquaculture de Layo. Ce travail a consisté à incorporer différents types de liants, disponibles en pays tropicaux, dans un aliment granulé en 3,5mm et 6mm de diamètres pour poissons, afin d'identifier un liant efficace permettant d'améliorer la stabilité à l'eau. Il ressort de cette expérience que l'utilisation de farine de blé (A1) donne des granulés d'excellentes qualités suivie du refus de farine de manioc (A3). De plus, cette étude fait apparaître qu'il existe une influence du diamètre sur le délitement des granulés. C.R.O. Published Alimentation artificielle, Poissons, Elevage, Pays tropical, Liants, Incorporation, Aliment composé, Stabilité à l'eau