Production and toxicity of γ-decalactone and 4-hydroxydecanoic acid from Rhodotorula aurantiaca

Poster (2009)

The objective of this study was to compare the production of γ- decalactone in different scales and to study the effects of 4- hydroxydecanoic acid and γ-decalactone on the growth of R. aurantiaca. The ... [more ▼]

The objective of this study was to compare the production of γ- decalactone in different scales and to study the effects of 4- hydroxydecanoic acid and γ-decalactone on the growth of R. aurantiaca. The effect of gum tragacanth on the production of γ-decalactone by R. aurantiaca was evaluated. [less ▲]

La conservation du poisson au Senegal : utilisation d’une souche locale de Lactococcus lactis

in Cahiers Agricultures (2009), 18(4), 337-342

L’effet antimicrobien du surnageant de culture neutralisé (SCN) bactéricide issu de Lactococcus lactis CWBI-B1410 d’origine locale, utilisé seul ou en combinaison avec du chlorure de sodium (NaCl) comme ... [more ▼]

L’effet antimicrobien du surnageant de culture neutralisé (SCN) bactéricide issu de Lactococcus lactis CWBI-B1410 d’origine locale, utilisé seul ou en combinaison avec du chlorure de sodium (NaCl) comme conservateurs, a été évalué sur poissons maigre (Pomadasys jubelini), moyennement gras (Polydactylus quadrifilis) et gras (Arius heudeloti)] au Sénégal. Les poissons ont été achetés dans un marché local, éviscérés, lavés avec de l’eau de robinet potable, puis filetés. Cent millilitres de SCN de CWBI-B1410 non salé et salé ont été additionnés dans 100 grammes de filets (concentration finale de NaCl entre 0 et 7 %) dans des bocaux en verre conservés à 10 °C. L’évolution de la flore mésophile totale (FMT) des filets a été comparée à celles de filets traités avec du SCN non salé et salé (concentration finale de NaCl entre 0 et 7 %), issu de L. lactis LMG6890 ne produisant pas de bactériocine. Un niveau de FMT de 106 micro-organismes par gramme (ufc/g) a été considéré comme la fin de la durée de conservation. Le niveau de la flore mésophile totale des filets crus atteignait 5,74 log ufc/g. L’ajout de SCN de CWBI-B1410 dans les filets de poisson maigre réduit la flore mésophile totale de 1 log ufc/g et stabilise la flore pendant 4 jours – correspondant à la durée de conservation de ces filets a` 10 °C, contre 0,5 jour pour le contrôle négatif. L’addition de SCN de CWBIB1410 salé sur les poissons (NaCl, 7 %) réduit davantage la FMT et retarde sa croissance à 10°C, entraînant comme résultat l’augmentation de la durée de conservation de respectivement 12, 7,5 et 8 jours pour le poisson maigre, moyennement gras et gras. Ces résultats suggèrent que cette stratégie peut constituer un moyen convenable d’améliorer la conservation des produits halieutiques tropicaux. [less ▲]

Aspects microbiologiques de la production par fermentation solide des endo-β-1,4-xylanases de moisissures : le cas de Penicillium canescens

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2009), 13(2), 281-294

Production of xylanases by Penicillium canescens 10-10c is the research object in Walloon Center of Industrial Biology. Previous works used submerged or liquid fermentation. The actual works are oriented ... [more ▼]

Production of xylanases by Penicillium canescens 10-10c is the research object in Walloon Center of Industrial Biology. Previous works used submerged or liquid fermentation. The actual works are oriented more and more towards solid fermentation from agricultural or agro-alimentary residues. In addition to the valorization of these residues, solid-state fermentation reaches an increasingly significant interest in various other fields like the biological breakdown of the solid residues, the bioremediation of the organic pollutants in the grounds and the reduction of the air pollution by the biofiltration. Xylanase is an industrial enzyme used in general in extraction and clarification processes. P. canescens can produce an activity of it, particularly in its balanced forms of xylanases, beta-xylosidase and arabinosidase, and not contaminated by cellulolytic and amylolytic activities. It is a hyper producing strain of xylanase. The production rate is one of the highest in literature (535 U.ml-1 and 9,632 U.g-1 in Erlenmeyer flasks, in submerged and solid state fermentation, respectively). The biobleaching activity of the cellulose pulp by the purified enzyme is higher than a commercial preparation of xylanases from Trichoderma longibrachiatum used industrially. It has a complete hydrolysis degree of 40% (on glucuronoxylan) and 35% (on arabinoxylan) at 55°C and at pH of 5.9. These characteristics lead to many industrial applications of this enzyme. That is why the optimization of its production by the solid-state fermentation at the laboratory scale in order to define a policy for the industrial transposition later is carried out. This article presents a summary of the scientific literature on this subject. [less ▲]

Xylanase Production by Penicillium canescens on Soya Oil Cake in Solid-State Fermentation.

in Applied biochemistry and biotechnology (2009), (2),

There is an increasing interest for the organic residues from various sectors of agriculture and industries over the past few decades. Their application in the field of fermentation technology has ... [more ▼]

There is an increasing interest for the organic residues from various sectors of agriculture and industries over the past few decades. Their application in the field of fermentation technology has resulted in the production of bulk chemicals and value-added products such as amino acid, enzymes, mushroom, organic acids, single-cell protein, biologically active secondary metabolites, etc. (Ramachandran et al., Bioresource Technology 98:2000–2009, 2007). In this work, the production of extracellular xylanase by the fungus Penicillium canescens was investigated in solid-state fermentation using five agro-industrial substrates (soya oil cake, soya meal, wheat bran, whole wheat bran, and pulp beet). The best substrate was the soya oil cake. In order to optimize the production, the most effective cultivation conditions were investigated in Erlenmeyer flasks and in plastic bags with 5 and 100 g of soya oil cake, respectively. The initial moisture content, initial pH, and temperature of the culture affected the xylanase synthesis. The optimal fermentation medium was composed by soya oil cake crushed to 5 mm supplemented with 3% and 4% (w/w) of casein peptone and Na2HPO4.2H2O. After 7 days of incubation at 30 °C and under 80% of initial moisture, a xylanase production level of 18,895±778 U/g (Erlenmeyer flasks) and 9,300± 589 U/g (plastic bags) was reached. The partially purified enzyme recovered by ammonium sulfate fractionation was completely stable at freezing and refrigeration temperatures up to 6 months and reasonably stable at room temperature for more than 3 months. [less ▲]

Investigation of the effect of different extracellular factors on the lipase production by Yarrowia lipolityca on the basis of a scale-down approach

in JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY (2008), 35(9), 1053-1059

The influence of three extracellular factors (namely, the methyl oleate dispersion in the broth, the dissolved oxygen variations, and the pH fluctuation) on the lipase production by Y. lipolytica in batch ... [more ▼]

The influence of three extracellular factors (namely, the methyl oleate dispersion in the broth, the dissolved oxygen variations, and the pH fluctuation) on the lipase production by Y. lipolytica in batch bioreactor has been investigated in different scale-down apparatus. These systems allow to reproduce the hydrodynamic phenomena encountered in large-scale equipments for the three specified factors. The effects of the extracellular factors have been observed at three distinct levels: the microbial growth, the extracellular lipase production, and the induction of the gene LIP2 encoding for the main lipase of Y. lipolytica. Among the set of environmental factors investigated, the dissolved oxygen fluctuations generated in a controlled scale-down reactor (C-SDR) have led to the more pronounced physiological effect by decreasing the LIP2 gene expression level. The other environmental factors observed in a partitioned scale-down reactor, i.e., the methyl oleate dispersion and the pH fluctuations, have led to a less severe stress traduced only by a decrease of the microbial yield and thus of the extracellular lipase specific production rate. [less ▲]

Environmental oscillations occuring in small-scale bioreactors during an E. coli BL21 fedbatch culture

Conference (2008, May 04)

Study on mass transfer of isopropylbenzene and oxygen in a two-phase partitioning bioreactor in the presence of silicone oil.

Poster (2008, May)

Sugar beet leaves valorisation through green notes production from linseed oil.

Poster (2008)

Characterization of lactic acid bacteria isolated from poultry farms in Senegal

in African Journal of Biotechnology (2008), 7(12), 2006-2012

The group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known and these organisms have been characterized extensively by using different techniques. In this study ... [more ▼]

The group that includes the lactic acid bacteria is one of the most diverse groups of bacteria known and these organisms have been characterized extensively by using different techniques. In this study, thirty lactic acid bacterial strains were isolated from soils chicken faeces and feathers. A total of nineteen isolates were obtained and by sequential screening for catalase activity and Gram-staining, eight were determined to be LAB out of which six were established to be homofermentative by the gel plug test. Five isolates were identified by use of the API 50CHL kit and four Lactobacilli strains and one Lactococci strain were selected to study their growth and lactic acid production profiles in a time course experiment. The Lactobacilli strains, both isolated from faeces, produced higher amounts of cells and lactic acid from soils as compared to the lactococci strain isolated from feathers. L (+)-lactic acid is the only optical isomer for use in pharmaceutical and food industries because is only adapted to assimilate this form. The optical isomers of lactic acid were examined by L (+) and D (-) lactate dehydrogenase kit. Lactobacilli strains produced combination of both optical isomers of lactic acid. Among them, Lactobacillus casei subsp. casei produced the low amount of D (-)-lactic (2%). The optimum rates of glucose for lactic acid production by Lactobacillus strains were 180 and 120 g/l for Lactobacillus plantarum and Lactobacillus paraplantarum, respectively. [less ▲]

Improvement of xylanase production by Penicillium canescens 10-10c in solid-state fermentation

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2008)