Aeromonas hydrophila strains as biocatalysts for transglycosylation

Microbial transglycosylation is useful as a green alternative in the preparation of purine nucleosides and analogues, especially for those that display pharmacological activities. In a search for new transglycosylation biocatalysts, two Aeromonas hydrophila strains were selected. The substrate specificity of both micro-organisms was studied and, as a result, several nucleoside analogues have been prepared. Among them, ribavirin, a broad spectrum antiviral, and the well-known anti HIV didanosine, were prepared, in 77 and 62% yield using A. hydrophila CECT 4226 and A. hydrophila CECT 4221, respectively. In order to scale-up the processes, the reaction conditions, product purification and biocatalyst preparation were analyzed and optimized.Fil: Nóbile, Matías Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Terreni, Marco. Universita degli Studi di Pavia; ItaliaFil: Lewkowicz, Elizabeth Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Iribarren, Adolfo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. Universidad Nacional de Quilmes; Argentin

Citrobacter koseri immobilized on agarose beads for nucleoside synthesis: a potential biocatalyst for preparative applications

The biocatalyzed synthesis of purine nucleosides and their analogs is a case widely studied due to the high pharmaceutical interest of these compounds, providing the whole-cell biocatalysts, a useful tool for this purpose. Vidarabine and fludarabine are commercial examples of expensive bioactive nucleosides that can be prepared using a microbial transglycosylation approach. Citrobacter koseri whole-cells immobilized on agarose beads proved to be an interesting option to transform this biotransformation in a preparative process. The entrapment matrix provided a useful and resistant multipurpose biocatalyst regarding its stability, mechanical strength, microbial viability and reuse. Immobilized biocatalyst retained the initial activity for up to 1 year storage and after 10 years, the biocatalyst did not show cell leaking and still exhibited residual activity. In addition, the biocatalyst could be reused in batch 68 times keeping up to 50% of the initial biocatalytic activity and for at least 124 h in a continuous process.Fil: Nóbile, Matías Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Iribarren, Adolfo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Lewkowicz, Elizabeth Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentin

Exploring the production of citric acid with Yarrowia lipolytica using corn wet milling products as alternative low-cost fermentation media

The unconventional yeast Yarrowia lipolytica is known for its capability to synthesize different metabolites of industrial interest such as citric acid (CA). The numerous applications of CA trigger continuous research on improved production systems and substrates costs reduction. In this context, the present contribution explored the production of CA using chosen strains of Y. lipolytica in fermentation media formulated with low-cost and non-seasonal nutrient sources derived from the corn wet milling process, such as food grade corn syrups and corn steep liquor (CSL). Besides nutrient sources assay, the effect of carbon source concentration and C/N ratio was evaluated. In media formulated with high fructose syrup and CSL proper manipulation of the mentioned variables allowed attaining CA productions of up to 38 g/L in flasks culture. Moreover, the bioreactor scale-up allowed a 130%-increase in productivity and drastic fermentation time reduction. Overall, the combination of these low-cost nutrient sources of predictable composition derived from the corn processing industry that may be stored at room temperature seems attractive for CA production. The simplicity of the fermentation medium further makes it promising for higher-than-laboratory scale production of CA.Fil: Cavallo, Ema Claudia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Nóbile, Matías Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes; ArgentinaFil: Cerrutti, Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentina. Universidad de Buenos Aires. Facultad de Ingeniería; ArgentinaFil: Foresti, María Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Tecnología en Polímeros y Nanotecnología. Universidad de Buenos Aires. Facultad de Ingeniería. Instituto de Tecnología en Polímeros y Nanotecnología; Argentin

Streptomyces griseus: a new biocatalyst with N-oxygenase activity

Aromatic nitro compounds are key building blocks for many industrial syntheses and are also components of explosives, drugs and pesticides. Due to the environmentally unfriendly experimental conditions involved in their chemical syntheses, industrial processes would benefit from the use of biocatalysts. Among potentially useful enzymes, N-oxygenases, whose role is to oxygenate primary amines, are becoming relevant. These enzymes are involved in different secondary metabolic pathways in Streptomyces and in few other bacteria, forming part of the enzyme pools implicated in antibiotic synthesis. In this work, a group of Streptomyces strains, whose biomass was obtained from simple and novel culture media, were identified as new sources of N-oxygenase activity. Furthermore, the use of unspecific metabolic stimulation strategies allowed substantial improvements in the activity of whole cells as biocatalysts. It is remarkable the 6 to 50-fold increase in nitro compound yields compared to the biotransformation under standard conditions when Streptomyces griseus was the biocatalyst. In addition, biocatalyst substrate acceptance was studied in order to determine the biocatalytic potential of this enzyme.Fil: Nóbile, Matías Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Stricker, Abigail M.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Iribarren, Adolfo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Lewkowicz, Elizabeth Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; Argentin

N-oxygenation of amino compounds: early stages in its application to the biocatalyzed preparation of bioactive compounds

Among the compounds that contain unusual functional groups, nitro is perhaps one of the most interesting due to the valuable properties it confers on pharmaceuticals and explosives. Traditional chemistry has for many years used environmentally unfriendly strategies; in contrast, the biocatalyzed production of this type of products offers a promising alternative. The small family of enzymes formed by N-oxygenases allows the conversion of an amino group to a nitro through the sequential addition of oxygen. These enzymes also make it possible to obtain other less oxidized N-O functions, such as hydroxylamine or nitroso, present in intermediate or final products. The current substrates on which these enzymes are reported to work encompass a few aromatic molecules and sugars. The unique characteristics of N-oxygenases and the great economic value of the products that they could generate, place them in a position of very high scientific and industrial interest. The most important and best studied N-oxygenases will be presented here.Fil: Nóbile, Matías Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres". Grupo Vinculado al INGEBI- Laboratorio de Biocatálisis y Biotransformaciones - LBB - UNQUI; ArgentinaFil: Stricker, Abigail M.. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Marchesano, Lucas. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología; ArgentinaFil: Iribarren, Adolfo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres". Grupo Vinculado al INGEBI- Laboratorio de Biocatálisis y Biotransformaciones - LBB - UNQUI; ArgentinaFil: Lewkowicz, Elizabeth Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigación en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres". Grupo Vinculado al INGEBI- Laboratorio de Biocatálisis y Biotransformaciones - LBB - UNQUI; Argentin

Organophosphorus compounds biodegradation by novel bacterial isolates and their potential application in bioremediation of contaminated water

Organophosphorus compounds (OPs), the major pesticides used worldwide, comprise an environmental hazard due to their harmful toxicity. Aimed to develop a bioreactor to remediate OPs contaminated wastewater, bacteria isolated from contaminated soils were identified and their ability to degrade OPs assessed, resulting in two main isolates, Sphingomonas sp. and Brevundimonas sp. Their OP degrading activities were characterized in terms of temperature, pH and substrates acceptance, resulting in high degradation rates at 60 °C, pH 10 and towards bulky OPs such as coroxon, coumaphos, and chlorpyrifos. Sphingomonas sp. cells were immobilized and 75.4% degradation of 0.15 mM chlorpyrifos was achieved after 21 days by immobilized cells in batch system, while this OP was completely degraded within 17 h when the biocatalyst is settled in a packed bed bioreactor, with a reusability of 8 cycles. These results suggest the potential application of this system in the bioremediation of contaminated wastewater.Fil: Santillan, Julia Yamila. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Química. Laboratorio de Biotransformaciones; ArgentinaFil: Rojas, Natalia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Ingeniería Genética y Biología Molecular y Celular; ArgentinaFil: Ghiringhelli, Pablo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Laboratorio de Ingeniería Genética y Biología Molecular y Celular; ArgentinaFil: Nóbile, Matías Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Química. Laboratorio de Biotransformaciones; ArgentinaFil: Lewkowicz, Elizabeth Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Química. Laboratorio de Biotransformaciones; ArgentinaFil: Iribarren, Adolfo Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Quilmes. Departamento de Ciencia y Tecnología. Área Química. Laboratorio de Biotransformaciones; Argentin