title: Contribution of tris buffer on xylitol enzymatic production.
abstract: Xylitol enzymatic production can be an alternative to chemical and microbial processes, because of advantages like higher conversion efficiency. However, for an adequate conversion, it is necessary to investigate the effect of many parameters, such as buffer initial concentration, pH, temperature, agitation, etc. In this context, the objective of this work was to evaluate xylitol enzymatic production under different Tris buffer initial concentrations in order to determine the best condition for this parameter to begin the reaction. The best results were obtained when Tris buffer initial concentration was 0.22 M, reaching 0.31 g L(-1) h(-1) xylitol volumetric productivity with 99% xylose-xylitol conversion efficiency. Although the increase in buffer concentration allowed better pH maintenance, it hindered the catalysis. The results demonstrate that this bioreaction is greatly influenced by involved ions concentrations.
authors.affiliation: Grupo de Microbiologia Aplicada e Bioprocessos, Departamento de Biotecnologia, Universidade de São Paulo-Escola de Engenharia de Lorena, Lorena, São Paulo, Brazil. ricardo@debiq.eel.usp.br
authors.forename: Ricardo de Freitas
authors.initials: Rde F
authors.lastname: Branco
authors.forename: Silvio S
authors.initials: SS
authors.lastname: Silva
mesh_terms: D000449:Aldehyde Reductase / Q000737:chemistry*; D002021:Buffers; D002175:Candida / Q000201:enzymology; D005656:Fungal Proteins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D014325:Tromethamine / Q000032:analysis*; D014993:Xylitol / Q000737:chemistry*; D014994:Xylose / Q000737:chemistry
chemical_list: D002021:Buffers; D005656:Fungal Proteins; D014325:Tromethamine; D014994:Xylose; D000449:Aldehyde Reductase; D014993:Xylitol