title: Evaluation of hexose and pentose in pre-cultivation of Candida guilliermondii on the key enzymes for xylitol production in sugarcane hemicellulosic hydrolysate.
abstract: The evaluation of hexose and pentose in pre-cultivation of Candida guilliermondii FTI 20037 yeast on xylose reductase (XR) and xylitol dehydrogenase (XDH) enzymes activities was performed during fermentation in sugarcane bagasse hemicellulosic hydrolysate. The xylitol production was evaluated by using cells previously growth in 30.0 gl(-1) xylose, 30.0 gl(-1) glucose and in both sugars mixture (30.0 gl(-1) xylose and 2.0 gl(-1) glucose). The vacuum evaporated hydrolysate (80 gl(-1)) was detoxificated by ion exchange resin (A-860S; A500PS and C-150-Purolite®). The total phenolic compounds and acetic acid were 93.0 and 64.9%, respectively, removed by the resin hydrolysate treatment. All experiments were carried out in Erlenmeyer flasks at 200 rpm, 30°C. The maximum XR (0.618 Umg (Prot) (-1)) and XDH (0.783 Umg (Prot) (-1)) enzymes activities was obtained using inoculum previously growth in both sugars mixture. The highest cell concentration (10.6 gl(-1)) was obtained with inoculum pre-cultivated in the glucose. However, the xylitol yield and xylitol volumetric productivity were favored using the xylose as carbon source. In this case, it was observed maximum xylose (81%) and acetic acid (100%) consumption. It is very important to point out that maximum enzymatic activities were obtained when the mixture of sugars was used as carbon source of inoculum, while the highest fermentative parameters were obtained when xylose was used.
authors.affiliation: Departamento de Biotecnologia, Universidade de São Paulo, Escola de Engenharia de Lorena, Estrada Municipal do Campinho s/no, P.O. Box 116, CEP 12602-810, Lorena, São Paulo, Brazil. priscilavaz@debiq.eel.usp.br
authors.forename: Priscila Vaz
authors.initials: PV
authors.lastname: de Arruda
authors.forename: Rita de Cássia Lacerda Brambilla
authors.initials: Rde C
authors.lastname: Rodrigues
authors.forename: Débora Danielle Virgínio
authors.initials: DD
authors.lastname: da Silva
authors.forename: Maria das Graças de Almeida
authors.initials: Md
authors.lastname: Felipe
mesh_terms: D019342:Acetic Acid / Q000737:chemistry; D000449:Aldehyde Reductase / Q000378:metabolism; D019149:Bioreactors; D002175:Candida / Q000201:enzymology* / Q000254:growth & development; D002482:Cellulose / Q000378:metabolism*; D003470:Culture Media; D050542:D-Xylulose Reductase / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D006868:Hydrolysis; D010636:Phenols / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism*; D011312:Pressure; D031786:Saccharum / Q000378:metabolism*; D014993:Xylitol / Q000096:biosynthesis; D014994:Xylose / Q000378:metabolism
chemical_list: D003470:Culture Media; D010636:Phenols; D011134:Polysaccharides; C007916:hemicellulose; D002482:Cellulose; C027433:bagasse; D014994:Xylose; D000449:Aldehyde Reductase; D050542:D-Xylulose Reductase; D005947:Glucose; D019342:Acetic Acid; D014993:Xylitol