Glucose-6-phosphate dehydrogenase and xylitol production by Candida guilliermondii FTI 20037 using statistical experimental design

Gurpilhares, Daniela B.; Pessoa, Adalberto; Roberto, Inês Conceição

doi:10.1016/j.procbio.2005.08.008

Cited by 18 publications

(17 citation statements)

References 31 publications

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“…24 The supernatants were assayed for enzyme (XR and XD) activities, and total protein concentration was determined according to Lowry et al 25 using bovine serum albumin (BSA) as standard. Determination of K L a, xylose, xylitol and cell concentrations K L a was determined by the 'gassing-out' method of Pirt.…”

Section: Cell Disruptionmentioning

confidence: 99%

Profiles of xylose reductase, xylitol dehydrogenase and xylitol production under different oxygen transfer volumetric coefficient values

Branco

Santos

Sarrouh

et al. 2008

J of Chemical Tech & Biotech

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BACKGROUND: Xylitol is a sugar alcohol (polyalcohol) with many interesting properties for pharmaceutical and food products. It is currently produced by a chemical process, which has some disadvantages such as high energy requirement. Therefore microbiological production of xylitol has been studied as an alternative, but its viability is dependent on optimisation of the fermentation variables. Among these, aeration is fundamental, because xylitol is produced only under adequate oxygen availability. In most experiments with xylitol-producing yeasts, low oxygen transfer volumetric coefficient (K L a) values are used to maintain microaerobic conditions. However, in the present study the use of relatively high K L a values resulted in high xylitol production. The effect of aeration was also evaluated via the profiles of xylose reductase (XR) and xylitol dehydrogenase (XD) activities during the experiments.

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Section: Cell Disruptionmentioning

confidence: 99%

Profiles of xylose reductase, xylitol dehydrogenase and xylitol production under different oxygen transfer volumetric coefficient values

Branco

Santos

Sarrouh

et al. 2008

J of Chemical Tech & Biotech

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“…After that, the pH was adjusted to approximately pH 4.5 or 7.5 by addition of NaOH pellets, and the precipitate was removed by centrifugation (1,100£g, 20 min). No nutrient was added to the hydrolysate [10] and to avoid degradation of xylose during autoclavation, the hydrolysate-based medium was not sterilized. Fermentations were performed in 500 ml Erlenmeyer Xasks containing 200 ml of medium.…”

Section: Medium and Fermentation Conditionsmentioning

confidence: 99%

“…Besides, this cofactor is also needed for biomass formation. Consequently, G6PD is an important enzyme for the bioconversion of xylose to xylitol, since this enzyme is the Wrst enzyme of the PPP and yield cofactors NADPH for the xylose reduction [10]. Further, a minimum xylose concentration has been shown to be critical for yeast growth and xylitol formation.…”

Section: Biomass and Xylitol Productionmentioning

confidence: 99%

The behavior of key enzymes of xylose metabolism on the xylitol production by Candida guilliermondii grown in hemicellulosic hydrolysate

Gurpilhares

Hasmann

Pessoa

et al. 2008

J Ind Microbiol Biotechnol

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A variety of raw materials have been used in fermentation process. This study shows the use of rice straw hemicellulosic hydrolysate, as the only source of nutrient, to produce high added-value products. In the present work, the activity of the enzymes xylose reductase (XR); xylitol dehydrogenase (XD); and glucose-6-phosphate dehydrogenase (G6PD) during cultivation of Candida guilliermondii on rice straw hemicellulosic hydrolysate was measured and correlated with xylitol production under different pH values (around 4.5 and 7.5) and initial xylose concentration (around 30 and 70 g l(-1)). Independent of the pH value and xylose concentration evaluated, the title of XD remained constant. On the other hand, the volumetric activity of G6PD increased whereas the level of XR decreased when the initial xylose concentration was increased from 30 to 70 g l(-1). The highest values of xylitol productivity (Q (P) approximately 0.40 g l(-1)) and yield factor (Y (P/S) approximately 0.60 g g(-1)) were reached at highest G6PD/XR ratio and lowest XR/XD ratio. These results suggest that NADPH concentrations influence the formation of xylitol more than the activity ratios of the enzymes XR and XD. Thus, an optimal rate between G6PD and XR must be reached in order to optimize the xylitol production.

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“…Lignocellulosics are an abundant and inexpensive source of carbohydrates that can be used to produce high-value chemicals (Carvalho et al, 2002;. Biotechnological production of xylitol could be economically attractive using hemicellulosic hydrolysates as potential substrates, instead of pure xylose, to reduce the cost of production (Gurpilhares et al, 2005;Mussato & Roberto, 2004;Pessoa Júnior et al, 1996). Hemicellulose is a plant cell wall polysaccharide and, in some plants, comprises up to 40% of the total dry material.…”

Section: Introductionmentioning

confidence: 99%

Xylose production from sugarcane bagasse by surface response methodology

Paiva

Maldonade

Scamparini

2009

Rev. bras. eng. agríc. ambient.

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The aim of this study was to optimize the production of xylose from sugarcane bagasse. The hydrolysis process was carried out to evaluate the effect of temperature and sulphuric acid concentration on the xylose production at 18, 30, and 50 min of hydrolysis. A Central Composite Rotatable Design (CCRD) was used to study two process variables, temperature (111.5; 114.0; 120.0; 126.0 and 128.5°C) and sulphuric acid concentration (0.20; 0.70; 1.90; 3.10 and 3.60% v v -1 ). Sulphuric acid had a greater influence on the hydrolysis process than temperature. At concentrations of sulphuric acid higher than 3.10% (v v -1 ), raising temperature had little influence on the yield of xylose production. The best condition to obtain xylose (266.73 mg g -1 of dry bagasse) was at 18 min of reaction, at 126°C and 3.10% (v v -1 ) of sulphuric acid, representing 96.0% of the theoretical maximum.

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Glucose-6-phosphate dehydrogenase and xylitol production by Candida guilliermondii FTI 20037 using statistical experimental design

Cited by 18 publications

References 31 publications

Profiles of xylose reductase, xylitol dehydrogenase and xylitol production under different oxygen transfer volumetric coefficient values

Profiles of xylose reductase, xylitol dehydrogenase and xylitol production under different oxygen transfer volumetric coefficient values

The behavior of key enzymes of xylose metabolism on the xylitol production by Candida guilliermondii grown in hemicellulosic hydrolysate

Xylose production from sugarcane bagasse by surface response methodology

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