Kinetic and thermodynamic aspects of glucose-6-phosphate dehydrogenase activity and synthesis

Rossi, F.; Ribeiro, Marcela Zanella; Converti, Attílio; Vítolo, Michele; Pessoa, Adalberto

doi:10.1016/s0141-0229(02)00242-9

Cited by 23 publications

(15 citation statements)

References 26 publications

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“…3) to estimate the thermodynamic parameters of both growth and its inactivation, assuming that the latter phenomenon is the result of an equilibrium favoured by a temperature increase. As expected, the enthalpy variation of thermal inactivation equilibrium (90.5 kJ/mol) was higher than the activation enthalpy of growth (64.7 kJ/mol) and both values compare with those estimated for other bioprocesses and enzymatic systems [5,16,18]. These results are consistent with the peculiar sensitivity of S. platensis growth to temperature, and with the hypothesis that the growth rate could be limited, at high tempera- Theoretical biotic removals estimated assuming the S. platensis composition reported by Cornet et al [8] c Abiotic removals calculated as the difference between experimental and theoretical biotic removals ture, by reversible inactivation of a growth-controlling enzyme [16].…”

Section: Effect Of Temperaturesupporting

confidence: 81%

Nitrate and phosphate removal by Spirulina platensis

Lodi

Binaghi

Solisio

et al. 2003

J IND MICROBIOL BIOTECHNOL

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The cyanobacterium Spirulina platensis was used to verify the possibility of employing microalgal biomass to reduce the contents of nitrate and phosphate in wastewaters. Batch tests were carried out in 0.5 dm3 Erlenmeyer flasks under conditions of light limitation (40 micromol quanta m(-2) s(-1)) at a starting biomass level of 0.50 g/dm3 and varying temperature in the range 23-40 degrees C. In this way, the best temperature for the growth of this microalga (30 degrees C) was determined and the related thermodynamic parameters were estimated. All removed nitrate was used for biomass growth (biotic removal), whereas phosphate appeared to be removed mainly by chemical precipitation (abiotic removal). The best results in terms of specific and volumetric growth rates (mu=0.044 day(-1), Qx=33.2 mg dm(-3) day(-1)) as well as volumetric rate and final yield of nitrogen removal (Q(N-NO3-)=3.26 mg dm(-3) day(-1), Y(N-NO3-)=0.739) were obtained at 30 degrees C, whereas phosphorus was more effectively removed at a lower temperature. In order to simulate full-scale studies, batch tests of nitrate and phosphate removal were also performed in 5.0 dm3 vessels (mini-ponds) at the optimum temperature (30 degrees C) but increasing the photon fluence rate to 80 micromol quanta m(-2) s(-1) and varying the initial biomass concentration from 0.25 to 0.86 g/dm3. These additional tests demonstrated that an increase in the inoculum level up to 0.75 g/dm3 enhanced both NO3- and PO4(3-) removal, confirming a strict dependence of these processes on biomass activity. In addition, the larger surface area of the ponds and the higher light intensity improved removal yields and kinetics compared to the flasks, particularly concerning phosphorus removal (mu=0.032-0.050 day(-1), Qx=34.7-42.4 mg dm(-3) day(-1), Q(N-NO3-)=3.24-4.06 mg dm(-3) day(-1), Y(N-NO3-)=0.750-0.879, Q(P-PO4(3-))=0.312-0.623 mg dm(-3) day(-1), and Y(P-PO4(3-))=0.224-0.440).

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Section: Effect Of Temperaturesupporting

confidence: 81%

Nitrate and phosphate removal by Spirulina platensis

Lodi

Binaghi

Solisio

et al. 2003

J IND MICROBIOL BIOTECHNOL

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“…The mixture was maintained below 10°C throughout the process. Cell debris and glass beads were removed by centrifugation (3025g, 20 min, 6°C) and the supernatant was used for determinations of enzymatic activity (Miguel et al, 2003;Rossi, Ribeiro, Converti, Vitolo, & Pessoa, 2003).…”

Section: Cell Disruptionmentioning

confidence: 99%

Effect of carbon:nitrogen ratio (C:N) and substrate source on glucose-6-phosphate dehydrogenase (G6PDH) production by recombinant Saccharomyces cerevisiae

Danesi

Miguel

Rangel-Yagui

et al. 2006

Journal of Food Engineering

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“…The mechanism of thermal inactivation for G6PD from Saccharomyces cerevisiae has been studied and it was found that at temperatures higher than T = 308 K, the half-life time values are very low and the enzyme is denatured rapidly [4]. Thermodynamic and kinetic studies of the synthesis and activity of G6PD from S. cerevisiae have been reported [5], however similar results were not found for G6PD from L. mesenteroides. Although there are some kinetic and thermodynamic data for the G6PD activity with NADP ox , the experimental work is old and not detailed, and the results are difficult to compare systematically [6,7].…”

Section: Abbreviationsmentioning

confidence: 95%