ImprovingkLa determination in fungal fermentation, taking into account electrode response time

Badino, Alberto Colli; Facciotti, Maria Cândida Reginato; Schmidell, Willibaldo

doi:10.1002/1097-4660(200006)75:6<469::aid-jctb236>3.0.co;2-4

Cited by 46 publications

(30 citation statements)

References 12 publications

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“…The higher kLa (0.0197 1/s) value obtained for an airflow of 1.0 vvm, was around five times smaller than the probe delay constant (0.1081 1/s, determined experimentally). Therefore, as suggested by Schmidell [17], there is no need for kLa value adjustments as a function of the probe response time [31]. Table 1 presents the values of kLa and other hydrodynamic parameters, obtained in the literature for different bioreactor designs.…”

Section: Discussionmentioning

confidence: 99%

Airlift Bioreactor Fluid-Dynamic Characterizationfor the Cultivation of Shear Stress Sensitivemicroorganisms

Rossi

Nascimento

Giachini

et al. 2015

JBT

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ISSN 2 3 4 8 -6 2 0 1 V o l u m e 5 N u m b e r 2 J o u r n a l o f A d v a n c e s i n B i o t e c h n o l o g y 639 | P a g e c o u n c i l f o r I n n o v a t i v e R e s e a r c h F e b r u a r y 2 0 1 6 w w w . ABSTRACTAirlift bioreactors are considered very efficient for aerobic cultivation of microorganisms. In particular, for the cultivation of filamentous fungi, where low shear rates may be required. In this context, the main aim of this study was to design an airlift bioreactor built with an external loop, adequate for biomass production of microbial organisms, including ectomycorrhizal fungi. A 5-L airlift bioreactor was constructed and experimental studies performed under an air-salt solution system (0.15 mol/L NaCl), in order to characterize the reactor´s fluid-dynamic in relation to the superficial gas velocity (Ug) in the range of 0.001 to 0.020 m/s. In order to evaluate the performance of the reactor, a preliminary assay was conducted with the ectomycorrhizal fungus Rhizopogon nigrescens. Better gas separation reflected in better liquid circulation and higher oxygen transfer (0.0197 1/s at 1 vvm) when compared to an operating, 2.3-L prototype airlift. According to this study, volumetric coefficients for oxygen transfer (kLa) up to 0.020 1/s (specific airflow rates of 1.0 vvm) are sufficient to promote the growth of shear stress sensitive microorganisms, such as ectomycorrhizal fungi.

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Section: Discussionmentioning

confidence: 99%

Airlift Bioreactor Fluid-Dynamic Characterizationfor the Cultivation of Shear Stress Sensitivemicroorganisms

Rossi

Nascimento

Giachini

et al. 2015

JBT

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“…The volumetric mass transfer coefficient (k L a) was determined by dynamic gassing-in method as reported [32][33][34]. Two DO inductors were used simultaneously for two independent measurements.…”

Section: Calculation Of Kinetic Parametersmentioning

confidence: 99%

Enhancement of Cellulase and Xylanase Production Using pH-Shift and Dissolved Oxygen Control Strategy with Streptomyces griseorubens JSD-1

Zhang

Luo

Chu

et al. 2015

Appl Biochem Biotechnol

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In this study, the production of cellulase and xylanase by Streptomyces griseorubens JSD-1 was improved by integrating the pH-shift and dissolved oxygen (DO)-constant control strategies. The pH-shift control strategy was carried out by analyzing the specific cell growth rate (μ) and specific enzyme formation rate (Q p) of S. griseorubens JSD-1. The pH was controlled at 8.0 during the first 48 h to maintain high cell growth, which then shifted to 7.5 after 48 h to improve the production of cellulase and xylanase. Using this method, the maximum activities of cellulase, xylanase, and filter paper enzyme (FPase) increased by 47.9, 29.5, and 113.6 %, respectively, compared to that obtained without pH control. On the basis of pH-shift control, the influence of DO concentrations on biomass and enzyme production was further investigated. The maximum production of cellulase, xylanase, and FPase reached 114.38 ± 0.96 U mL(-1), 330.57 ± 2.54 U mL(-1), and 40.11 ± 0.38 U mL(-1), which were about 1.6-fold, 0.6-fold, and 3.2-fold higher than that of neutral pH without DO control conditions. These results supplied a functional approach for improving cellulase and xylanase production.

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“…The method adapted from Shuler and Kargi [20] and Badino et al [21] for determination of k L a in a non-fermentative system using steady-state or static gassing-out technique was done by lowering the oxygen concentration in the solution.…”

Section: Fermentation In 2-l Stirred Tank Reactormentioning

confidence: 99%

“…Agitation intensity may affect both fungal morphology [27][28][29][30] and mass transfer in the bioreactor [21,31]. In many fungal fermentation, a high agitation rate is necessary to provide adequate mixing and mass transfer, especially when the fungal cells grow in a freely dispersed form, which results in a non-Newtonian broth and a high apparent viscosity.…”

Section: Effect Of Agitationmentioning

confidence: 99%

Effect of Agitation and Aeration Rates on Chitinase Production Using Trichoderma virens UKM1 in 2-l Stirred Tank Reactor

Abd‐Aziz

Fernandez

Salleh

et al. 2008

Appl Biochem Biotechnol

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Shrimps have been a popular raw material for the burgeoning marine and food industry contributing to increasing marine waste. Shrimp waste, which is rich in organic compounds is an abundant source of chitin, a natural polymer of N-acetyl-D-glucosamine (GluNac), a reducing sugar. For this respect, chitinase-producing fungi have been extensively studied as biocontrol agents. Locally isolated Trichoderma virens UKM1 was used in this study. The effect of agitation and aeration rates using colloidal chitin as control substrate in a 2-l stirred tank reactor gave the best agitation and aeration rates at 200 rpm and 0.33 vvm with 4.1 U/l per hour and 5.97 U/l per hour of maximum volumetric chitinase activity obtained, respectively. Microscopic observations showed shear sensitivity at higher agitation rate of the above system. The oxygen uptake rate during the highest chitinase productivity obtained using sun-dried ground shrimp waste of 1.74 mg of dissolved oxygen per gram of fungal biomass per hour at the kappaL a of 8.34 per hour.

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ImprovingkLa determination in fungal fermentation, taking into account electrode response time

Cited by 46 publications

References 12 publications

Airlift Bioreactor Fluid-Dynamic Characterizationfor the Cultivation of Shear Stress Sensitivemicroorganisms

Airlift Bioreactor Fluid-Dynamic Characterizationfor the Cultivation of Shear Stress Sensitivemicroorganisms

Enhancement of Cellulase and Xylanase Production Using pH-Shift and Dissolved Oxygen Control Strategy with Streptomyces griseorubens JSD-1

Effect of Agitation and Aeration Rates on Chitinase Production Using Trichoderma virens UKM1 in 2-l Stirred Tank Reactor

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