The growth behaviour of Thermus aquaticus in continuous cultivation

Cometta, S.; Sonnleitner, Bernhard; Fiechter, Armin

doi:10.1007/bf00499509

Cited by 42 publications

(13 citation statements)

References 18 publications

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“…This is comparable to that reported by Frankena et al (1985) where a maximum growth yield of 90.9 g cells/mol glucose and a maintenance coefficient of 0.14 mmol glucose/h/g cells was obtained for non-protease producing Bacillus licheniformis grown in a glucose-limited chemostat at 378C. In fact, pure cultures of fast growing thermophilic aerobes demonstrate high maintenance requirements possibly due to the high turnover of cell material (Cometta et al, 1982;Kuhn et al, 1980). The specific rate of glucose consumption (q glucose ) increased linearly up to D ¼ 0.87/h above which the q glucose began to increase (Fig.…”

Section: Efficiency Of Carbon Conversion In Glucose-limited Culture Asupporting

confidence: 84%

The use of multi‐parameter flow cytometry to study the impact of limiting substrate, agitation intensity, and dilution rate on cell aggregation during Bacillus licheniformis CCMI 1034 aerobic continuous culture fermentations

Silva

Reis

Kent

et al. 2005

Biotech & Bioengineering

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The main objective of this work was to establish those factors either physical (power input) or chemical (limiting substrate or dilution rate) that enhance cell aggregation (biofilm or floc formation) and cell physiological state during aerobic continuous cultures of Bacillus licheniformis. Glucose-limited steady-state continuous cultures growing at a dilution rate between 0.64 and 0.87/h and 1,000 rpm (mean specific energy dissipation rate (epsilonT) = 6.5 W/kg), led to the formation of a thin biofilm on the vessel wall characterized by the presence of a high proportion of healthy cells in the broth (after aggregate disruption by sonication) defined as having intact polarized cytoplasmic membranes. An increased epsilonT (from 6.5 W/kg to 38 W/kg) was found to hinder cell aggregation under carbon limitation. The carbon recovery calculated from glucose indicated that additional extracellular polymer was being produced at dilution rates >0.87/h. B. licheniformis growth under nitrogen limitation led to floc formation which increased in size with dilution rate. Counter-intuitively the flocs became more substantial with an increase in epsilonT from 6.5 W/kg to 38 W/kg under nitrogen limitation. Indeed the best culture conditions for enhanced metabolically active cell aggregate formation was under nitrogen limitation at epsilonT = 6.5 W/kg (leading to floc formation), and under carbon limitation at a dilution rate of between 0.64 and 0.87/h, at epsilonT = 6.5 W/kg (leading to vessel wall biofilm formation). This information could be used to optimize culture conditions for improved cell aggregation and hence biomass separation, during thermophilic aerobic bioremediation processes.

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Section: Efficiency Of Carbon Conversion In Glucose-limited Culture Asupporting

confidence: 84%

The use of multi‐parameter flow cytometry to study the impact of limiting substrate, agitation intensity, and dilution rate on cell aggregation during Bacillus licheniformis CCMI 1034 aerobic continuous culture fermentations

Silva

Reis

Kent

et al. 2005

Biotech & Bioengineering

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“…Literature data concerning pure cultures of microorganisms mostly report higher decay rates under thermophilic conditions [11,18,28] although some do not [3,6]. Based on the current results and literature data, we believe that bacterial decay is higher under thermophilic conditions compared to mesophilic conditions, but to what extent remains subject to speculation.…”

Section: Decay Ratesmentioning

confidence: 47%

“…Reported l max values for thermophilic wastewater treatment processes vary between 0.1 and 0.5 h )1 [7,8,12,16,20,21,31]. For pure cultures of microorganisms l max values of 1.0 h )1 have been reported [4] but extremely high growth rates of 3.5 h )1 could be obtained only under typical conditions with incomplete substrate utilization [11,28] or by growth on a complex medium [18]. The intrinsic l max values obtained in this study correspond well with the reported literature data and, given the reproducibility of the results, can be regarded as accurate estimates of the intrinsic l max for the specified substrate and temperatures.…”

Section: Maximum Growth Ratesmentioning

confidence: 97%

Kinetic comparisons of mesophilic and thermophilic aerobic biomass

Vogelaar¹,

Klapwijk

Temmink

et al. 2003

J IND MICROBIOL BIOTECHNOL

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Kinetic parameters describing growth and decay of mesophilic (30 degrees C) and thermophilic (55 degrees C) aerobic biomass were determined in continuous and batch experiments by using oxygen uptake rate measurements. Biomass was cultivated on a single soluble substrate (acetate) in a mineral medium. The intrinsic maximum growth rate ( micro (max)) at 55 degrees C was 0.71+/-0.09 h(-1), which is 1.5 times higher than the micro (max) at 30 degrees C (0.48+/-0.11 h(-1)). The biomass decay rates increased from 0.004 h(-1) at 30 degrees C to 0.017 h(-1) at 55 degrees C. Monod constants were very low for both types of biomass: 9+/-2 mg chemical oxygen demand (COD) l(-1)at 30 degrees C and 3+/-2 mg COD l(-1)at 55 degrees C. Theoretical biomass yields were similar at 30 and 55 degrees C: 0.5 g biomass COD (g acetate COD)(-1). The observed biomass yields decreased under both temperature conditions as a function of the cell residence time. Under thermophilic conditions, this effect was more pronounced due to the higher decay rates, resulting in lower biomass production at 55 degrees C compared to 30 degrees C.

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“…This study also indicated that nutrients were not totally depleted at the end of the cultures. In fact, some studies report quite low consumptions of nutrients by Thermus strains [23,24]. In the literature, the peptone and yeast extract concentrations employed are usually the same as the basal medium used in this work [25][26][27][28].…”

Section: Influence Of Nutrient Concentration On T Thermophilus Hb27 mentioning

confidence: 98%

Assessment of Relevant Factors Influencing Lipolytic Enzyme Production by Thermus thermophilus HB27 in Laboratory‐Scale Bioreactors

et al. 2009

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Nowadays, there is not much information on the large-scale production of thermostable lipolytic enzymes by thermophilic organisms. Therefore, in this study the lipolytic enzyme production by Thermus thermophilus HB27 in laboratoryscale bioreactors was undertaken. In order to determine the most suitable bioreactor, two configurations were investigated: stirred-tank and airlift bioreactor. It was demonstrated that the stirred-tank configuration led to the highest lipolytic extracellular activities, about 2.3-fold higher than those found in the corresponding cultivation in the airlift bioreactor. On the other hand, the influence of several factors such as culture nutrients concentration, aeration, and agitation rate on the production of thermophilic lipolytic enzymes in a 5-L stirred-tank bioreactor was assayed. At reduced nutrients concentration (50 % with respect to the basal medium), a higher product/biomass yield was attained, without any operational problems. From the relationship between mass transfer coefficient (K L a), aeration, and agitation rates it was concluded that there is a lesser dependence on the aeration than the agitation rate. In addition, the mechanical stirring of the bioreactor could tear the membranes that contain the rotund bodies often found in cultures of thermophilic microorganisms, thus increasing the extracellular enzyme production.

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The growth behaviour of Thermus aquaticus in continuous cultivation

Cited by 42 publications

References 18 publications

The use of multi‐parameter flow cytometry to study the impact of limiting substrate, agitation intensity, and dilution rate on cell aggregation during Bacillus licheniformis CCMI 1034 aerobic continuous culture fermentations

The use of multi‐parameter flow cytometry to study the impact of limiting substrate, agitation intensity, and dilution rate on cell aggregation during Bacillus licheniformis CCMI 1034 aerobic continuous culture fermentations

Kinetic comparisons of mesophilic and thermophilic aerobic biomass

Assessment of Relevant Factors Influencing Lipolytic Enzyme Production by Thermus thermophilus HB27 in Laboratory‐Scale Bioreactors

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