Kinetics of microbial growth with mixtures of carbon sources

Egli, Thomas; Lendenmann, Urs; Snozzi, Mario

doi:10.1007/bf00871224

Cited by 103 publications

(94 citation statements)

References 27 publications

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“…(b) Bulk C:N may not be representative of the substrates actually available and taken up by bacteria (112). (c) Nutrients and organic carbon may colimit BGE (39,40).…”

Section: Nutrient Limitation Of Bgementioning

confidence: 99%

“…Second, the appearance of nutrients and carbon sources for bacterial growth is transient, and the ability to respond to sudden increases in nutrient levels is an essential property for survival in dilute environments. It is also clear that bacteria under carbon limitation are able to simultaneously take up and catabolize a wide variety of substrates (39,40), but there is a cost in maintaining the transport proteins, catabolic enzymes, and functional membrane systems needed to deal with both the variety and low concentrations of substrates (31,96). The energetic cost of maintaining such a wide array of highly efficient transport systems has never been explicitly assessed in natural bacteria.…”

Section: Transport Of Nutrientsmentioning

confidence: 99%

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Bacterial Growth Efficiency in Natural Aquatic Systems

Giorgio

Cole

1998

Annu. Rev. Ecol. Syst.

1,187

904

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Heterotrophic bacteria perform two major functions in the transformation of organic matter: They produce new bacterial biomass (bacterial secondary production [BP]), and they respire organic C to inorganic C (bacterial respiration [BR]). For planktonic bacteria, a great deal has been learned about BP and its regulation during the past several decades but far less has been learned about BR. Our lack of knowledge about BR limits our ability to understand the role of bacteria in the carbon cycle of aquatic ecosystems. Bacterial growth efficiency (BGE) is the amount of new bacterial biomass produced per unit of organic C substrate assimilated and is a way to relate BP and BR: BGE = (BP)/(BP + BR). Estimates of BGE for natural planktonic bacteria range from <0.05 to as high as 0.6, but little is known about what might regulate this enormous range. In this paper we review the physiological and ecological bases of the regulation of BGE. Further, we assemble the literature of the past 30 years for which both BP and BR were measured in natural planktonic ecosystems and explore the relationship between BGE and BP. Although the relationship is variable, BGE varies systematically with BP and the trophic richness of the ecosystem. In the most dilute, oligotrophic systems, BGE is as low as 0.01; in the most eutrophic systems, it plateaus near 0.5. Planktonic bacteria appear to maximize carbon utilization rather than BGE. A consequence of this strategy is that maintenance energy costs (and therefore maintenance respiration) seems to be highest in oligotrophic systems. 503

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“…(b) Bulk C:N may not be representative of the substrates actually available and taken up by bacteria (112). (c) Nutrients and organic carbon may colimit BGE (39,40).…”

Section: Nutrient Limitation Of Bgementioning

confidence: 99%

Section: Transport Of Nutrientsmentioning

confidence: 99%

Bacterial Growth Efficiency in Natural Aquatic Systems

Giorgio

Cole

1998

Annu. Rev. Ecol. Syst.

1,187

904

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“…However, it has been shown recently that E. coli cells are able to utilize mixtures of sugars simultaneously when cultivated in carbon-limited continuous culture (10). Therefore, steady-state sugar concentrations were measured as a function of temperature in cultures growing with a 1:1 mixture of glucose and galactose.…”

Section: Vol 178 1996 Temperature-dependent Growth Kinetics Of E Cmentioning

confidence: 99%

“…As discussed above, the former phenomenon is based on the kinetic properties of a particular strain. However, the efficiency with which a bacterium takes up substrate is influenced by a variety of environmental factors, an important one being the presence and simultaneous utilization of additional substrates (10). Therefore, one would expect that the concentrations of particular substrates under environmental conditions should be lower than those observed for laboratory-scale experiments in which these compounds are supplied as the only substrates for growth.…”

mentioning

confidence: 99%

Temperature-dependent growth kinetics of Escherichia coli ML 30 in glucose-limited continuous culture

1996

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Knowledge concerning the influence of environmental factors such as temperature, pH, salinity, etc., on microbial growth is of crucial practical importance in the control of bioprocesses, for the safe handling of food (1, 2, 12, 50, 51), in wastewater treatment (7), and in bioremediation (2). In addition, in taxonomy, cardinal temperatures for growth are key characteristics of microbial strains (37).In recent years, several models for predicting the growth rate of microorganisms as a function of either temperature alone (11,13,22,31,32,52,53) or of temperature in combination with other factors have been proposed (1, 5, 20-22, 36, 50). Surprisingly, few attempts at a better basic understanding have been made to relate the rate of growth and actual substrate concentration. This relationship is traditionally termed growth kinetics (23,30). (However, note that the same expression has also been used for the description of the time courses of population densities [5].) The current lack of systematic data on the influence of temperature on the kinetics of growth makes the prediction of this effect difficult. Temperature modulation of growth kinetics is to be expected, because both metabolism and cellular composition are affected by cultivation temperature, as was demonstrated by the cellular fatty acid composition (16, 26, 41), the synthesis or degradation of certain proteins (14,15,17,20,25), changes in protein activity (15, 35), changes in maintenance requirements of cells (19,27,39,42,47), changes in end products of metabolism (17), and increases in pigment formation (27).Bacterial metabolism represents a network of reactions. Although these individual biochemical reactions are temperature dependent, the fundamental question of whether the parameters used in growth kinetic models are temperature dependent must be asked. To determine this, a detailed comparison of growth kinetics at temperatures below and above the optimal temperature was carried out for Escherichia coli ML 30 cultivated in continuous culture with glucose and/or galactose. Such investigations are possible only by using an extremely sensitive method for measuring low concentrations of sugars (in micrograms per liter) in culture media (40). The objective of the present study was to compare the experimentally established relationships between growth rate and steady-state substrate concentrations at different constant temperatures and to find out whether the whole set of relationships can be described by a simple mathematical model (Table 1 summarizes the nomenclature used throughout). Additionally, the effect of temperature on steady-state substrate concentrations at constant growth rates (dilution rates in continuous culture) was studied.Compendium of the models proposed in the literature. (i) Conventional growth kinetics and models containing an s min term. Various mathematical models have been proposed to quantitatively describe microbial growth kinetics. The Monod model (equation 1) is considered the basic equation (23), which has since been improve...

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“…Initially, only the substrate that supports the highest growth rate is utilized by the alga, while the consumption of other substrates remains repressed. Only after the preferred substrate is totally consumed the microalga begins metabolizing the other carbon sources [59]. For this reason, a high acetate concentration can ensure that enough cells will initially be produced in order to consume the other "poorer" substrates afterwards.…”

Section: Mixture Of Vfa As Carbon Sourcementioning

confidence: 99%

Utilization of Volatile Fatty Acids from Microalgae for the Production of High Added Value Compounds

et al. 2017

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Volatile Fatty Acids (VFA) are small organic compounds that have attracted much attention lately, due to their use as a carbon source for microorganisms involved in the production of bioactive compounds, biodegradable materials and energy. Low cost production of VFA from different types of waste streams can occur via dark fermentation, offering a promising approach for the production of biofuels and biochemicals with simultaneous reduction of waste volume. VFA can be subsequently utilized in fermentation processes and efficiently transformed into bioactive compounds that can be used in the food and nutraceutical industry for the development of functional foods with scientifically sustained claims. Microalgae are oleaginous microorganisms that are able to grow in heterotrophic cultures supported by VFA as a carbon source and accumulate high amounts of valuable products, such as omega-3 fatty acids and exopolysaccharides. This article reviews the different types of waste streams in concert with their potential to produce VFA, the possible factors that affect the VFA production process and the utilization of the resulting VFA in microalgae fermentation processes. The biology of VFA utilization, the potential products and the downstream processes are discussed in detail.

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Kinetics of microbial growth with mixtures of carbon sources

Cited by 103 publications

References 27 publications

Bacterial Growth Efficiency in Natural Aquatic Systems

Bacterial Growth Efficiency in Natural Aquatic Systems

Temperature-dependent growth kinetics of Escherichia coli ML 30 in glucose-limited continuous culture

Utilization of Volatile Fatty Acids from Microalgae for the Production of High Added Value Compounds

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