Limitation bacterial growth rate

Values of q >1 thus correspond to steady states with carbon-limited bacterial growth rate, whereas values of q <1 correspond to mineral nutrient limitation. Equation (3) illustrates how everything depends on everything in a steady-state situation. The value of q is a function not only of the ratio between production rate of organic bacterial substrates and the product of loss rates of the bacterial predators and competitors to higher predators, but also of all the parameters representing physiological properties of bacteria, bacterial competitors, and bacterial predators. 

The formula for BCD in Eq. (2) was derived under the assumption that the bacterial growth rate was mineral nutrient limited. If the supply rate of labile organic carbon from allochthonous and autochthonous sources is insufficient to meet this demand, the pool of labile dissolved organic carbon (DOC) will eventually be depleted and the bacteria will become carbon... 

The poor correlation between bacterial growth rate and droplet size is due partly to the limitations of the light microscope method used (Dolby, 1965). Other influencing factors are nutrient level, salt and pH of the droplet... 

The relationship between nutrients and the growth of populations of microorganism can be described in three ways. The simplest theory is the one developed for organic-carbon-limited bacterial growth by Monod (1942) and popularised for application to phytoplankton by Dugdale (1967). In this MONOD theory, the rate of uptake of dissolved nutrient (per unit biomass) depends on ambient concentration S ... 

Elser, J. J., L. B. Stabler, and R. P. Hassett. 1995. Nutrient limitation of bacterial growth and rates of bacterivory in lakes and oceans A comparative study. Aquatic Microbial Ecology 9 105-110. 

On the contrary, lysis and particularly viral lysis could be a major process in these bioassays. In cultures of natural marine bacteria inoculated into 0.2 pm filtered sea water, Wilcox and Furhman (1994) reported that virus abundance increased after few days of bacterial growth. The high abundance and production of bacteria in the HFe bioassay could enhance viral activity and consequently increase specific mortality rates. In agreement with this, during the mesoscale Fe fertilization EISENEX, a higher viral infection of bacterioplankton was estimated in the Fe-enriched patch (Weinbauer et al. 2003). Lysis could be of significance in Fe-limited ecosystems, as Fe released via lysis can be highly bioavailable (Poorvin et al. 2004). 

Water activity has a profound effect on the rate of many chemical reactions in foods and on the rate of microbial growth (Labuza 1980). This information is summarized in Table 1-9. Enzyme activity is virtually nonexistent in the monolayer water (aw between 0 and 0.2). Not surprisingly, growth of microorganisms at this level of aw is also virtually zero. Molds and yeasts start to grow at aw between 0.7 and 0.8, the upper limit of capillary water. Bacterial growth takes place when aw reaches 0.8, the limit of loosely... 

Iron interactions with N sources are not limited to phytoplankton. Kirchman et al. (2003) found that the growth rate, respiratory electron transport system activity, and growth efficiency of a marine gamma proteobacterium (Vibrio hatveyi) were much lower in Fe-limited cultures grown with NOs" than when NH4+ or amino acids were suppHed as N sources. They suggested that these results may help to explain why natural bacterial communities in nitrate-rich, iron-poor HNLC areas also typically exhibit reduced growth rates and efficiencies. 

This means that, under conditions of catabolite limitation, Eqn. 70 will give the most easily interpretable relation. Conversely, under anabolite limitation, Eqn. 71 will be the most practical. Both equations predict a linear relation between rate of substrate utilization and biomass formation. Furthermore, the relation between catabolism and anabolism has a positive intersection point with the ordinate. This positive catabolism at (extrapolated) zero growth rate has been interpreted as maintenance energy requirement [52]. It follows naturally from the simple description of bacterial metabolism as we have used it here. 

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