Continuous culture of micro-organisms

The continuous growth of micro-organisms, as with continuous chemical reactions, may be carried out either in tubular fermenters (plug flow) or in well-mixed 

If a CSTF is considered (Fig. 5.56), which has a volume V, volumetric feed flow rate F, with influent substrate and biomass concentrations S0 and X0 respectively, then suppose that the substrate and biomass concentrations in the fermenter are 5 and X. A material balance can be established over the fermenter in the same manner as for the batch fermenter. This is  

Flow of material + Formation by biochemical Flow of material = Accumulation 

The balance may be carried out for both biomass and substrate, noting that the formation term for the substrate becomes negative since biomass is formed by the consumption of substrate. For the biomass this becomes  

3ts being the corresponding rate of formation of substrate (negative). 

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HHW] S. B. Hsu, S. P. Hubbell, and P. Waltman (1977), A mathematical theory for single nutrient competition in continuous cultures of micro-organisms, SIAM Journal on Applied Mathematics 32 366-83. 

HERBERT, D. (1961). Continuous Culture of Micro-organisms, SCI Monograph No. 12, Society of Chemical Industry, London, p. 21. 

Ramkrishna et al.m proposed a similar model at about the same time—this too was an unsegregated model which also divided the biomass into two compartments. They referred to the material in the two compartments as G-mass and D-mass, respectively, and suggested that these materials were formed in parallel. They also proposed that the micro-organism produced a toxic substance which inhibited its growth. They produced a set of differential equations obtained from material-balance considerations, to describe the behaviour of such a system in both batch and continuous culture. For batch culture ... 

The rotifers are fed microalgae, yeast cells or commercial products, based on one or both of the previous micro-organisms, according to the number of rotifers. The feed can be administered manually or through automated devices (e.g. peristaltic pumps). The rotifer growth rate can be around 1.5/day (Kostopoulou and Vadstein, 2007). As the culture period continues, the water quality decreases. This has a negative impact on the... 

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