Difference between revisions of "Team:HUST-China/Comparison between PSB"

These are the main differential equations of the Synechocystis part of the model. The parameters and variables above will be introduced below.

These functions calculate the growth rate of Synechocystis. The two functions correspond to different concentrations of CO₂ in the solution.andmake the growth rate decline when the concentration of CO₂ in the solution is too high or too low. (David et al. 2015)^[1]. From the same reference we get the relationship between the light intensity and the growth rate. The functionis from another reference(XIONG et al. 2012) ^[2]. The parameter the decline of the growth rate caused by gene editing. This parameter is introduced to make the growth model of wild Synechocystis fit to the growth of edited ones in the reference (Henrike et al. 2010)^[3].

This stands for the CO₂ consumed by each unit of Synechocystis.is used for growth,is used for lactate producing, and is used for sustaining its life.

The O₂ consuming is calculated by because the photosynthesis and respiration in Synechocystis have the same stoichiometric ratio.

This function shows the inhibit of CO₂ to the metabolism of Synechocystis. The lack of carbon source will not only effect the growth rate of the bacteria, but also reduce the produce rate of lactate.

These are the main differential equations about the modeling part of the Rhodopseudomonas palustris (abbreviated as “Rps”). Through these differential equations, we can calculate the concentrations of Rps, carbon dioxide and lactate. The parameters and variables above will be introduced below.This part is similar to that of Synechocystis, because in our experiment, they are both used to provide lactate to Shewanella and have similar genetic modification.

The function calculates the growth rate of Rhodopseudomonas palustris. The function corresponds to different concentrations of CO₂ in the solution. makes the growth rate decline when the concentration of CO₂ in the solution is too high. This is gotten from the reference (David et al. 2015)^[1].

From the same reference we get the relationship between the light intensity and the growth rate. The function

is from another reference (Xiong et al. 2012)^[2]. The parameter the decline of the growth rate caused by gene editing. This parameter is introduced to make the growth model of wild Rhodopseudomonas palustris fit to the growth of edited ones in the reference ( Henrike et al. 2012 )^[3].

This stands for the CO2 consumed by each unit of Rhodopseudomonas palustris. is used for growth, is used for lactate producing, and used for sustaining its life.

This function shows the inhibit of CO₂ to the metabolism of Rhodopseudomonas palustris. The lack of carbon source will not only impact the growth rate of the bacteria, but also reduce the production rate of lactate.

In this function, μ is specific growth rate of biomass.

Because there are two important growth factors in our model: lactate and oxygen content, we need some modifying tasks in this model. Noticing that the concentration of oxygen and lactate are both promoting biomass growth, with the inspiration of monod equation, we take the two factors into consideration so the function changes to:

In this function, c_Lac is concentration of lactate.

After this, we realized that a factor about oxygen competition is needed to add in the function. So we import a parameter to solve this problem, the function is modified to:

Taking the efficiency ratio of aerobic and anaerobic respiration (19:1) into consideration, we calculated two parameters:

The two parameters are used in our electricity production simulation:

The basic function is the famous Nernst equation:

In this function Ox is oxidized type, and Red is reduced type.

The Nernst equation is very clear and easy to use, but we have to add a Shewanella biomass factor to show the macroscopic electricity production. The lactic consuming value is closely related to the concentration of Shewanella. In addition, after the metabolic analysis of lactic in Shewanella, we promoted the function by modifying (or simplifying) the section. As a result, the electricity production function is:

In this function,

The last work in Shewanella modeling is the lactic consuming simulation:

The concentration of lactate dominates largely on electricity production. Similarly, with the inspiration of Monod equation, we notice that the concentration of lactate acid and Shewanella itself is in a positive correlation to lactic consuming rate. So we have summarized the lactic consuming equation: