Yield Coefficient

In the field of Dairy Microbiology, the term yield coefficient plays an important role in the identification of the Substrate to biomass yield for commercial purposes of dairy items. The quantitative study of the “Cell growth rate (dX/dt)” in comparison with the “Consumption of Substrate dS/dt” is known as the Yield coefficient. In terms of cell growth rate, the formula stands as {substrate of biomass yield (dXS) = cell growth rate (dX/dt) / Consumption of substrate (dS/dt)}.  It can also determine the quantitative study of Biomass production by the use of equal amounts of substrate. The formula for Yield coefficient is:

{Biomass Yield (Y)= Biomass produced (g)/ Substrate utilized (g)}

Discussion

The definition of Yield Coefficient can be sourced as the ratio of the Mass of Microorganisms to the mass of Substrate used in the production. It can be better explained with the example of the Aerobic catabolism of glucose molecules. It has been observed that the growth yield per available electron of oxygen ranges from 3.14 to 0.11gdw. This signifies that in the chemical reduction process of glucose molecules, oxygen plays the part of the substrate in the process of getting the biomass product. The process is generally involved with fermentation or organic materials of which dairy is an important aspect. According to the growth yield coefficient, the mass of the cell and the product formation of the microorganisms collectively comprise the Biomass. The unit production of biomass over the unit consumption of substrate is known as the Yield coefficient. 

The concept of Yield coefficient of biomass, deals with the calculation of the quantity of biomass produced with the quantity of substrate consumed for its production. It is defined based on the type of electron donor used in the reduction process. The quantitative study is based on the coefficient of linear regression of the biomass concentration in a product against the substrate concentration in the same product. The example of the organic substrate can be related to Glucose, glycerol, arabinose and other sources of carbon. The unit of quantity identification is mentioned to be grams of biomass/ nmolC. 

The yield coefficient is commonly known as the substrate to biomass ratio to calculate the rate of cell growth of a microorganism within a product and also the calculation of the mass of the product with the increase in the cell growth. There is also a decrease in the substrate of the product as the microorganism feeds on the substrate in order to increase the organism production and the biomass growth of the organic product. The differential equation of dX/dt in relation with dS/dt, explains the rate of decrease of the substrate of a product in variance with the rate of increase of biomass within the same product.

The characteristics of the Yield coefficient can be described as follows:

• A static increase in the cultured dry weight is a reliable measure on the part of the researcher to increase the hyphal length of the product.
• It is calculated that the culture of absorbance is a non-destructive process to determine the increase in the weight of the bioproduct.
• A general increase in the culture absorbance is a reliable aspect in the static increase of the total quantity of the hyphal tips in the culture.

On plotting the data of the total hyphal length of increase with time it has been observed that the curve is static till the 50th unit in the log scale but post this condition the hyphal length shows abnormal movement with the increase in the time axis. The abnormality of the movement is directed towards the non static curve of the yield coefficient which loses its balance with the time axis once the hyphal length moves beyond the effective standard. This inversely affects the weight of the biomass in relation to the quantity of the substrate used for the reduction process.

In order to define the Yield coefficient in the bioprocess, it can be said that consumption of the oxygen molecule per mole of the substrate used is termed as the bioprocess yield coefficient. The use of the Yield coefficient is essential to the daily products used by humans. It is basically known as Stoichiometry that helps in the production of soap, deodorant, types, and gasoline. Apart from chemical products, it has its use in the production of Organic products as well as the study of Microbiology. 

The Yield coefficient of biomass refers to the use of a stoichiometric coefficient that focuses on the growth rate efficiency of a specific microbial strain. It also helps indicate on the quantitative aspect the biomass is grown and product formation by the consumption of every unit of the substrate. The yield (X) can be calculated by the process of subtraction of the initial biomass (X0) from the final biomass (Xmax) of the product. The yield coefficient (Y) is formed by the ratio of the actual yield extracted as (X) and the amount of substrate consumed throughout the project (S). It can be equated as (Y= X/S). In the case of organic substances, the process is known as Fermentation and the microbe is known as Yeast, which acts upon the substrate containing glucose in order to form the Biomass. Although the calculation of the coefficient (Y) is subject to variance with the variety of microorganisms used ranging from bacteria to yeasts is generally non-destructive in nature and affects most of the growth experiments providing closely responsive results. The difference between the biomass and the yield depends highly on a given area at a specific moment of the culture. 

Conclusion

The calculation of the coefficient of biomass is a quantitative measure of the biomass increased after the consumption of the substrate throughout the reduction process. Microbes are an essential part of the reaction. The process of Biochemistry is used in multiple aspects to determine the chemical and organic reactions needed for the production of multiple products needed by humans.