When we cultured in bacteria by adding growth promoting factors for rapid growth, what happened in this time. At that time bacteria growth/size are increase or both. Please any one can explain in details. I only confirm one thing---When we use growth promoting factors/compounds in culture media for vigorous growth of bacteria, specifically that time what happened? speed the growth and size of bacteria both or only size or only speed. Actually this is my question.
In general, yes there is a relationship between inoculum size and growth rate of the culture, it was found that there is an inverse relationship between the inoculum size and the culture growth rate.
You can actually reduce the generation time by increasing growth factors. In some cases second round of DNA replication starts even before the cell division. As it's mentioned already as the cell number increases growth rate decreases due to formation of primary and secondary metabolites during the course of fermentation.
Hi there,
I guess you are talking about the size of the bacterial cell. Size of the cell is a determinant for trigger ing cell division. So within a culture the cell size varies from the size of newborn cell to the dividing cell. Whatever the growth rate, during exponential phase the average size of the cell will be the same. The other main parameters which influence growth rate are nutrient availability and density of cells.
You may increase bacterial inoculant size to reduce incubation time to reach the max population size. However, the exponential culture, the normally harvested growth stage for experiment, you will be getting is occupied with less fresh cells than if you were using smaller inoculant size (recommended inoculant size is 1%).
Thank you everybody for nice explanation. I only confirm one thing---When we use growth promoting factors/compounds in culture media for vigorous growth of bacteria, specifically that time what happened? speed the growth and size of bacteria both or only size or only speed. Actually this is my question.
Yes there is a relationship between the bacterial population and growth. Generally, the inoculum size of bacteria determine a significant role in the bacterial growth. If you add growth promotor, and the condition of the growth are well, and the inoculum size of bacteria is high, it will be a high competition between the bacteria cells in the culture and this will be not good for your result. I suggest first you control the bacterial inoculum size.
Hola:
Si añades factores de crecimiento a tu cultivo favoreces la velocidad de duplicacion celular y por supuesto el tamaño de las mismas, ya que para que esto ocurra debe madurar según su ciclo de vida. Ahora debes tener en cuenta el tamaño del inóculo y la formación de componentes celulares dependientes de nutrientes como ciertos polisacáridos de la pared celular. El aumento de la talla celular también puede ser indicios de envejecimiento y lisis celular por deficit de nutrientes al acelerar el metabolismo de las mismas.
Dear Dr. Nadia,
I translated your spanish to english through internet. Please check it.
If growth factors add to your culture you favor the rate of cell duplication and of course the size of them , and that for this to happen should mature as their life cycle . Now keep in mind the size of the inoculum and dependent formation of nutrients such as certain cell wall polysaccharides cellular components. The increased cell size can also be signs of aging and cell lysis deficit nutrients to accelerate the metabolism of the cell.
I sense some confusions between the specific growth rate (K/hour - some call it u/hour) and the final cell yield (the final OD600 of the final cell mass in the culture. The specific growth rate (K.hr-1) specifies the rate of growth in the exponential phase. K.hr-1 is the fractional increase of the population at a given time (think of as the compounded interest rate you receive from the bank for the money you have in a saving account). K.h-1 has an inverse relationship to the generation time (g. min or hour) [i.e., the faster the growth rate the shorter the generation time]. The generation time is is defined as the time for one cell becomes two. The generation time (g) equals Ln 2/K.h-1 or 0.693 divided by the specific growth rate.
Now the final cell yield (Y) is equal to the dry weight of the cells/ml or liter at the end of growth (Stationary Phase) minus the dry weight of the cells/ml at time zero.
Adding nutrients or growth factors could increase K.h-1 only or Y only or both. Therefore, it is important to do a growth curves and measure the sp. growth rate K/hr (during Logarithmic growth phase) and wait till the increase in Optical density stop and measure the final cell yield. This way you can conclude if your added nutrient affected K.h-1, g.time, or both.
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