Detection of microbial growth

abstract: the detection of
microorganisms
is of great significance in both theoretical research and production practice, and the method of growth measurement, microbial counting, physiological index method and commercial rapid microbial detection briefly introduces more than 20 commonly used detection methods using microbial weight, volume, size, physiological metabolites and other indicators, and briefly introduces the principles, application scope and advantages and disadvantages of these methods.
Summary:
microbial cells constantly absorb nutrients under the right external conditions and metabolize them in their own way. If the speed of assification exceeds the alienation effect, the total amount (weight, volume, size) of its protons increases, and the growth of individuals occurs. If this is a balanced growth, i.e. when the cellular parts are increased at an appropriate proportion, reproduction occurs to a certain extent, resulting in an increase in the number of individuals, at which point the original individual has developed into a group. As individuals in the group grow further, this group grows, as measured by their volume, weight, density or concentration. The growth of microorganisms is different from the growth of other organisms, and the individual growth of microorganisms is difficult in scientific research, and usually has no practical significance.
microorganisms win by volume, so the growth of microorganisms usually refers to the amplification of populations. The growth and reproduction of microorganisms is a comprehensive reflection of their interaction with various environmental factors inside and outside. Therefore, growth and reproduction can be used as an important index to study various physiological
notogenics and bio-chemicals
and genetic problems, at the same time, microorganisms in the production practice of various applications or disease-caused, the prevention and treatment of moldy microorganisms are closely related to their growth inhibition. Therefore, it is necessary to introduce the detection method of microbial growth. Since growth means an increase in protonic content, the method of assays are also directly or indirectly based on secondary, while the measurement of reproduction is based on counting. Microbial growth can be measured by its weight, volume, density, concentration, and indicators.
growth measurement method:
1, volume measurement method: also known as mycelium concentration method.
the growth of microorganisms
measured
amount of mycelium contained in a certain volume of cultured liquid. The method is to take a certain amount of culture fluid to be tested (e.g. 10 ml) placed in a scaled centrifuge tube, set a certain centrifugal time (e.g. 5 minutes) and speed (e.g. 5000 rpm), centrifugation, poured out of the night, measured the volume of the upper clear night is v, then the concentration of mycelium is (10-v)/10. Mycelium concentration determination is an important monitoring index of microbial growth in large-scale industrial fermentation production. This method is extensive, simple and fast, but needs to set consistent treatment conditions, otherwise the deviation is very large, because the centrifugal sediment is mixed with some solid nutrients, the result will be a certain deviation.
2, dry re-issue method:
can be determined by centrifugation
or
filtration method. Generally dry weight is 10-20% wet weight. In centrifugation method, a certain volume of culture fluid to be measured is poured into the centrifugal tube, set a certain centrifugal time and speed, centrifugation, and with water centrifugation washing 1-5 times,
drying
. Drying can be done in 1050C or 1000C ovens, or in infrared drying, or in 800C or 400C vacuum drying, after drying weighing. Such as the use of filtration method, silk
fill
can be filtered with filter paper, bacteria can be filtered with acetic acid fiber membrane and other membranes, after filtration with a small amount of water washing, under 400C vacuum drying. Weighing and re-eding is cumbersome, and is often used when obtaining microbial products as bacterials, such as active dry
yeast
(activity dry yeast, ADY), some feed and fertilizers with microbial bacteria as active substances.
3, than turbidity method:
microorganisms caused by the growth of culture turbidity increased. The absorption value at a certain wavelength is determined by the ultraviolet terrolight meter to determine the growth of microorganisms. A special triangular flanter with side arms may be used to keep a timed track of the growth of bacteria in a culture. By inserting the side arm into the color base hole of the photoelectromeometer, its growth can be determined at any time without the need for fungicides. This method is mainly used for the monitoring of the growth of fermented industrial fungi. As I use UNICO's UV-visible tradiscometer, the absorbance value of the fermentation fluid OD600 is timed at a wavelength of 600nm to monitor the growth and induction time of E.Coli.
4, mycelium length measurement method:
for silky fungi and some line-releasing bacteria, you can determine the length of mycelium growth over a certain period of time on the
-culture base
, or the use of one end of the opening and with a scale of fine glass tube, into a suitable culture base, lying, inoculated at one end of the opening microorganisms, after a period of time to record the growth of the silk microorganisms.