Nitrifying bacteria - online biological toxicity warning

In recent years, nitrifying bacteria have gradually become a hot topic in the aquaculture industry, and its importance in aquaculture has begun to attract widespread attention. It can be said that, in the large-scale, intensive aquaculture model, it is quite difficult to obtain successful culture without the involvement of nitrifying bacteria in the purification of water.

Fish, shrimp and other aquatic animals eat, drink, excrete, live and rest are carried out in the water. Then, how to manage the water quality of the water body to suit its growth, survival and robustness has become an important issue. In particular, modern intensive farming has accumulated a large amount of cultured biological excreta for a long time. All organic excreta and even its corpses, under the action of heterotrophic bacteria, will slowly decompose proteins and nucleic acids, causing a large amount of ammonia and other nitrogen-containing harmful substances. substance. Ammonia is converted into nitrous acid under the action of nitrosating bacteria or photosynthetic bacteria. Nitrous acid can form nitrite after combining with some metal ions, and nitrite can combine with amines to form nitrosamine with strong carcinogenic effect. . Therefore, nitrite is often compared with the infamous ammonia. Because of the long-term accumulation of nitrite poisoning, the disease resistance of fish and shrimp is reduced, which is easy to invade various pathogens, so it is often regarded as the cause of fish and shrimp. The root cause of the disease. However, when nitrous acid is converted to nitric acid by nitrification of nitrifying bacteria, nitrate is easily formed, thereby becoming a nutrient that can be absorbed and utilized by plants. Therefore, the relationship between nitrifying bacteria and the breeding environment is very close.

Some heterotrophic bacteria and fungi that claim to have nitrification on the market, although they can also oxidize ammonia into nitrates, usually can only use organic carbon sources to obtain energy, can not use inorganic carbon sources, and its oxidation of ammonia is very weak. The reaction rate is much slower than that of autotrophic nitrifying bacteria and cannot be considered as true nitrification.

Nitrification must be done by autotrophic nitrifying bacteria. The culture pond is rich in nitrogen source, which is very suitable for the growth of nitrifying bacteria. However, due to the large number of heterotrophic bacteria in the culture pond, it is rejected by heterotrophic bacteria. It is suitable for nitrifying bacteria to inhabit. The relative natural environment is obviously less. More, so there is not enough autotrophic nitrifying bacteria to consume excess nitrite, which is the problem.

First, the basic concept of nitrifying bacteria

Nitrifying bacteria are a type of bacteria that uses ammonia or nitrite as the main source of energy and carbon dioxide as the main carbon source. Nitrifying bacteria are one of the oldest bacteria. They are widely distributed in soil, fresh water, seawater and sewage treatment systems, but rarely appear in nature. The reason is that the distribution of nitrifying bacteria is affected by many environmental factors, such as nitrogen sources. Temperature, oxygen concentration, osmotic pressure, pH and salinity, etc.

Nitrifying bacteria are divided into nitrosating bacteria and nitrifying bacteria. The main function of nitrosating bacteria is to convert ammonia nitrogen into nitrite; the main function of nitrifying bacteria is to convert nitrite into nitrate. Both ammonia nitrogen and nitrite are toxic substances produced during aquaculture, and nitrite is also a strong cancer-causing substance. Therefore, how to degrade these two substances is the focus of scientific work in recent years, due to the nitrosation bacteria. The growth rate is relatively fast and photosynthetic bacteria also have the effect of degrading ammonia nitrogen, so modern farming has been able to successfully control ammonia nitrogen at a lower level. For nitrite, nitrite produced in the breeding process has become a key factor hindering the development of aquaculture because the growth of nitrifying bacteria in nature is extremely slow and no other microorganisms have been found to replace the function of nitrifying bacteria. After years of hard work, the researchers have successfully developed a new type of purified nitrifying bacteria preparation “Nitrification Bao”, which can effectively reduce the nitrite to the specified concentration.

Second, the biological characteristics of nitrifying bacteria preparations

In order to grow and multiply, in addition to the basic materials that can be used to construct cellular components, organisms must also obtain energy. Nitrifying bacteria are a kind of autotrophic bacteria that use inorganic materials to obtain energy. Nitrifying bacteria use nitrite nitrogen to obtain the chemical energy required for the synthesis reaction, and manufacture sugars in the body. It takes a long time to manufacture sugars. Unlike other heterotrophic bacteria, which can directly decompose and take up the sugars needed from organic matter, the growth rate of nitrifying bacteria is much slower than that of general heterotrophic bacteria. Under natural conditions, the effects of nitrification and denitrification cannot meet normal culture. Need. Temperature, pH and dissolved oxygen concentration in water have an important influence on the growth of nitrifying bacteria.

Nitrifying bacteria are the main microorganisms in the biological nitrogen removal process. The amount of nitrifying bacteria in water directly affects the nitrification effect and the biological nitrogen removal efficiency. The concentration of nitrifying bacteria preparation is proportional to the nitrification efficiency.

If there is no nitrifying bacteria in the aquarium, it will inevitably face the danger of a surge in ammonia content. No matter which method or any aquarium supplies you use, this problem cannot be completely solved. When the ammonia concentration in the water reaches the lethal concentration of the aquarium, the result may be the same for any kind of aquarium - that is death, then you will be guilty. However, if the water contains a sufficient amount of nitrifying bacteria to continuously remove ammonia from the water, the stability of the entire aquarium ecological balance system will be ensured, and the aquarium organism will live safely in the aquarium.

The German Lal ToxAlarm online warning system is used to measure oxygen consumption. Toxic substances in the sample can inhibit bacterial respiration and reduce oxygen consumption. Therefore, the consumption of oxygen by nitrifying bacteria allows us to draw conclusions about the toxicity of the sample.

Nitrifying bacteria are aerobic bacteria that can grow in oxygenated water or gravel and play an important role in the purification of nitrogen cycle water. They include a bacterium of the morphologically different type, a bacterium of the bacterium, a bacterium of the bacterium, and a bacterium of the genus, which belong to a class of absolutely self-supporting microorganisms, including two completely different metabolic groups:

1. genus nitrite (Nitrosomonas): elimination of bacteria (by oxidation) and generates ammonia Eco nitrite in water in the system; nitrous acid bacterium, generally known as "ammonia by oxidation" because The source of food that is produced is ammonia, and the chemical energy generated by ammonia and oxidation is sufficient to survive.

2. genus nitrate (Nitrobacter): nitrous acid molecule may be further oxidized into nitric acid bacteria molecules. Nitrobacter bacteria, commonly referred to as "oxidizers of nitrous acid", because the food source they produce is nitrous acid (but not necessarily nitrous acid, other organic substances are also possible), it can be produced by oxidation Nitric acid produces enough chemical energy to survive.

Because these nitrifying bacteria can decompose and remove toxic chemicals (ammonia and nitrous acid) in the water, they have the function of purifying water. But note: nitrifying bacteria works best at neutral pH water quality, weak alkaline environment, an effect of the worst quality in the acid.

This article was published by Yingnuo Instruments (Shanghai) Co., Ltd.