A healthy aquatic environment involves a complex web of interactions between a variety of factors including organic input (BOD, COD), dissolved oxygen, pH, alkalinity, toxins, temperature, mixing, nutrients (nitrogen, phosphorus), microbial activity and other components. In a pristine aquatic environment, the organic inputs from animals, plants, soil and the atmosphere are relatively stable, and the other factors are “balanced” in relation to this input. However, in contained facilities (aquaria, fish and shrimp rearing facilities) the quantity and concentration of the organic input from undigested feed and feces is greatly increased. This changes the stability of the system, sending “ripples of stress” through the aquatic web, effecting the health of the fish or shrimp. Although it is beyond the scope of this document to address all the factors involved in a pond environment, this document will address the rational for the use of TipTopp Aquaculture’s products to reduce ammonia, sludge build-up, and pathogens.
While the terminology maybe confusing, the main point of this document is that the Bacillus spp. in TipTopp Aquaculture’s products improve the aquatic environment by the following methods: reduce the available nitrogen compounds by two processes (Denitrification and Assimilation); reduce sludge production due to the production of extracellular enzymes; and reduce pathogens by producing a variety of “special compounds” (that fall into other classifications such as antibacterial and antifungal compounds.
Nitrification
Nitrification is strictly an aerobic process and is carried out by two groups of bacteria Nitrosomonas sp. and Nitrobacter sp. To be certain this process occurs in most fresh waters and well aerated soils. However, it is also certain that this process is extremely sensitive to a variety of factors and the growth of these bacteria is very slow (doubling time 6-12 days). These sensitivities include: BOD around 20 mg/L; Temperature (optimum range 26-300 C), Dissolved Oxygen (1.5 – 3.0 mg/L); pH , 7.2-8.4 (stops at 6.0); Alkalinity (7.2 mg Alkalinity consumed, as CaCOd1.0 mg NH4-N oxidized); and sensitivity to a variety of toxic chemicals. This is further complicated by interactions, for example the nitrification process uses alkalinity and, in the process, drops the pH. If adequate alkalinity is not available, the process will stop itself. Thus, any significant change in any one of these factors can cause an upset and stop the process and will take a long time to recover. Thus,
Nitrosomonas sp. and Nitrobacter sp. are very slow growing, difficult to enumerate, and are very sensitive to a variety of factors.
Relevance to Products: This means Nitrosomonas sp. and Nitrobacter sp. are unlikely to survive in a dry form, have a poor shelf-life, require long lead-times, and have low or non-existent microbial concentration. While there are products that contain Nitrosomonas sp. and Nitrobacter sp. they tend to be liquid, require refrigeration, have a short shelf-life, and are very expensive.
Denitrification
Denitrification or more properly called Dissimilative Nitrate Reduction, converts nitrate to nitrogen gas, is strictly an anaerobic process, and is conducted by facultative anaerobic bacteria such as some Bacillus spp. In this case, nitrate is used as an alternative energy source, when oxygen is unavailable, to conduct the cells activities. In most cases, the end product of this process is nitrogen gas, which is transferred to the atmosphere. Frequently, this phenomenon is observed in calm lakes and in the secondary clarifier of wastewater treatment plants by the presence of bubbles rising to the surface.
Relevance to Products: TipTopp Aquaculture’s products contain
Bacillus strains that are facultative anaerobic bacteria, that is they reduce the nitrate by producing nitrogen gas, which is transferred from the pond to the atmosphere, removing it from the aquatic system.
Assimilation is the incorporation of nitrogen compounds into the cells. These compounds can be either ammonia or nitrate and are converted to amino acids then protein by the growing cells.
Relevance to Products: Unlike many non-sporulating bacteria, the Bacillus spp. in TipTopp Aquaculture’s products are spore formers. That is when conditions are unfavorable, they will form a “resting cell.” Thus, instead of dying, decomposing and releasing the nitrogen back into the system, they “sequester” the nitrogen or “hold-on-to-it” until they are able to continue growing.
Nitrogen concentration
Organic Input: Obvious to growers is the additional waste generated by the growing fish or shrimp and the deleterious effects that it has on the health of the fish. This increased organic input is the trigger that creates a cascade of problems for the growing animals. In addition to changes in the nitrogen concentration, this will increase sludge depth (reducing the effective volume of the pond and will increase disposal costs), and this will create additional stress on the fish, often leading to infections.
The “forte” of the Bacillus spp. is the production of extracellular substances. These include a variety of extracellular enzymes (amylases, proteases, lipase, urease, cattiness, etc.) and anti-microbial products. The extra-cellular enzymes play a vital role in breaking down the polymers in the organic material, thus, degrading the organic input and reducing the sludge accumulated in the pond. Essentially, these enzymes conduct the first, often rate limited step, in the degradation of polymers. This activity produces smaller molecules that can be absorbed and transported into the cells for growth.
Anti-microbial compounds
The anti-microbial compounds are often referred to as “special compounds, secondary metabolites or “special metabolites.” These compounds are believed to improve the survival capability of the cells. These processes includes various mechanisms of action: production of antimicrobial substances, changes in the micro-environment, and competition for substrates. The compounds may include complex molecules like antibiotics, hydrolytic enzymes, production of phages; biosurfactants; and less complex molecules, like organic acids.
Relevance to Products: This means that the Bacillus spp. in TipTopp Aquaculture’s products will degrade the incoming organic material faster, produce less sludge, reduce the sludge in the pond (reducing the frequency of pump-outs), and reduced the frequency of infection.
Summary: The Bacillus spp. in TipTopp Aquaculture’s products improve the aquatic environment by the following methods: reducing the available nitrogen compounds by Denitrification and Assimilation; degrading the incoming organic material faster; reducing sludge production due to the production of extracellular enzymes; and reducing pathogens by producing a variety of “special compounds.” In contrast, the claim of reducing nitrogen by the inclusion of nitrifiers in their products, especially dry products, is unlikely because of problems with stability, growth rates, numbers, and the inherent sensitivity to environmental conditions and toxic compounds.
