"Pepsick Tank-Cleaner" can efficiently kill bacteria, viruses, fungi, and other microorganisms that affect the health of fish in the water, ensuring good water quality and healthy survival of fish. According to our experiment results, it has a strong effect and can maintain the product for about a week. Users only need to soak a bag of particles to sterilize the fish tank, which is very convenient and fast.

"Pepsick tank cleaner" is a soluble powder. Each 100 gram of medicine is put into a sealed plastic composite film bag independently. There are 20 bags in each box. The powder consists of tiny particles of white color, which dissolve in water in 10s. The ability of rapid dissolution can prevent fish from eating undissolved particles. Because the antibacterial peptide is a protein, fish can digest it without side effects. Humans can also digest this protein. Therefore, our products are not harmful to fish and human beings.

Pepsick's final product, "pepsin tank cleaner", is stored in a sealed plastic composite film bag, ensuring tightness and avoiding risk during transportation. Antibacterial peptides will dissolve in water and selectively destroy harmful microorganisms to ensure the safety and cleanness of water. Our products can disinfect, purify water, decompose waste, increase the survival rate of aquarium fish, remove fishiness, and multiscene application. There are 20 independent bags in each box, which customers can use for a long time without frequent purchases.

To confirm the function of the AMPs to inhibit bacterial growth, we used the real mixed bacteria acquired from Haichang Ocean Park as bacteria, and antibiotics as a positive control for bacteriostatic test experiments. To better show the relationship between the concentration of AMPs and the inhibition of bacterial growth, we added 100 μL of mixed bacteria and 100 μL of different concentrations of the AMPs to each tube and repeated them three times for each concentration to form the average data graph with error bars.
The experimental results showed that the five AMPs proteins had significant antibacterial effects at different concentrations. All the five AMPs shows a similar trend with the higher the concentration of the protein was, the more antibacterial effective it was. The Fusion had the best antibacterial effect, with 15 μM of the protein inhibiting bacterial growth by 75%. It shows that our AMPs do have a significant antibacterial function, and the antibacterial function of the Fusion is the best. A detailed analysis of the antibacterial effect of each AMP were given below.

As we have seen in Figure 1, the higher the concentration of the Hydramacin-1was, the more effective it was. When the concentration of Hydramacin-1 reached 8μM, it could sterilize and inhibit bacteria to OD₆₀₀ absorbance value 0.5 and below. When the concentration of Hydramacin-1 reaches 15μM, it can sterilize and inhibit bacteria growth to the OD₆₀₀ absorbance value of 0.25 or below, and its antimicrobial effect is even better than that of positive control group kanamycin.

The figure 2 shows that when the concentration of Spheniscin-2 reaches 25μM, its OD₆₀₀ absorbance value drops to about 0.5, which means that from this concentration, the use of Spheniscin-2 will have a more significant effect. When its concentration reaches 50 μM, the antimicrobial effect of Spheniscin-2 is even similar to the antimicrobial effect of the positive control kanamycin. Then, according to the trend, the antibacterial effect of Spheniscin-2 will be better than that of kanamycin when it is further concentrated to a higher concentration.

According to the figure 3, the decreasing trend of the OD₆₀₀ absorbance value of LL-37 was relatively flat overall, showing the negative relationship between AMPs concentration and OD₆₀₀ absorbance value. It is noteworthy that when the concentration of LL-37 is 25μM and 50μM, the difference between them is vast, and the OD₆₀₀ absorbance value drops from about 0.5 to about 0.25. When the concentration of LL-37 reached 50 μM, its antibacterial effect was even significantly better than that of the positive control group using kanamycin. Therefore, the optimal working concentration of LL-37 antimicrobial peptide should be between 25 μM and 50 μM.

The bar graph in Figure 4 is very similar to the bar graph of LL-37, but much flatter and Sparamosin 26-54 is also a more effective antimicrobial at higher concentrations. However, according to this graph, the concentration required to inhibit bacterial growth with Sparamosin_26-54 effectively would be relatively higher than above three AMPs.

As the graph shows in Figure 5, overall, the higher concentration the Fusion is, the stronger its ability to inhibit bacterial growth. However, similar to the pre-experiments with Fusion, the AMP at a concentration of 4μM had a better ability to inhibit bacterial growth than the antimicrobial peptide at a concentration of 6μM, further confirming the ability of Fusion antimicrobial peptide to inhibit bacterial growth at some of the lower concentrations than at around the median. Moreover, as the concentration of Fusion antimicrobial peptide increased, there was a decrease in its OD₆₀₀ absorbance that indicate a strong antibacterial effect. More obviously, when the concentration was increased from 10 μM to 15 μM, its OD₆₀₀ absorbance value dropped abruptly from about 0.6 to 0.3, a value even lower than that of the kanamycin positive control group. Further analysis of the data combined with 15 μM, 20 μM, and 25 μM, it can be inferred that after the concentration of Fusion antimicrobial peptide reached 15μM, its antimicrobial effect was more stable and did not change drastically due to increasing concentration. Therefore, its antimicrobial effect was slightly more effective than that of kanamycin.