# Enhanced Enzymatic Degradability of Livestock Blood Pretreated with Ultrasonic Technique
## 3 Results and Discussion
### Enzymatic Degradation of Untreated Livestock Blood  
2.1 Effects on Protein Reduction and Amino Acid Conversion for Livestock Blood Depending on Enzyme Type  
In previous studies, various chemical methods, including the use of acids or alkalis, have been utilized to convert proteins into amino acids [4; 36]. However, employing such chemical methods for protein breakdown necessitates additional washing steps; hence, using chemical reagents in the utilization of Livestock blood as a resource may incur additional costs [37]. Therefore, in this study, we aimed to streamline the process and ensure cost-effectiveness by opting for a biological approach that relies on enzymes derived from microorganisms to circumvent chemical treatment. Alcalase(r). While most of the proteins appeared to be degraded within 2 h of treatment, the increase in amino acids did not necessarily correlate with the decrease in proteins. This suggests that the reduction in protein concentration does not necessarily Lead to an increased amino acid concentration, and the protein molecules may exist in a precipitate form or may not have been fully broken down into amino acids. The use of the Flavourzyme(r) resulted in a significantly Lower protein degradation rate compared with the endo-type enzymes because exo-type enzymes primarily cleave peptide bonds on the outer regions of proteins. Consequently, when considering the total protein content, a relatively smaller amount of degraded proteins was measured. The combination of endo- and exo-type enzymes Led to the observation that, with time, proteins steadily decreased, and amino acid conversion occurred more effectively compared with the individual use of each enzyme. This suggests that when endo- and exo-type enzymes are used in combination, the endo-type enzyme initially breaks down proteins to the peptide Level, upon which the exo-type enzyme cleaves peptide bonds from the exterior, resulting in the efficient generation of Low molecular weight peptides and amino acids. A comparison of the changes in protein concentration in the ultrasound-treated blood samples, based on each enzyme treatment (Table 4), revealed that the single use of Savinase(r) resulted in the highest protein reduction rate, with the concentration of the remaining proteins after 4 h of reaction reduced to 12.5 mg/mL. In contrast, the single use of Flavourzyme(r) resulted in the Lowest protein reduction rate; the protein concentration decreased to 78.4 mg/mL. However, the single use of Flavourzyme(r) increased the amino acid concentration to 56.9 mg/mL, indicating the highest amino acid generation. Comparing the protein reduction rate relative to the initial protein concentration yielded the following order: Savinase(r) > Alcalase(r) > Savinase(r) + Flavourzyme(r) > Alcalase(r) + Flavourzyme(r) > Flavourzyme(r). The highest amino acid conversion rate relative to the initial protein concentration was exhibited by Flavourzyme(r) and Savinase(r) + Flavourzyme(r) at very similar Levels, followed by Alcalase(r) + Flavourzyme(r), Savinase(r), and Alcalase(r). Flavourzyme(r) exhibited the highest overall amino acid conversion rate compared to other enzymes. However, exo-type enzymes are economically more expensive than endo-type enzymes, making them Less cost-effective for Large-scale industrial processes. On the other hand, when used individually, endo-type enzymes have Lower amino acid conversion rates and are not suitable for amino acid production. In the combined use of exo-type and endo-type enzymes, the mixture was found to have an amino acid conversion rate comparable to that of a single use of exo-type enzymes. Additionally, considering the