دانشگاه اصفهان زیست شناسی میکروبی 3060-7647 14 55 2025 11 22 Improving antioxidant properties of fermented poultry slaughterhouse byproducts under proteolytic isolated bacteria Improving antioxidant properties of fermented poultry slaughterhouse byproducts under proteolytic isolated bacteria 35 46 29129 10.22108/bjm.2024.142997.1616 FA Reyhaneh Zakeri Department of Biotechnology, Faculty of Biological Sciences, Alzahra University Tayebeh Tayebeh Hadi Toranposhti Department of Biotechnology, Faculty of Biological Sciences, Alzahra University,Tehran, Iran Fakhrisadat Hosseini Department of Biotechnology, Faculty of Biological Sciences, Alzahra University,Tehran, Iran 0000-0002-8368-1133 Journal Article 2024 10 11 The disposal of slaughterhouse waste such as feather meal, blood meal, meat and bone meal and poultry meal poses biological problems. In addition, these wastes contain different amounts of proteins that can be used to improve the nutritional value of these low-value products through microbial processes. In this study, proteolytic isolates, slaughterhouse powder, blood meal, meat meal, and a mixture of meat and blood and bone meal were first isolated from slaughterhouse waste. Then, proteolytic isolates were identified and isolates with better protease properties than other isolates were used for fermentation of the waste. Immersion fermentation was performed at 30 °C and 150 rpm for 5 days by three isolates B4, C3 and A5 with better protease properties than other isolates. The protein content and degree of hydrolysis of the isolates were then measured in 4 sources of slaughterhouse powder, meat powder, blood meal and a mixture of meat and blood and bone meal from slaughterhouse waste. Antioxidant tests were performed based on DPPH radical scavenging and iron chelation methods. Finally, molecular techniques and phylogenetic trees were used to identify the selected strain. The results showed that all hydrolyzed protein wastes removed DPPH and chelated free radicals and had antioxidant properties, and hydrolysis of the wastes could be used for feeding. The disposal of slaughterhouse waste such as feather meal, blood meal, meat and bone meal and poultry meal poses biological problems. In addition, these wastes contain different amounts of proteins that can be used to improve the nutritional value of these low-value products through microbial processes. In this study, proteolytic isolates, slaughterhouse powder, blood meal, meat meal, and a mixture of meat and blood and bone meal were first isolated from slaughterhouse waste. Then, proteolytic isolates were identified and isolates with better protease properties than other isolates were used for fermentation of the waste. Immersion fermentation was performed at 30 °C and 150 rpm for 5 days by three isolates B4, C3 and A5 with better protease properties than other isolates. The protein content and degree of hydrolysis of the isolates were then measured in 4 sources of slaughterhouse powder, meat powder, blood meal and a mixture of meat and blood and bone meal from slaughterhouse waste. Antioxidant tests were performed based on DPPH radical scavenging and iron chelation methods. Finally, molecular techniques and phylogenetic trees were used to identify the selected strain. The results showed that all hydrolyzed protein wastes removed DPPH and chelated free radicals and had antioxidant properties, and hydrolysis of the wastes could be used for feeding. https://bjm.ui.ac.ir/article_29129_11d75911201b7bc8e2a6a06791dc94ee.pdf