Original scientific paper

https://doi.org/10.17559/TV-20150427225158

High-risk bio-waste processing by alkaline hydrolysis and isolation of amino acids

Sanja Kalambura orcid.org/0000-0002-4337-4892 ; University of Applied Sciences Velika Gorica, Zagrebačka 5, 10 410 Velika Gorica, Croatia
Tajana Krička orcid.org/0000-0002-8044-4861 ; Faculty of Agriculture, University of Zagreb Svetošimunska 25, 10 000 Zagreb, Croatia
Darko Kiš ; Faculty of Agriculture, J. J. Strossmayer University of Osijek, Kralja Petra Svačića 1d, 31 000 Osijek, Croatia
Sunčica Guberac ; Faculty of Agriculture, J. J. Strossmayer University of Osijek, Kralja Petra Svačića 1d, 31 000 Osijek, Croatia
Dražan Kozak orcid.org/0000-0001-5245-4686 ; Mechanical Engineering Faculty in Slavonski Brod, J. J. Strossmayer University of Osijek, Trg Ivane Brlic Mazuranic 2, 35000 Slavonski Brod, Croatia
Antun Stoić ; Mechanical Engineering Faculty in Slavonski Brod, J. J. Strossmayer University of Osijek, Trg Ivane Brlic Mazuranic 2, 35000 Slavonski Brod, Croatia

Abstract

Slaughterhouse waste can be very dangerous and potential risk for animal and human health. Brains and spinal cords are deemed high-risk substances and can be infected with prions; their treatment is therefore only possible in strictly controlled conditions. One of the methods which can achieve the necessary reduction in health risk is alkaline hydrolysis. Standard alkaline hydrolysis is at 150 °C, 3-6 hours, and 4 bars. In this investigation focus was on different alkaline conditions: temperature (135 °C, 150 °C, 153 °C), time (2, 3, 6 hours), and base (NaOH and KOH) due to the fact that amino acids are sensitive to variations on temperature, pressure and base media. Analyzed amino acid composition of hydrolyzed material at different testing conditions show successful hydrolysis. The highest value of protein, which is generally relatively low, was achieved with NaOH at a temperature of 135 °C and time of 2 hours, whereas in the reaction with KOH the highest obtained value was achieved at 150 °C and 3 hours. The dry substance was increasing with time, and the highest value was achieved at the temperature of 150 °C and time 6 hours for both bases (NaOH, and KOH). Most of the amino acids went full racemization during the process; especially in D-amino acids like aspartic acid, glutamic acid, tryptophan and isoleucine. Lysine shows higher resistance to alkaline medium than other amino acids. Isolation of certain amino acids, like: asparagine, glutamic acid, glycine, alanine, and leucine, is possible because they show higher concentrations in hydrolysates.

Keywords

alkaline hydrolysis parameters; health risks; slaughterhouse waste; waste management

Hrčak ID:

169366

URI

https://hrcak.srce.hr/169366

Publication date:

29.11.2016.

Article data in other languages: croatian

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