Author, Institution: Renata Biškauskaitė-Ulinskė, Kaunas University of Technology
Science area, field of science: Technological Sciences, Chemical Engineering, T005
Research Supervisor: Virgilijus Valeika (Kaunas University of Technology, Technological Sciences, Chemical Engineering, T005)
Dissertation Defence Board of Chemical Engineering Science Field:
Prof. Dr. Hab. Juozas Vidas Gražulevičius (Kaunas University of Technology, Technological Sciences, Chemical Engineering, T005) – chairperson
Dr. Carmen Gaidau (The National Research and Development Institute for Textiles and Leather, Romania, Technological Sciences, Materials Engineering, T008)
Assoc. Prof. Dr. Ilona Jonuškienė (Kaunas University of Technology, Technological Sciences, Chemical Engineering, T005)
Prof. Dr. Ramunė Rutkaitė (Kaunas University of Technology, Technological Sciences, Chemical Engineering, T005)
Prof. Dr. Jūratė Šiugždaitė (Lithuanian University of Health Sciences, Agricultural Sciences, Veterinary, A002)
Dissertation defence meeting will be at Rectorate Hall of Kaunas University of Technology (K. Donelaičio 73 – 402, Kaunas)
The doctoral dissertation is available at the library of Kaunas University of Technology (Gedimino 50, Kaunas) and on the internet: R. Biškauskaitė-Ulinskė el.dissertation.pdf
© R. Biškauskaitė-Ulinskė, 2025 “The text of the thesis may not be copied, distributed, published, made public, including by making it publicly available on computer networks (Internet), reproduced in any form or by any means, including, but not limited to, electronic, mechanical or other means. Pursuant to Article 25(1) of the Law on Copyright and Related Rights of the Republic of Lithuania, a person with a disability who has difficulties in reading a document of a thesis published on the Internet, and insofar as this is justified by a particular disability, shall request that the document be made available in an alternative form by e-mail to doktorantura@ktu.lt.”
Annotation: Due to their specific properties, enzymes and enzyme preparations are receiving increasing attention from from researchers across various scientific fields, including leather processing. Currently, the application of enzymes is being investigated not only for the traditional bating process, but also in other stages of leather processing, such as unhairing and soaking. Despite ongoing research, the use of enzymes in these additional processes remains limited, primarily due to a lack of knowledge regarding the effects of proteases on leather structure and subsequent processing outcomes. This doctoral dissertation investigates the application of newly isolated enzymes in leather preparation processes, as well as the use of enzyme preparations in a newly developed salt-free pickling–bating method, chromed leather treatment, neutralization, and dyeing. It was found that the enzyme from Bacillus halodurans BCRC 910501 accelerates the soaking process while maintaining final product properties comparable to conventionally processed leather. An alternative salt-free pickling–bating method was developed and studied, using p-toluenesulfonic acid monohydrate. This new method shortens the total processing time by nearly two hours, reduces energy consumption, and lowers wastewater pollutant levels. The effect of enzymatic preparations on chromed leather treatment and neutralization of semi-finished leather was evaluated. The results indicate that enzymes enhance chromium uptake and dye penetration, although their use during neutralization is ineffective. The dyeing process with enzymes was also studied – dyeing kinetics, penetration, color characteristics, and a possible mechanism of the process were established. The dissertation presents results on enzyme activity, their application in specific stages of leather processing, and proposes a practical leather processing methodology suitable for industrial implementation.