Production of Antimicrobial Films by Incorporation of Partially Purified Lysozyme into Biodegradable Films of Crude Exopolysaccharides Obtained from Aureobasidium pullulans Fermentation

Nilay Kandemir¹, Ahmet Yemenicioğlu²*, Çiğdem Mecitoğlu², Zehra Seda Elmacı³, Alper Arslanoğlu³, Yekta Göksungur¹ and Taner Baysal<sup>1

1</sup>Department of Food Engineering, Faculty of Engineering, Ege University, 35100 Bornova, Izmir, Turkey
²Department of Food Engineering, Faculty of Engineering, Izmir Institute of Technology, 35430 Gülbahçe Köyü, Urla, Izmir, Turkey
³Department of Biology, Faculty of Science, Izmir Institute of Technology, 35430 Gülbahçe Köyü, Urla, Izmir, Turkey

Article history:
Received January 25, 2005
Accepted April 7, 2005

Key words:
lysozyme, exopolysaccharides, pullulan, Aureobasidium pullulans, antimicrobial films

Summary:
Antimicrobial films were produced by incorporating partially purified lysozyme into films of crude exopolysaccharides (59 % pullulan) obtained from Aureobasidium pullulans fermentation. After film making, the films containing lysozyme at 100, 260, 520 and 780 μg/cm² showed 23 to 70 % of their expected enzyme activities. The highest recovery of enzyme activity (65–70 %) after the film making was obtained in films prepared by incorporating lysozyme at 260 μg/cm² (1409 U/cm²). The incorporation of disodium EDTA×2H₂O and sucrose did not affect the initial lysozyme activity of the films significantly. With or without the presence of disodium EDTA×2H₂O at 52 or 520 μg/cm², lysozyme activity showed sufficient stability in the films during 21 days of cold storage. However, the presence of sucrose at 10 mg/cm² in the films caused the destabilization of part of enzyme activity (almost 35 %) at the end of storage. The combinational incorporation of lysozyme at 780 μg/cm² (4227 U/cm²) and disodium EDTA×2H₂O at 520 μg/cm² gave antimicrobial films effective on Escherichia coli. However, in the studied lysozyme concentration range the films did not show any antimicrobial activity against Lactobacillus plantarum. This study clearly showed that the partially purified lysozyme and crude exopolysaccharides from Aureobasidium pullulans may be used to obtain antimicrobial films to increase the safety of foods.

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