THE DESTRCTION OF THE COMPOSITIONS BASED ON CHITOSAN COPOLYMERS WITH ACRYLIC MONOMERS BY MICROMYCETES - Biochemistry and Biotechnology: Research and Development - page 134

in which - tensile strength, N/m 2 ; P - imposed load, Н; S - cross-section area of the film,
m 2 , ʵ - relative extension, %; l 0 - sample original length, cm; l 1 - sample length preceding the
break, сm.
The fungi-effect resistance was measured by State Standard 9.049-91 [11], method 1. The
given method enables to estimate the natural fungi-effect resistance of the materials, i.e. the
ability of micromycetees to use them as a nutrition source. The gist of the method consists in
the following: a certain polymeric composition is placed in Petri dishes and inoculated with a
fungi-spores suspension (1×10 6 per ml), put into the thermostat to expose at the temperature
of 28ﾱ2º С and the humidity of ≥ 95 % for 28 days.
The fungi-effect resistance was visually evaluated by marking the fungi-growth rate on
the tested polymers with points 1 - 6. The fungi were cultivated on the Capek-Docx carbon-
impoverished (1 g of sucrose per 1 l of the medium) liquid nutrient medium on the shakers
ASD - 4M (Automatic Shaking Device) at the speed of rotation of 180 promptness orb/min.
On the fourth cultivation day 2.5 g of the corresponding polymeric compositions were
added to the tested samples.
The cultivation longevity was 12 days after which the mycelium was filtered, and the
activity of the corresponding exoferments in the cultural medium was measured. The specific
activity calculation was executed per mg of protein. The control variants were the ones with
no polymeric compositions added to the nutrient medium. Each polymeric composition was
subject to two series of experiments four times.
The ferment activity was measured with the spectrophotometer (SP-2000): catalase - at
max = 240 nm [12], the s ubstrate was 30 mM hydrogen peroxide, peroxidase - at max =
535nm [13], ], the substrate was 0.03 % hydrogen peroxide and 0.1 M paraphenylendiamin
(by the Aurand method). The presence of the chitosanase activity was measured by the
spectrophotometer by their ability to saccharificate chitin/chitosan molecules. The sugar
concentration was measured by the reaction with 3,5-dinitrosalicylic acid. The method is
based on a red-coloured compound as a result of the reaction between glucose and 3,5-
dinitrosalicylic acid [14].
The measuring of protease activity was conducted by the Anson method [15]. The
ferment activity was judged by the quantity of the free tyrosine generated after substrate
proteolysis, and the tyrosine in short peptides. The esterase activity was measured by the
titrimetric method by the degree the ferment hydrolised the substance which was
dioctyladipinate stabilisated with a 2% water-solution of polyvinyl alcohol [16].
The measuring of protein was conducted by the Louri method [17].
The destruction rate of the film materials by the fungi was controlled by the change in the
physical--mechanical properties (σ,ʵ) of the films and the PMA chain-length distribution in
the (co)polymers. To identify the MM blocks and grafted chains of PMA the destruction of
the chitosan unit of copolymers with NaNO 2 was conducted [18]. PMA was identified by the
method infrared spectroscopy (spectrophotometer Infralum FT-801).
The chain-length distribution (CLD) of the blocks and grafted chains of PMA was
measured by the method of gel filtration at 40 0 C temperature on the liquid chromatograph
Prominence LC-20VP «Shimadzu» with a column set filed with polystyrol-divinylbenzol
standards with 10 6 and 10 5 Å pore size. A differential refractometer was used as a detector.
The eluent was tetrahydrofuran. The calibration was executed in accordance with narrow-
disperse standards.