THE DESTRCTION OF THE COMPOSITIONS BASED ON CHITOSAN COPOLYMERS WITH ACRYLIC MONOMERS BY MICROMYCETES - Biochemistry and Biotechnology: Research and Development - page 136

R ESULTS AND A RGUMENT
As a result the (co)polymers of chitosan with vinyl monomers were obtained, and their
biodestruction ability and the one of individual homopolymers under the effect of
microscopic fungi were studied. For test-cultures standard fungi cultures for RCM (Russian
Collection of Microorganisms) were opted which are active polymer biodegraders by State
Standard 9.049-91. Table 1. presents the results of the growth assessment of the standard
micromycete cultures on the studied polymer materials. The analysis of the results shows that
the given compositons can be biodegraded by micromycetees. But for all that their this ability
differs under the effect of different fungi. The grafted chitosan with methylacrylate, block-
chitosan copolymer with methylacrylate, grafted chitosan copolymer with acrylonitril turned
out to be utilized more easily with the fungi as compared to chitosan (co)polymers with
acrylamide as the latter was biodegraded with a smaller species range of the fungi.
Aspergillus niger, A. terreus, Chaetomium globosum, Penicillium cyclopium, P. funiculosum,
Trichoderma viride were the most active destructors of all the studied compositions.
Table 2 presents the data of the stability of separate polymer-composition components
against the effect of micromycetees. A remarkable fact is that individual homopolymers
(polymethylacrylate, polyacrylonitril)which are components the biodegradable (co)polymers,
showed resitance against the effect of the fungi, meanwhile chitosan and polyacrylamid did
not. This fact proves the hypothesis we made before that the fungi resistance of polymer
compositions (copolymer or mechanical) can not be judged if only the fungi resistance of
their components is considered [19]. At the same time a series of biochemical experiments to
assess the role the role of separate ferments of the fungi such as oxidoreductase (catalase,
peroxidase) and hydrolase (chitosan, protease, esterase) in the destruction the synthesized
polymer compositions. In this series of experiments the cultures of two fungi species
Aspergillus terreus and Penicillium cyclopium which are most active biodegraders of the
studied polymer compositions. The results of the given experiment series are displayed in
tables 3 and 4.
In all the variants of the experiment a considerable increase of chitosanase activity in
comparison with the control sample which testifies to the fact that chitosan as a natural
component of the polymer compositions is a considerably available nutritional source. The
activity increase of chitosanase under the effect of fungi cultures Aspergillus terreus and
Penicillium сyclopium upon various polymer compositions was not the same, which can be
connected with physical-biochemical peculiarities of the fungi as long as with the chemical
components of the polymers (tables 3, 4). Not in all the variants of the test the synthetical part
of the compositions was used by the fungi. In a certain way this fact agrees with the
phenomenon diauxic growth of the microorganisms, i. e. the substrate which is more available
is utilized first [20]. An increase of the activity of alkaline protease Aspergillus terreus with
grafted copolymer chitosan: AA is registered, which is caused by the amide link decomposed
by the fungi protease. Thus both chitosan and the functional groups of polyacrylamide
provide the growth of the fungi. An increase of the activity of exooxydoreductase (catalase,
peroxydase) In the process of the destruction of the grafted copolymer of chitosan with
acrylonitril is also registered. These ferments are in some way also supposed to take part in
the destruction of the given polymer. So, the analysis of this series of the experiments shows
that the initial destruction stages mainly affect the natural part of the polymer compositions -