Henryk Struszczyk

GPC Studies of Chitosan Degradation

Abstract Investigated were the changes in the molecular character of chitosan resulting from its degradation by the hydrolytic, radiation, and hydrolytic-enzymatic methods. It was found that under the influence of γ-60Co radiation, degradation proceeds in a manner implying a random breakup of the polymer chains with a systematic decline of sample polydispersity with increasing irradiation dose. In the hydrolytic and hydrolytic-enzymatic degradation processes the differences in the resulting changes depend on chain length. While the short macromolecules degrade similarly as by radiation, the longer chains degrade less readily, which can be inferred from the molecular weight distribution curves as well as from the polydispersity

GPC STUDIES ON BACTERIAL CELLULOSE

The aim of the present study was to examine the effect of time duration of bacterial cellulose (BC) biosynthesis as well as the culture medium composition on molecular parameters of the obtained polymer. It was found that the degree of polymerization of BC increases as the duration of biosynthesis is prolonged up to 6 days. A further prolongation of the process to 28 days lowers the degree of polymerization (DP) value and increases polydispersity. An examination of the effect of culture medium composition on the biosynthesis pointed out that the course of the process is mainly influenced by the chemical nature of the carbon source. The best results for molecular parameters were obtained for a medium containing 4% of glucose.

Biotransformation of Cellulose: GPC Studies†

Abstract We are interested in developing a new manufacturing process for cellulosic fiber based on biotransformation of cellulose to make it soluble in NaOH solutions. The enzymes used are cel-lulases extracted from Aspergillus niger by deep fermentation of the mycelium. The effect of the biotransformation process conditions on cellulose molecular structure and solubility in NaOH solutions was investigated, the overall objective being to optimize the process. The biotransformation process involves partial depolymerization of the cellulose with associated changes in the physical and chemical parameters of the polymer. The changes were determined by gel permeation chromatography (GPC). The effect of biotransformation parameters such as enzyme concentration, temperature and time of enzymatic action on the molecular properties of cellulose were studied. The effect of pretreatment methods such as mechanical or radiation were also determined.