Use of a fractional factorial design to study the effects of experimental factors on the chitin deacetylation.

International journal of biological macromolecules

PubMedID: 24997447

Younes I, Ghorbel-Bellaaj O, Chaabouni M, Rinaudo M, Souard F, Vanhaverbeke C, Jellouli K, Nasri M. Use of a fractional factorial design to study the effects of experimental factors on the chitin deacetylation. Int J Biol Macromol. 2014;.
Chitosan is obtained by deacetylation of chitin. Chitosan versatility is directly related to the polymer's characteristics depending on the deacetylation process. The aim of this research was to study the parameters influencing deacetylation and to elucidate their effect on acetylation degree (DA) and molecular weight (MW). The effect on chitosan DA was investigated using a fractional factorial design 2(7-3) with seven factors and two variation levels. The tested factors were: X1=number of successive baths, X2=reaction time, X3=temperature, X4=alkali reagent, X5=sodium borohydride, X6=the atmospheric conditions and X7=alkali concentration. A mathematical model was investigated corresponding to the following relation y=7.469-1.344 X1-1.094 X2-3.094 X3+1.906 X4+0.656 X5+0.906 X6-1.031 X7+0.469 X1X2-0.781 X3X4+0.906 X1X3X4 with R(2)=0.99. This model allows fixing experimental conditions for each desired DA. To study the effect on chitosan MW, only atmospheric conditions and use of sodium borohydride as an oxygen scavenger were investigated. The use of sodium borohydride and nitrogen atmosphere was found to have a protective effect against chitosan degradation during deacetylation.