Production of High Viscosity Chitosan from Biologically Purified Chitin Isolated by Microbial Fermentation and Deproteinization

Abstract EN

The objective of this study was to produce high viscosity chitosan from shrimp chitin prepared by using a two-step biological treatment process: decalcification and deproteinization.

Glucose was fermented with Lactobacillus pentosus L7 to lactic acid.

At a pH of 3.9 ± 0.1 , the calcium carbonate of the shells was solubilized in 48 hours.

The amounts of residual calcium in the form of ash ( 1.4 ± 0.5 % ) and crude protein ( 23.2 ± 2.5 % ) were further eliminated by the activity of proteolytic Bacillus thuringiensis SA.

After decalcification and deproteinization of the shrimp shells, residual calcium and crude protein of shrimp chitin flakes were 1.7 ± 0.4 % and 3.8 ± 1.3 % , respectively.

Chitin was deacetylated with 50% NaOH at 121°C for 5 hours.

After deacetylation, the chitosan had residual calcium, crude protein content, and degree of acetylation of 1.6 ± 0.6 % , 0.4 ± 0.3 % , and 83.2 ± 1.5 % , respectively.

The viscosity of chitosan prepared from chitin extracted by this two-step biological process was 1,007 ± 14.7 m P a · s , whereas chitosan prepared from chemically processed chitin had a viscosity of 323 ± 15.6 m P a · s , indicating that biologically purified chitin gave chitosan with a high quality.