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

Ekkalak Ploydee,Saipin Chaiyanan

doi:10.1155/2014/162173

Abstract

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 withLactobacillus pentosusL7 to lactic acid. At a pH of3.9±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 proteolyticBacillus thuringiensisSA. After decalcification and deproteinization of the shrimp shells, residual calcium and crude protein of shrimp chitin flakes were1.7±0.4% and3.8±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 of1.6±0.6%,0.4±0.3%, and83.2±1.5%, respectively. The viscosity of chitosan prepared from chitin extracted by this two-step biological process was1,007±14.7 mPa·s, whereas chitosan prepared from chemically processed chitin had a viscosity of323±15.6 mPa·s, indicating that biologically purified chitin gave chitosan with a high quality.

Highlights

The main unutilized biomass from the shrimp packaging and processing industries is heads and body carapaces, which constitute 45–50% of the wet weight of fresh shrimps [1,2,3,4,5]
The objective of this work was to investigate a novel process for producing high viscosity chitosan from chitin isolated by two-step purification: the first step using the lactic acid bacterium L. pentosus L7, and the second step using the protease-producing bacterium B. thuringiensis SA
The cost of the culture media for L. pentosus L7 and B. thuringiensis SA used in the process was a high investment

Summary

Introduction

The main unutilized biomass from the shrimp packaging and processing industries is heads and body carapaces, which constitute 45–50% of the wet weight of fresh shrimps [1,2,3,4,5]. About 20–40% of shrimp biowaste consists of chitin encrusted with calcium carbonate, protein, astaxanthin, and lipid residues [6, 7]. Shrimp biowaste is often treated in landfills or discarded in sea water, resulting in ecological problems in coastal areas, whereas a small part is used as a major component in chicken or fish feed, mixed with other agricultural raw materials [6]. The exoskeletons of crustacean waste from the seafood industry are traditionally used to prepare commercial chitin and chitosan [8, 9]. Β-(1, 4)-linked N-acetyl glucosamine (GlcNAc), is the most abundant natural polysaccharide on earth after cellulose [10, 11]. Chitin can be converted to chitosan (β-(1, 4)-linked linear polymer of 2-acetamide-2-deoxy-β-D-glucose) by deacetylation with concentrated NaOH. The viscosity of chitosan depends strongly on the viscosity of the “preproduct” chitin [6]

Objectives

Methods

Results

Conclusion