Effect of Chitosan Deacetylation on Its Affinity to Type III Collagen: A Molecular Dynamics Study

The ability to form strong intermolecular interactions by linear glucosamine polysaccharides with collagen is strictly related to their nonlinear dynamic behavior and hence bio-lubricating features. Type III collagen plays a crucial role in tissue regeneration, and its presence in the articular cartilage affects its bio-technical features. In this study, the molecular dynamics methodology was applied to evaluate the effect of deacetylation degree on the chitosan affinity to type III collagen. The computational procedure employed docking and geometry optimizations of different chitosan structures characterized by randomly distributed deacetylated groups. The eight different degrees of deacetylation from 12.5% to 100% were taken into account. We found an increasing linear trend (R2 = 0.97) between deacetylation degree and the collagen–chitosan interaction energy. This can be explained by replacing weak hydrophobic contacts with more stable hydrogen bonds involving amino groups in N-deacetylated chitosan moieties. In this study, the properties of chitosan were compared with hyaluronic acid, which is a natural component of synovial fluid and cartilage. As we found, when the degree of deacetylation of chitosan was greater than 0.4, it exhibited a higher affinity for collagen than in the case of hyaluronic acid.

Synthesis and antibacterial activity of chitosan membrane from shrimp shell waste

Synthesis and antibacterial activity of chitosan membrane was investigated. Chitosan membrane have been successfully by simple method from chitosan extracted from shrimp shell waste. Extraction of chitosan was carried out in four steps: demineralization, deproteinization, decolorization and deacetylation of chitin. The effect of deacetylation temperature on deacetylation process was studied. The results shown that the increase of deacetylation temperature from 30°C to 90°C causes the increase of chitosan deacetylation degree (DD). The increase of deacetylation temperature cause the increment of OH- attack to the amino group thus realizing the effective deacetylation of chitin. The highest chitosan DD was up to 77.99% is achieved under the deacetylation temperature from 90°C and the occurrence of deacetylation structurally demonstrated by the Fourier transform infrared (FTIR) and the XRD characterization. The antimicrobial test results used S. epidermidis and P. acne of chitosan membrane at various deacetylation temperature conditions indicated that no bacterial activity for all variants.

Pengaruh Variasi Konsentrasi NaOH Terhadap Nilai Derajat Deasetilasi Kitosan dari Limbah Cangkang Kerang Hijau (Perna viridis L)

Chitin which is the result of processing from green conch shell waste can be transformed into chitosan through a deacetylation process using variations in the concentration of NaOH. This study aims to determine the optimum conditions of variations in base concentration to the value of the degree of deacetylation of chitosan. The types of bases used are NaOH with the concentration variations of 50%, 55%, and 60%. Chitosan obtained was calculated the yield and characterized using FTIR. The results showed the optimum condition of the value of chitosan deacetylation degree was achieved by using 60% NaOH which produced the highest deacetylation degree value of 76.5%. Keywords: Green mussels shell, chitin, chitosan, deacetylation

Effect of Heterogeneous Deacetylation on the Properties of Northern Shrimp Chitin and Chitosan

The effect of alkaline treatment of shrimp chitin on the molecular weight, the degree of deacetylation and degree of crystallinity of the resulting chitosan is studied. The viscosity of chitosan solutions from repeatedly deacetylated chitin is studied. It is shown that repeated treatment of chitin/chitosan with alkali causes the destruction of polysaccharide macromolecules. After four-time deacetylation and one-time deacetylation of chitin/chitosan for four hours, the molecular weight of the polysaccharide decreases by ten times. The maximum degree of chitosan deacetylation under experimental conditions was 92.0 -92.5%. The diffractograms of chitin and chitosan from the Northern shrimp are of the form typical for samples containing an amorphous phase in addition to a crystalline phase. The degree of crystallinity of chitin from Northern shrimp was 40.8%, of chitosan samples after one-, two-, and three-time deacetylation was 62-65%. For a sample of chitosan obtained after four-time deacetylation, recrystallization, and drying in a freeze dryer, the degree of crystallinity is close to the degree of crystallinity of shrimp chitin. The investigated acetic acid chitosan solutions with a concentration of 5% (wt.) and the chitosan molecular weight of 250, 160 and 130 kDa in their rheological properties are liquid-like non-Newtonian systems, their viscosity decreasing with increasing shear stress. After four-time deacetylation of chitin, the viscosity of chitosan solutions practically does not change with increasing shear stress, which apparently can be due to a significant decrease in the molecular weight of chitosan under these conditions.

Pengaruh Konsentrasi NaOH pada Deasetilasi Kitin dari Cangkang Udang Putih (Litopenaeus vannamei) dan Aktivitasnya pada Air Gambut

The potential of shrimp shells as a source of chitosan for the processing of West Kalimantan peat water has been studied. Chitin as a precursor of chitosan was extracted from the shrimp shells by means of deproteination and demineralization processes. Deproteination was performed by suspending the shrimp shells to 3,5% NaOH at 65oC for 4 hours. The demineralization process was done by using 1.5M HCl at the same temperature and time. Difference concentration of NaOH (30 – 70%) was applied in deacetylation of chitin to chitosan in order to obtain informations on the effect of base on chitosan deacetylation degree. The results obtained showed that the higher the concentration of NaOH, the higher the chitosan deacetylation degree. The highest deacetylation degree was obtained when chitin was deacetylation using 70% NaOH with the value of 87.5%. Performance of the chitosan was examined in the peat water treatment process. Some test parameters showed that chitosan added to peat water causes coagulation and flocculation with peat water components. This was indicated by the decreasing in color parameter value of 337 PtCo, the decreasing of organic substances in peat water of 10 mg/L and the increasing of pH value to 7.9. Keywords: chitin, chitosan, coagulation, flocculation, peat water Abstrak Potensi cangkang udang putih sebagai sumber kitosan untuk proses pengolahan air gambut Kalimantan Barat telah dipelajari. Kitin sebagai prekursor dari kitosan diekstrak dari kulit udang putih melalui dua tahap yaitu deproteinasi dan demineralisasi. Deproteinasi dilakukan dengan menggunakan NaOH 3,5% pada suhu 65oC selama 4 jam dan dilanjutkan dengan proses demineralisasi menggunakan HCl 1,5M dengan suhu dan waktu yang sama. Variasi konsentrasi basa NaOH sebesar 30 – 70 % dilakukan pada proses deasetilasi kitin menjadi kitosan guna mendapatkan informasi pengaruh konsentrasi basa terhadap derajat deasetilasi kitosan. Hasil yang diperoleh menunjukkan bahwa semakin tinggi konsentrasi basa NaOH yang digunakan maka semakin tinggi pula derajat deasetilasi kitosan yang diperoleh. Konversi tertinggi diperoleh ketika kitin dideasetilasi menggunakan NaOH 70% dengan nilai derajat deasetilasi sebesar 87,5%. Performa kitosan hasil deasetilasi terbaik diuji pada proses pengolahan air gambut. Beberapa parameter uji menunjukkan bahwa kitosan yang ditambahkan pada air gambut menyebabkan terjadinya koagulasi dan flokulasi dengan komponen air gambut. Hal ini ditandai dengan menurunnya nilai parameter warna sebesar 337 PtCo kandungan zat organik di dalam air gambut sebesar 10 mg/L dan nilai pH yang meningkat menjadi 7,9. Kata kunci: kitin, kitosan, koagulasi, flokulasi, air gambut

Evaluation of the degree of chitosan deacetylation via induced-electrical properties

The properties and functionalities of chitosan are closely related to its degree of deacetylation (DD).