Department of Microbiology, Vidyasagar University, Midnapore, West Bengal 721102, India.
Centre for Life Sciences, Vidyasagar University, Midnapore, West Bengal 721102, India.
Int J Biol Macromol. 2023 Jul 31;244:125389. doi: 10.1016/j.ijbiomac.2023.125389. Epub 2023 Jun 17.
Commercial chitosan manufacturing process relies on strong chemical treatment on chitin that generates chitosan with undesirable properties and leads to environmental pollution. To overcome the adverse consequences, enzymatic chitosan preparation from chitin was undertaken in the current study. A potent chitin deacetylase (CDA) producing bacterial strain was screened and subsequently identified as Alcaligens faecalis CS4. After optimization 40.69 U/mL of CDA production was achieved. By treating the organically extracted chitin with partially purified CDA chitosan yield of 19.04 % was attained having 71 % solubility, 74.9 % degree of deacetylation, 21.16 % crystallinity index, 246.4 kDa molecular weight and 298 °C highest-decomposition temperature. FTIR and XRD analysis revealed characteristics peaks respectively within 870-3425 cm wavenumber and 10°-20°, for enzymatically and chemically extracted (commercial) chitosan that endorses their structural similarity which validated through electron microscopic study. At 10 mg/mL chitosan concentration 65.49 % DPPH radical scavenging activity endorsed its antioxidant potential. Minimum inhibitory concentration of chitosan was 0.675, 1.75, 0.33 and 0.75 mg/mL for Streptococcus mutans, Enterococcus faecalis, Escherichia coli and Vibrio sp., respectively. Mucoadhesiveness and cholesterol binding properties were also exhibited by extracted chitosan. The present study opens a new vista for eco-friendly extraction of chitosan from chitin that is proficient and sustainable in environmental perspective.
商业壳聚糖的制造过程依赖于对甲壳素的强烈化学处理，这种处理会生成具有不良性质的壳聚糖，并导致环境污染。为了克服这些不利后果，本研究采用酶法从甲壳素制备壳聚糖。筛选出一种产强力几丁质脱乙酰酶（CDA）的细菌菌株，并随后鉴定为粪产碱杆菌 CS4。经过优化，获得了 40.69 U/mL 的 CDA 产量。通过用部分纯化的 CDA 处理有机提取的甲壳素，壳聚糖的产率达到 19.04%，溶解度为 71%，脱乙酰度为 74.9%，结晶度指数为 21.16%，分子量为 211.6 kDa，最高分解温度为 298°C。FTIR 和 XRD 分析分别在 870-3425 cm 波数和 10°-20°范围内显示出特征峰，用于酶法和化学法（商业）提取的壳聚糖，这证明了它们的结构相似性，这一观点通过电子显微镜研究得到了验证。在壳聚糖浓度为 10 mg/mL 时，壳聚糖对 DPPH 自由基的清除率为 65.49%，这表明其具有抗氧化潜力。壳聚糖对变形链球菌、粪肠球菌、大肠杆菌和弧菌的最小抑菌浓度分别为 0.675、1.75、0.33 和 0.75 mg/mL。提取的壳聚糖还具有粘膜粘附性和胆固醇结合特性。本研究为从甲壳素中提取壳聚糖开辟了新的途径，从环保角度来看，这种方法具有高效和可持续性。
