Centre for Drug Discovery and Development, Sathyabama Institute of Science and Technology, Chennai, Tamilnadu, 600119, India.
Department of Biotechnology, School of Bio and Chemical Engineering, Sathyabama Institute of Science and Technology, Chennai, Tamilnadu, India.
Sci Rep. 2022 Mar 21;12(1):4792. doi: 10.1038/s41598-022-08371-1.
Marine wastes pose a great threat to the ecosystem leading to severe environmental hazards and health issues particularly the shellfish wastes. The shellfish waste which contains half of the amount of chitin can be efficiently transformed into useful products. Various approaches for the hydrolysis of chitin like physical, chemical, and enzymatic processes are there. Still, the use of enzyme chitinase is well documented as an effective and eco-friendly method. The present study summarizes the isolation of chitinase enzyme producing bacteria from different shrimp waste disposal sites in Parangipettai (India), and the possible use of an enzyme hydrolyzate as an immunostimulant to Asian Seabass (Lates calcarifer). The potential chitinase-producing bacteria were identified by 16S rRNA gene sequencing as Stenotrophomonas maltophilia. After purification, the chitinase specific activity was 5.01 (U/ml) and the protein content was 72 mg and the recovery rate was 48.06%. The optimum pH and temperature for the chitinolytic activity were 6.5 and at 35-50 °C, respectively. The animal experiment trial was done with our feed supplements which included 0.0 (control), 0.5%, 1% and 2% of chitin degraded product. All the supplementary feed had an optimal 42% (w/w) of crude protein. The feed protein level was 41-43% on average and gross energy was 13-17 kcal/g and the feed was observed to exhibit a significantly higher (p < 0.05) survival rate, condition factor, specific growth rates, and body weight gain was also found to be promising compared to other fishes fed with control diet only. The red blood cells (RBC) and white blood cell (WBC) counts were found to increase significantly after being challenged with infection in animals fed with chitin derivatives from 1st week to 3rd week when compared to the control. The hematocrit (Hct) values were low on the 2nd and 3rd week in infected fish fed with chitin derivatives. This low level was due to infection lyses of the red blood cells and increased nitro blue tetrazolium reduction. The control diet-fed fish showed 70% mortality but the chitin derivative supplemented fishes showed only 20% mortality post-infection. The results of the study encompass that the use of chitin-derivate enriched feed further is taken into large-scale approaches thereby benefitting the aquaculture sector.
海洋废弃物对生态系统构成了巨大威胁，导致严重的环境危害和健康问题，尤其是贝类废弃物。贝类废弃物中含有一半的壳聚糖量，可以有效地转化为有用的产品。有许多种方法可以水解壳聚糖，如物理、化学和酶法等。然而，使用酶壳聚糖酶作为一种有效且环保的方法已有充分的记录。本研究总结了从印度帕兰吉佩泰（Parangipettai）不同虾类废物处理场分离产壳聚糖酶细菌的情况，以及将酶水解产物用作刺激亚洲尖吻鲈（Lates calcarifer）免疫的可能性。通过 16S rRNA 基因测序鉴定潜在的产壳聚糖细菌为嗜麦芽寡养单胞菌（Stenotrophomonas maltophilia）。经过纯化，壳聚糖酶的比活力为 5.01（U/ml），蛋白含量为 72mg，回收率为 48.06%。最适 pH 和温度分别为 6.5 和 35-50°C。动物实验用我们的饲料补充剂进行，其中包括 0.0（对照）、0.5%、1%和 2%的壳聚糖降解产物。所有补充饲料的粗蛋白含量最佳为 42%（w/w）。饲料蛋白水平平均为 41-43%，总能为 13-17kcal/g，与仅用对照饲料喂养的其他鱼类相比，观察到的存活率、条件系数、特定生长率和体重增长率显著更高（p<0.05）。与仅用对照饲料喂养的鱼类相比，在第 1 周到第 3 周受到感染挑战时，用壳聚糖衍生物喂养的动物的红细胞（RBC）和白细胞（WBC）计数显著增加。在感染壳聚糖衍生物的鱼类中，第 2 周和第 3 周的血细胞比容（Hct）值较低。这一低值是由于红细胞的感染溶解和增加的硝基蓝四唑还原。用对照饲料喂养的鱼类死亡率为 70%，但用壳聚糖衍生物补充饲料喂养的鱼类感染后死亡率仅为 20%。研究结果表明，进一步使用富含壳聚糖衍生物的饲料将采用大规模方法，从而使水产养殖部门受益。
