Parasitic infestations on cultured fish due to the crustacean isopod Alitropus typus has been on the rise in recent years, causing large scale mortality, leading to significant economic loss to the farmer. Crustaceans are encased by an exoskeleton composed of chitin, protein and lipid microfibril frameworks, in which calcium carbonate is deposited. A strategy focused on the degradation of the exoskeletal framework utilizing nonpathogenic microorganisms that produce a wide variety of hydrolytic enzymes may be an environment-friendly and safe alternative to control these pests. The present study was aimed to formulate a microbial consortium having chitinase, protease, lipase and urease producing bacteria from seafood processing effluents that can potentially degrade the exoskeleton of A. typus. Based on the qualitative and quantitative assessment of the extracellular enzymes produced by the isolates, a novel consortium was prepared with three strains that were not antagonistic to each other and were nonpathogenic. The chitinase producing - Stenotrophomonas maltophilia and Bacillus altitudinis that produced protease and lipase as well; and non-chitinase producing Klebsiella pneumoniae were taken in the ratio of 1:1:2 respectively (10⁹ CFU/mL). The result showed 100 % mortality of the isopods within five days when applied at a concentration of 2% (v/v) of 10⁷ CFU/mL without any adverse effect on the fish host Oreochromis niloticus. Analysis of the ultrastructural alterations of the parasites by Environmental Scanning Electron microscopy (ESEM) showed noticeable exoskeletal damages. The microbial members of the consortium displayed remarkable chemotactic properties towards A. typus. The results suggest that the microbial consortium acts as a potential parasiticide that can be used for the control of A. typus infestation in aquaculture ponds., thus benefitting the aquaculture industry especially the small-scale farmers.

近年来，由等足类甲壳动物Alitropus typus引起的养殖鱼类寄生虫感染呈上升趋势，造成大规模死亡，给养殖户带来重大经济损失。甲壳类动物被外骨骼包裹，外骨骼由几丁质、蛋白质和脂质微纤维框架组成，其中沉积有碳酸钙。一种专注于利用产生多种水解酶的非病原微生物降解外骨骼框架的策略可能是控制这些害虫的一种环境友好且安全的替代方案。本研究旨在配制一种微生物聚生体，该聚生体具有来自海产品加工废水的几丁质酶、蛋白酶、脂肪酶和脲酶产生细菌，这些细菌可能会降解A. typus的外骨骼. 基于对分离物产生的细胞外酶的定性和定量评估，用三个彼此不拮抗且无致病性的菌株制备了一个新的聚生体。产生几丁质酶 -嗜麦芽窄食单胞菌和高山芽孢杆菌也产生蛋白酶和脂肪酶；肺炎克雷伯菌和不产几丁质酶的肺炎克雷伯菌分别按1:1:2（10 ⁹ CFU/mL）的比例取食。结果表明，当以 10 ⁷ CFU/mL的 2% (v/v) 浓度施用时，等足类动物在五天内 100% 死亡率，而对鱼类宿主Oreochromis niloticus没有任何不利影响. 通过环境扫描电子显微镜 (ESEM) 分析寄生虫的超微结构变化显示出明显的外骨骼损伤。聚生体的微生物成员对A. typus显示出显着的趋化特性。结果表明，微生物聚生体是一种潜在的杀寄生虫剂，可用于控制A。水产养殖池塘中的斑疹伤寒，从而有利于水产养殖业，特别是小规模养殖者。