A reusable immobilized microbial composition is designed to estimate the biochemical oxygen demand in industrial wastewater streams. The formulated microbial composition comprises a synergistic mixture of the bacterial strains of Enterobacter cloacae (ATCC no. 29893), Citrobacter amalonaticus (ATCC no. 25406), Pseudomonas aeruginosa (ATCC no. 49622), Yersinia enterocolitica (ATCC no. 27739), Klebsiella oxytoca (ATCC no. 15764), Enterobacter sakazakii (ATCC no. 12868) and Serratia liquefaciens (ATCC no. 25641). The consortium is immobilized by using 2% sodium alginate and 0.15 M calcium chloride to form beads. The said beads are tested as a microbial seeding material for BOD analysis using glucose–glutamic Acid (GGA) as a reference standard. The obtained BOD values were comparable with the values obtained by using sewage as the seeding material. Simultaneously the beads were tested on several synthetic samples as well as industrial effluents. The formulated microbial beads are a ready to use as well as reusable seeding material in BOD analysis. The said beads can be reused up to 5 times with the same efficacy.