Lalitha, N.; Patil, P.K.; Rajesh, R., and Muralidhar, M., 2019. Usage of Pleurotus ostreatus for degradation of oxytetracycline in varying water salinities in brackishwater aquaculture system. In: Jithendran, K.P.; Saraswathy, R.; Balasubramanian, C.P.; Kumaraguru Vasagam, K.P.; Jayasankar, V.; Raghavan, R.; Alavandi, S.V., and Vijayan, K.K. (eds.), BRAQCON 2019: World Brackishwater Aquaculture Conference. Journal of Coastal Research, Special Issue No. 86, pp. 138-141. Coconut Creek (Florida), ISSN 0749-0208.

The oxytetracycline is being used in aquaculture industry as a broad spectrum antimicrobial agent with bacteriostatic property. Unregulated and indiscriminate usage of antibiotics leads to their buildup in the environment. Physical and chemical methods to remediate or remove these antibiotics are ineffective. The present study aims at the mycotic bioremediation of the oxytetracycline by Pleurotus ostreatus. It was cultured in the potato dextrose broth for 7 to 14 days and used in the experiment with fungal load of 10⁴ CFU ml^-l. In vitro soil based lab study was performed in triplicate at four different salinities 1, 15, 30 and 45 ppt, with three different concentrations of oxytetraycline (50, 150 and 250 mg L^-1), and treated with P. ostreatus. The suspended water samples were collected at periodic intervals of 2, 7 and 14 days after treatment and estimated for antibiotic in treatment and control. It was found that the P. ostreatus significantly (p ≤0.05) degraded the antibiotic at all salinities. The reduction of drug ranged from 58-76% (2 days), 45-78% (7 days) & 36-62% (14 days) at 1ppt, 32-34% (2 days), 58-71% (7 days) & 48-80% (14 days) at 15 ppt, 52-73% (2 days), 27- 61% (7 days) & 44-62% (14 days) at 30 ppt, and 32-68% (2 days), 44-66% (7 days) & 44-64% (14 days) at 45 ppt compared to the control.