Ecology, Environment and Conservation Paper

INACTIVATION OF HARMFUL ALGAL BLOOMS IN FRESH WATER USING ALGICIDAL BACTERIA PSEUDOMONAS SP. FROM WASTEWATER TREATMENT PLANT

Mohammed Al-Sahari, Adel Al-Gheethi, Radin Maya Saphira Radin Mohamed and Nurina Fitriani

Abstract

The inactivation of harmful algae blooms (HABs) was investigated in the present study as a response for the algicidal bacterial cells. Moreover, the optimization of the inactivation process was conducted using response surface methodology (RSM). Four independent variables included algicidal bacteria dosage (10-100 mL L-1), pH (4-10), mixing speed (50-185 rpm), and hydraulic retention time (30-180 min). The inactivation rate was estimated based on the reduction in Chl-a while the inactivation mechanism was observed scanning electronic microscopy (SEM). The results revealed that the optimal inactivation (87.95%) was recorded with100 mL L-1 of bacterial supernatant, pH 4.51, 150 rpm and after 180 min. The results of SEM revealed that the algicidal bacteria inactivated HABs by destructing of the cell wall which led to a change of the spherical shape of HABs cells.