TAF PUBLISHING

Therefore, this study aimed to isolate and screen PNSB from shrimp ponds with their ability to reduce phosphate in water from shrimp cultivation. A total of 83 PNSB strains were isolated from water and sediment samples collected from various 15 shrimp ponds located in Phang-nga and Songkhla provinces. For primary screening, there were 42 strains (51%) that grew well (OD660> 1.0) in glutamate-acetate broth supplemented with 1.5% (w/v) NaCl, under conditions of microaerobic-light and aerobic-dark. However, in secondary screening, only two strains (W12 and W48) could grow in sterile rearing water collected from shrimp ponds. They were selected for tertiary screening to investigate their ability to remove phosphate in sterile rearing water under both incubating conditions. Both PNSB strains produced no significant differences for phosphate removal efficiency (> 50%) with the exception under microaerobic-light conditions as strain W12 roughly reduced 46% phosphate. Of these, 2 strains could be used as inoculants to remove phosphate from rearing water in shrimp ponds. One of the key environmental concerns about shrimp cultivation is the discharge of rearing water with high levels of nutrients, especially phosphate, into waterways, resulting in eutrophication. To solve this problem, biological treatment is well-recognized, and the use of purple non-sulfur bacteria (PNSB) is one of the attractive alternative choices because of their high removal efficiency in wastewater treatment with various metabolic growth conditions.