Phytase activity of phytase-producing bacteria isolated from mangrove sediment

Abstract

Through the role of phytase, some soil bacteria can mineralize insoluble organic P such as phytate (myoinositol hexakisphosphate). Phytase is a secreted enzyme possessing the ability to hydrolyze phytate into phosphate esters and inorganic P for plants absorption. This study aimed to isolate phytase-producing bacteria from mangrove sediment and examine the influence of nutrients (source of carbon, nitrogen, phosphorus) and physical conditions (temperature, pH, NaCl tolerance) on maximum phytase production. The presence of phytase activity was determined by examining the individual colonies for the formation of a clear zone. Furthermore, the isolates were screened qualitatively and quantitatively using solid and liquid phytase screening medium (PSM) containing sodium Phytate as substrates. The result showed that a total of 48 isolates have the potential to produce phytase with a production range of 1.11 - 14.83U/mL. The isolate F15 as Bacillus altitudinis was found to produce the highest phytase after 72 hours of incubation, was selected for further analysis. This strain resulted in optimal phytase levels at 35°C and a pH of 6.5 in physical parameters, tolerated 5% NaCl in the presence of lactose and tryptone, which served as carbon and nitrogen sources, respectively.