Preliminary optimization of solid-state phytase production by moderately halophilic Pseudomonas AP-MSU 2 isolated from fish intestine

Abstract

The production of extracelluar phytase by Pseudomonas AP-MSU 2 isolated from the estuarine fish Etroplus suretensis was investigated in solid-state fermentation. Screening of agroindustrial substrates revealed that cassava waste meal produced a higher amount of phytase. The most suitable nitrogen source to enhance phytase production was found to be sodium nitrate. Among various carbon sources tested, maximum production of phytase was registered in medium with added fructose. The effect of surfactants indicated that maximum phytase production was observed in medium supplemented with Tween 60. NaH2PO4 and ZnCl were found to be a suitable phosphate and metal ion source, respectively, for maximizing phytase production. The optimum sodium chloride concentration for high phytase production was found to be 3%. The optimum pH and temperature for phytase production were found to be 7 and 30°C, respectively. Statistical optimization using a Plackett-Burman design showed that fructose, sodium nitrate, NaCl, Tween 60 and zinc chloride were positive factors for phytase production, and that NaH2PO4 had a negative effect on phytase production.