Suresh S, Radha K V
J Environ Biol. 2016 Mar;37(2):253-9.
The present study deals with production of phytase from Rhizopus oligosporus MTCC 556 by solid state fermentation (SSF) using different (ADT27, IR20, PAIYUR1, KG, and RASI) rice bran varieties, in which ADT27 rice bran yield maximum of 6.2 U gds⁻¹ phytase. Statistical optimization was employed by Central Composite Design (CCD); the results showed that 3.0 g dextrose, 2.5 g ammonium nitrate, substrate size of 80 mesh, 10 mg calcium chloride was 116 hr at optimal for phytase production by SSF, with maximum of 23.14 U gds'. Phytase production improved by 4 fold (31.3 U/gds) due to chemical mutagenesis (mutant Rhizopus oligosporus MTCC 1116) in optimized media composition. Partially purified phytase showed approximately 90 kDa of molecular mass and was optimally active at 5.5 pH and 50°C temperature. Substrate specificity exhibited in sodium phytic acid and phytase activity was stimulated by Zn²⁺ and Ca²⁺.
本研究探讨了利用不同品种（ADT27、IR20、PAIYUR1、KG和RASI）的米糠通过固态发酵（SSF）从少孢根霉MTCC 556生产植酸酶，其中ADT27米糠的植酸酶产量最高，为6.2 U gds⁻¹。采用中心复合设计（CCD）进行统计优化；结果表明，对于通过固态发酵生产植酸酶而言，3.0 g葡萄糖、2.5 g硝酸铵、80目底物粒度、10 mg氯化钙，在116小时时最为适宜，最高产量为23.14 U gds⁻¹。在优化的培养基组成中，由于化学诱变（突变体少孢根霉MTCC 1116），植酸酶产量提高了4倍（31.3 U/gds）。部分纯化的植酸酶分子量约为90 kDa，在pH 5.5和温度50°C时具有最佳活性。底物特异性表现在植酸钠上，并且Zn²⁺和Ca²⁺可刺激植酸酶活性。
