Production of high activity thermostable phytase from thermotolerant Aspergillus niger in solid state fermentation
作者:T N Mandviwala、J M Khire
DOI:10.1038/sj.jim.2900811
日期:2000.4.1
The thermotolerant fungus, Aspergillus niger NCIM 563, was used for production of extracellular phytase on agricultural residues: wheat bran, mustard cake, cowpea meal, groundnut cake, coconut cake, cotton cake and black bean flour in solid state fermentation (SSF). Maximum enzyme activity (108 U g−1 dry mouldy bran, DMB) was obtained with cowpea meal. During the fermentation phytic acid was hydrolysed completely with a corresponding increase in biomass and phytase activity within 7 days. Phosphate in the form of KH2PO4 (10 mg per 100 g of agriculture residue) increased phytase activity. Among various surfactants added to SSF, Trition X-100 (0.5%) exhibited a 30% increase in phytase activity. The optimum pH and temperature of the crude enzyme were 5.0 and 50°C respectively. Phytase activity (86%) was retained in buffer of pH 3.5 for 24 h. The enzyme retained 75% of its activity on incubation at 55°C for 1 h. In the presence of 1 mM K+ and Zn2+, 95% and 55% of the activity were retained. Scanning electron microscopy showed a high density growth of fungal mycelia on wheat bran particles during SSF. Journal of Industrial Microbiology & Biotechnology (2000) 24, 237–243.
耐热真菌黑曲霉 NCIM 563 用于在固态发酵 (SSF) 中利用农业残留物生产胞外植酸酶:麦麸、芥菜饼、豇豆粉、花生饼、椰子饼、棉饼和黑豆粉。豇豆粉获得最大酶活性(108 U g−1 干发霉麸皮,DMB)。在发酵过程中,植酸完全水解,7天内生物量和植酸酶活性相应增加。 KH2PO4 形式的磷酸盐(每 100 克农业残留物含 10 毫克)可提高植酸酶活性。在添加到 SSF 中的各种表面活性剂中,Trition X-100 (0.5%) 的植酸酶活性提高了 30%。粗酶的最适pH为5.0,最适温度为50℃。植酸酶活性(86%)在pH 3.5的缓冲液中保留24小时。在 55°C 下孵育 1 小时后,该酶保留了 75% 的活性。在 1mM K+ 和 Zn2+ 存在下,保留了 95% 和 55% 的活性。扫描电子显微镜显示,SSF 期间麦麸颗粒上真菌菌丝体高密度生长。工业微生物学与生物技术杂志 (2000) 24, 237–243。