Department of Microbiology, University of Delhi South Campus, New Delhi 110021, India.
Antonie Van Leeuwenhoek. 2011 Jan;99(1):51-5. doi: 10.1007/s10482-010-9498-1. Epub 2010 Aug 22.
Among several yeasts isolated from dried flowers of Woodfordia fruticosa, Pichia anomala produced a high titre of cell-bound phytase. The optimization of fermentation variables led to formulation of media and selection of cultural variables that supported enhanced phytase production. The enzyme productivity was very high in fed batch fermentation in air-lift fermentor as compared to that in stirred tank fermentor. Amelioration in the cell-bound phytase activity was observed when yeast cells were permeabilized with Triton-X-100. The enzyme is thermostable and acid stable with broad substrate specificity, the characteristics that are desirable for enzymes to be used in the animal feed industry. The phytase-encoding gene was cloned and sequenced. The 3D structure of the enzyme was proposed by comparative modeling using phytase of Debaryomyces occidentalis (50% sequence identity) as template. When broiler chicks, and fresh water and marine fishes were fed with the feed supplemented with yeast biomass containing phytase, improvement in growth and phosphorus retention, and decrease in the excretion of phosphorus in the faeces were recorded. The cell-bound phytase of P. anomala could effectively dephytinize wheat flour and soymilk.
从干燥的文殊兰花朵中分离出的几种酵母中，异常毕赤酵母产生了高浓度的细胞结合植酸酶。通过对发酵变量的优化，我们制定了培养基配方，并选择了有利于提高植酸酶产量的培养变量。与搅拌釜发酵罐相比，在气升式发酵罐中的分批补料发酵中，酶的生产力非常高。当用 Triton-X-100 使酵母细胞透化时，观察到细胞结合植酸酶活性得到改善。该酶具有热稳定性和酸稳定性，以及广泛的底物特异性，这些特性是在动物饲料工业中使用酶所必需的。克隆并测序了编码该酶的基因。使用 Debaryomyces occidentalis 的植酸酶（50%序列同一性）作为模板，通过比较建模提出了该酶的 3D 结构。当向肉鸡、淡水鱼和海水鱼投喂添加了含有植酸酶的酵母生物质的饲料时，观察到生长和磷保留得到改善，粪便中磷的排泄减少。异常毕赤酵母的细胞结合植酸酶可以有效地使小麦粉和豆浆脱磷。
