1.3.8 and 3.1.3.26) belong to families of histidine acid or alkaline phosphatases, which are capable of hydrolyzing phytic acid to myoinositol derivatives and inorganic phosphates (Oh et al., 2004). Phytases have been characterized from various microorganisms, in particular filamentous fungi. Phytase from Aspergillus niger is commercially available as a feed supplement (BASF). Supplementation of animal diets with microbial

learn more phytase reduces the need for phosphorus supplements and tends to increase the bioavailability of proteins and essential minerals, thus improving growth performance (Casey & Walsh, 2004). It also reduces the amount of phosphorus in animal manure, thereby helping decrease phosphorus pollution in the environment. Not many phytases have been exploited in the feed industry because of several factors including high manufacturing costs, poor stability, and low specific activity of the enzyme in the environment of desired applications (Pasamontes et al., 1997; Rodriguez et al., 2000; Wang et al.,

2007). Previously, phytases have been screened from various fungi in Thailand’s BIOTEC culture collection. Among these, A. niger BCC18081 and Aspergillus japonicus BCC18313 were shown to produce phytases that can function at pH 3 and 5.5 (Promdonkoy et al., 2009). Thus, these phytases potentially possess an ability to withstand and function efficiently in the acidic environment of animal stomach and in conditions similar to animal intestine. Subsequently, genes encoding these two phytases were cloned and expressed in Pichia pastoris KM71. The recombinant phytases, r-PhyA170 and r-PhyA86, were shown to be secreted selleck products efficiently into the culturing medium (Promdonkoy et al., 2009). Furthermore, these enzymes exhibited high thermostability, as approximately 70% of activity was retained after incubation at SPTLC1 70 °C for 60 min. Most importantly, in vitro digestibility tests suggested that the recombinant phytases were at least as efficient as the commercial phytase for hydrolyzing phytate present in animal feed and are therefore suitable sources of phytase supplementation. Cell-surface technology

allows target proteins to be anchored on the cell surface. The proteins expressed would therefore behave as extracellular-like proteins and be glycosylated. Initially, the cell-surface expression system was studied in filamentous phage infecting Escherichia coli, leading to the development of a phage display system (Ueda & Tanaka, 2000a, b). Cell-surface display in yeast was developed for its application in biofuels, biosensors, vaccine-delivery vehicles, and screening platforms. Many mannoproteins located on the yeast cell wall and linked to lipid bilayer by β-linked glucans have already been identified (Watari et al., 1994; Van der Vaart et al., 1995; Kondo & Ueda, 2004), for example agglutinins (AGα1 and Aga1), Flo1p, Cwp1p, Cwp2p, and Tip1p.