title: A Novel Phytase Derived from an Acidic Peat-Soil Microbiome Showing High Stability under Acidic Plus Pepsin Conditions.
abstract: Four novel phytases of the histidine acid phosphatase family were identified in two publicly available metagenomic datasets of an acidic peat-soil microbiome in northeastern Bavaria, Germany. These enzymes have low similarity to all the reported phytases. They were overexpressed in Escherichia coli and purified. Catalytic efficacy in simulated gastric fluid was measured and compared among the four candidates. The phytase named rPhyPt4 was selected for its high activity. It is the first phytase identified from unculturable Acidobacteria. The phytase showed a longer half-life than all the gastric-stable phytases that have been reported to date, suggesting a strong resistance to low pH and pepsin. A wide pH profile was observed between pH 1.5 and 5.0. At the optimum pH (2.5) the activity was 2,790 μmol/min/mg at the physiological temperature of 37°C and 3,989 μmol/min/mg at the optimum temperature of 60°C. Due to the competent activity level as well as the high gastric stability, the phytase could be a potential candidate for practical use in livestock and poultry feeding.
authors.affiliation: Soil and Fertilizer Institute, Sichuan Academy of Agricultural Sciences, and Scientific Observing and Experimental Station of Agro-Microbial Resource and Utilization in Southwest China, Ministry of Agriculture, Chengdu, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Tan
authors.forename: Xiang
authors.initials: X
authors.lastname: Wu
authors.forename: Liyuan
authors.initials: L
authors.lastname: Xie
authors.forename: Zhongqian
authors.initials: Z
authors.lastname: Huang
authors.forename: Weihong
authors.initials: W
authors.lastname: Peng
authors.forename: Bingcheng
authors.initials: B
authors.lastname: Gan
mesh_terms: D010832:6-Phytase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D061271:Acidobacteria / Q000201:enzymology / Q000235:genetics; D001671:Biochemistry; D004795:Enzyme Stability; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005750:Gastric Juice / Q000201:enzymology; D005765:Gastrointestinal Agents; D015870:Gene Expression; D005858:Germany; D006863:Hydrogen-Ion Concentration; D054892:Metagenome; D056186:Metagenomics; D010434:Pepsin A / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D017385:Sequence Homology; D012987:Soil; D012988:Soil Microbiology; D013696:Temperature
chemical_list: D005765:Gastrointestinal Agents; D011994:Recombinant Proteins; D012987:Soil; D010832:6-Phytase; D010434:Pepsin A