Phytase widely exists in plants, fungi, yeast and bacteria, among which microbial phytase has been widely studied and developed because of its high activity and easy production, and Trichoderma phytase has a long history. During 1998, Anusuya et al. studied the degradation of calcium phosphate and phosphate stones by Trichoderma harzianum, Trichoderma viride and Trichoderma pasteureum, and compared them with Bacillus megaterium and Aspergillus awamori. The results showed that all three Trichoderma species contained two insoluble phosphates. In 1999, Altomare et al. found that Trichoderma harzianum strain T22 has the ability to dissolve insoluble or slightly soluble minerals, which can degrade dissolved metal oxides through chelation, promote the absorption of minerals by plants and increase the growth of plants. In the same year, n? Si M et al. compared the differences of phytase utilization between Aspergillus Niger (Aphy) and Trichoderma reesei (Tphy) in corn-soybean feed and barley-soybean feed. The comparative feeding experiment showed that the utilization ratio of phytase from Trichoderma reesei to phytate phosphorus in feed was higher than that from Aspergillus Niger and acid phosphatase. In 2005, Wang Shihua, Fujian Agriculture and Forestry University and so on. Trichoderma viride strain LH 374 was isolated and mutated by nitrosoguanidine. The optimum temperature is 55℃ and the optimum pH is 6.0. It has good thermal stability and acid resistance, and the average phytase yield can reach1580 u/g; Yang Contract of Shandong Academy of Sciences collected 244 soil samples from Shandong vegetable base, and Trichoderma isolated from them basically has phosphorus solubilizing activity, which can hydrolyze calcium phytate and calcium phosphate on agar plate to form a transparent hydrolysis circle. Juck Zhang et al. (20 12) inoculated 148 strains of Trichoderma into phytase-producing medium. After 3 days, it was observed that all strains produced hydrolysis circles. At the same time, the phytase activity of Trichoderma was detected by ferric chloride-sulfosalicylic acid method with phytic acid as substrate, which showed that phytase production was a universal property of Trichoderma.
In terms of gene, the gene sequence of Trichoderma harzianum phytase PhyA (AJ543399. 1) submitted by Rey et al. can be retrieved in GenBank and has homology with phytase such as Aspergillus. In addition, the recent patents of Trichoderma reesei phytase (patent US 75 1083 1, GenBank:GP287369. 1+0) have no homology with other phytases. A patent of Genentech International Limited (application number 20090246856) mentioned that an active phytase was purified from Trichoderma reesei ATCC 1363 1 and its DNA sequence was cloned. Its amino acid sequence is 4 1% ~ 49% homologous to phytase from other filamentous fungi, but the amino acid sequence in the active region is highly homologous to other filamentous fungi.
Bruce Lee et al. (20 10) investigated the phytase activity of 136 strains of Trichoderma preserved in the laboratory. The preliminary results showed that Trichoderma generally had phytase activity. According to the fact that the radius of transparent circle is obviously larger than the colony radius (radius difference ≥0.3cm), 36 strains with high phytase activity were screened out. Through the structural prediction and analysis of the cloned Trichoderma phytase, it is found that Trichoderma has a potential structure with higher thermal stability and catalytic activity than Aspergillus Niger phyA in the functional structural components that affect the two important enzymatic properties of phytase.