*Correspondence: phamthithuha@tdtu.edu.vn; +84933092584 (Received: 10 April 2019; accepted: 08 August 2019) Citaton: Chau Thanh Truc, Pham Thi Thu Ha, Nguyen Thi Ngoc Tram and Do Thi Duyen, Evaluaton of Enzyme Protease Actvity and Inhibiton Efect on Pyricularia grisea with the Leaf Extract of Commela communis L., J Pure Appl Microbiol., 2019; 13(3): 1389-1396. htps://doi.org/10.22207/JPAM.13.3.09 © The Author(s) 2019. Open Access. This artcle is distributed under the terms of the Creatve Commons Atributon 4.0 Internatonal License which permits unrestricted use, sharing, distributon, and reproducton in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creatve Commons license, and indicate if changes were made. Truc et al. J Pure Appl Microbiol, 13(3), 1389-1396 | September 2019 Artcle 5623 | htps://doi.org/10.22207/JPAM.13.3.09 Print ISSN: 0973-7510; E-ISSN: 2581-690X ReseARCh ARtiCle OPeN ACCess www.microbiologyjournal.org 1389 Journal of Pure and Applied Microbiology Evaluaton of Enzyme Protease Actvity and Inhibiton Efect on Pyricularia grisea with the Leaf Extract of Commela communis l. Chau Thanh Truc, Pham Thi Thu Ha* , Nguyen Thi Ngoc Tram and Do Thi Duyen Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam. Abstract Rice blast is a dangerous disease that causes major damage to rice productvity worldwide. The purpose of this report is to examine the protease actvity of Pyricularia grisea and the efects of Commelina communis L. (common name “day fower”) extract on mycelial growth. The result showed that three isolates were collected from wild rice (Oryza rufpogon) based on a designaton of new internatonal standard and namely as U43-i4-k024-z05-ta532 (isolate 1); U12-i0-k101-z05-ta102 (isolate 2) and U43-i4-k141-z15-ta522 (isolate 3). Partcularly, the third isolate showed the highest protease enzyme actvity of 30.11 U/ml, followed by isolate 1 (20.27 U/ml) and isolate 2 (12.81 U/ml). The new fungi isolated from wild rice may be important methods to control detrimental diseases infestng cultvated rice. The result showed methanol extract from the day fower inhibitons on P.grisea. Besides protease actvity, fungi inhibiton was also afected. The protease actvity was low; the mycelial growth inhibiton was high (IC 50 = 2.35mg/mL at Isolate 2). Plant extracts from the day fower saved money and were environmentally friendly. So the implementaton of this substance is very essental. Keywords: Protease actvity, Pyricularia grisea, crude extract, antfungal actvity, mycelial growth.