Isolation of calcite precipitation bacteria to improve the strength of concrete

In this study, the calcite precipitation bacteria were investigated. Bacterial strains were isolated from cement samples and were tested for urease activities, potential to form endospore and calcite precipitation. The results showed that four candidates were isolated with high urease activities and calcite precipitation. | TRƯỜNG ĐẠI HỌC SƯ PHẠM TP HỒ CHÍ MINH TẠP CHÍ KHOA HỌC HO CHI MINH CITY UNIVERSITY OF EDUCATION JOURNAL OF SCIENCE KHOA HỌC TỰ NHIÊN VÀ CÔNG NGHỆ NATURAL SCIENCES AND TECHNOLOGY ISSN: 1859-3100 Tập 14, Số 9 (2017): 143-151 Vol. 14, No. 9 (2017): 143-151 Email: tapchikhoahoc@; Website: ISOLATION OF CALCITE PRECIPITATION BACTERIA TO IMPROVE THE STRENGTH OF CONCRETE Le Quynh Loan1, Nguyen Luong Hieu Hoa2, Tran Thi My Ngoc1, Duong Thi Phung Cac3, Nguyen Hoang Dung1,2* 1 2 Institute of Tropical Biology - VAST NTT Hitech Institute, Nguyen Tat Thanh University 3 Biotechnology Center of Ho Chi Minh City Received: 17/8/2017; Revised: 25/8/2017; Accepted: 23/9/2017 ABSTRACT Concretes are the second most consumed material on earth. However, it is susceptible to micro crack formation and has pores in it. The repairing cracks in concrete require high cost and labor and traditional repair system are chemical based, expensive and lead to environmental and health hazards. In this study, the calcite precipitation bacteria were investigated. Bacterial strains were isolated from cement samples and were tested for urease activities, potential to form endospore and calcite precipitation. The results showed that four candidates were isolated with high urease activities and calcite precipitation. Among them, the bacterial isolate N1 could precipitate g CaCO3 per liter. By using 16S rDNA sequencing, this strain was identified as Bacillus thuringiensis. The ability of this strain to tolerate the extreme environment of cement, it could be used in remediating the cracks and fissures in various building or concrete structure. Keywords: calcite precipitation, bacteria, concrete, isolation. TÓM TẮT Phân lập vi khuẩn có khả năng tạo kết tủa Calcite hướng đến mục đích tăng độ bền của bê tông Bê tông là vật liệu được tiêu thụ nhiều thứ hai trên thế giới. Tuy nhiên, theo thời gian sử dụng thì vật liệu này lại dễ hình thành các vết nứt và các lỗ li .