Document Type : ترویجی
Authors
1
Ph.D. graduate, Soil fertility and biotechnology management, Department of Soil Sciences, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran.
2
Professor, Department of Soil Sciences, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran.
3
Professor, Department of Microbiology, Shiraz Branch, Islamic Azad University, Shiraz, Iran.
4
Assistant Prof., Department of Biology, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran.
Abstract
Microbial urease has specific applications in biotechnology, agriculture, medicine, construction and geotechnical engineering. MICP technology is an ecological process based on microbial urease activity that has recently been used for soil stabilization. Due to its catabolic ability and high survival, Bacillus is considered as a suitable candidate for use in the biocementation process. The aim of this study was isolating and identifying Bacillus with MICP potential from various ecosystems of Iran.200 environmental samples were collected from the ecosystems of Iran and were analyzed by microbiological and molecular methods including PCR amplification and sequence analysis of gyrA and 16S rRNA genes in order to isolate and identify bacilli. Growth in presence of urea, salinity, pH and different temperatures, SEM, XRD and wind tunnel analysis were used to determine the ability of isolates to produce biocement. A total of 12 isolates(6%) were identified as urease-positive bacilli belonging to 4 different species, including 4 isolates of Bacillus paramycoides(33.33%), 3 isolates of Bacillus paralicheniformis(25%), and 3 isolates of Bacillus velezensis. isolate(25%) and Bacillus Pasteuri 2 were isolated(16.66%). The optimal conditions for MICP by isolates are 30°C, pH 9 and salinity 6%. After MICP, the ratio of soil loss in the flow rate of 95 km/h showed a 100-fold decrease. In conclusion, the results showed that bacilli have the potential ability to adapt to harsh environmental conditions. Also, by using MICP-producing bacilli on the soil surface, we can have a significant effect in reducing soil losses due to erosion.
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