Determination of plant growth promoting properties and bioremediation potentials of Bacillus mycoides Flügge and B. thuringiensis Berliner

Abstract

Industrial activities destroying natural resources for decades have been one of the most significant factors in environmental destruction. As a result of industrialization, environmental pollutants became one of the biggest threats for the biosphere. Heavy metals, one of these environmental pollutants, have become a significant health threat for organisms by forming metal accumulations in water and soil. In addition to the existing ones, most researchers believe that there is a great need for alternative biological processes to be used in the control of heavy metal pollution. Bioremediation is the process of removing various toxic pollutants, such as heavy metals from the environment, especially with the help of fungal and bacterial microorganisms, sometimes plants and earthworms. The use of bacteria in the bioremediation process is prevalent. In this study, the metal tolerance and plant growth-promoting properties of Bacillus mycoides and Bacillus thuringiensis isolated from the root soil of and orchid plant were investigated. The abilities of both bacteria to tolerate copper, lead, iron, silver, and zinc were tested in addition to and their indole acetic acid production (IAA), siderophore production, phosphate solubility and Aminocyclopropane-1-Carboxylate-deaminase (ACC-deaminase) activity were determined. The two isolates exhibited a high level of tolerance towards different pH levels, temperature ranges and metal concentrations. The results showed that B. mycoides and B. thuringiensis isolates can be used as bioremidant agents in metal-contaminated soils and also as biological fertilizers due to their plant growth-promoting properties.