SELECTION AND CHARACTERIZATION OF MULTIFUNCTIONAL MICROBIAL STRAINS FOR THE DEVELOPMENT OF PHYTOREMEDIATION STRATEGIES

Abstract

Characterization of PGPM microorganisms is an important step in selecting strains as bioinoculants. In this study, the PGPM properties of 98 isolates recovered from soil, rhizosphere, and plant tissues grown in oil-contaminated soil were assessed. Of the 98 isolates tested, 21.4% exhibited proteolytic activity, 24.4% exhibited amylolytic activity, and 9.2% exhibited cellulolytic activity on agar media with specific substrates. After the initial screening, 20 isolates (N9, N11, MSM12, MSM3, MSM20, MSM21, MSM25, MSM20, V16, L5-2, L5-5, L5-6, L10-2, L10-6, L10-12, L10-10, KP5, KB9, KP10 and C10) demonstrating high double or triple hydrolytic activity were selected. The stepwise screening methodology allowed the selection of strains demonstrating more than one or several properties with PGPR properties that ensure plant growth such as: phytohormone production, nitrogen fixation, IAA secretion, production of iron chelating compounds, phosphate solubility and synthesizing hydrolytic enzymes. Therefore, multifunctional strains with PGPR properties can be used as the most promising inoculants to improve the efficiency of phytoremediation of oil-contaminated soils.

Keywords: IAA, bacteria that promote plant growth, siderophores, phytohormones, phosphates, nitrogen fixation, protease, cellulase, amylase.