RESUMEN
The heavy metal resistant bacterium isolated from field soil and identified as Enterobacter sp. RZS5 tolerates a high concentration (100-2000 mM) of various heavy metal ions such as Mn2+, Ni2+, Zn2+, Cu2+, CO2+ and Fe2+ when grown in such environment and produces exopolysaccharides (EPS). Here, we have demonstrated EPS production by Enterobacter sp. RZS5 during 60 h of growth in yeast extract mannitol broth (YEMB). The yield increased by two fold after the addition of 60 M of Ca2+; 50 M of Fe2+ and 60 M of Mg2+ ions in YEMB, and the optimization of physico-chemical parameters. EPS was extracted with 30% (v/v) of isopropanol as against the commonly used 50% (v/v) isopropanol method. EPS-rich broth promoted seed germination, shoot height, root length, number of leaves and chlorophyll content of wheat (Triticum aestivum) and peanut (Arachis hypogaea) seeds. The higher colony-forming unit of Enterobacter sp. in soil inoculated with EPS rich broth of Enterobacter sp. indicated the root colonizing potential and rhizosphere competence of the isolate. The FTIR spectra of the EPS extract confirmed the presence of the functional group characteristics of EPS known to exhibit a high binding affinity towards certain metal ions. This overall growth and vigour in plants along with the effective root colonization, reflected the potential of the isolate as an efficient bio-inoculant in bioremediation.
Asunto(s)
Arachis/efectos de los fármacos , Arachis/crecimiento & desarrollo , Arachis/metabolismo , Biodegradación Ambiental/efectos de los fármacos , Clorofila/metabolismo , Enterobacter/efectos de los fármacos , Enterobacter/metabolismo , Enterobacter/fisiología , Germinación/efectos de los fármacos , Interacciones Huésped-Patógeno , Metales Pesados/metabolismo , Metales Pesados/farmacología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/microbiología , Brotes de la Planta/efectos de los fármacos , Brotes de la Planta/crecimiento & desarrollo , Brotes de la Planta/metabolismo , Polisacáridos Bacterianos/biosíntesis , Polisacáridos Bacterianos/farmacología , Semillas/efectos de los fármacos , Semillas/crecimiento & desarrollo , Semillas/metabolismo , Suelo/química , Microbiología del Suelo , Espectroscopía Infrarroja por Transformada de Fourier , Triticum/efectos de los fármacos , Triticum/crecimiento & desarrolloRESUMEN
Pseudomonas aeruginosa isolated from banana field rhizosphere produced different antifungal metabolites like bactriocin, hydrogen cyanide and siderophore. Bacteriocinogenic, siderophoregenic, and HCN rich broth of isolate inhibited the growth of phytopathogen like Aspergilus niger, Aspergilus flavus, Fusarium oxysporum and Alternaria alternata. The isolate exhibited more antifungal activity and comparatively low MIC vis-a-vis commonly used copper based systemic chemical fungicide;bil cop.