Characterization of Heavy Metal Tolerant and Plant Growth-Promoting Rhizobacteria Isolated from Soil Contaminated with Heavy Metal and Diesel

Abstract

In order to enhance rhizoremediation performance, which remediates contaminated soils using the interactions between plants and microorganisms in rhizosphere, it is required to develop effective microbial resources that simultaneously degrade contaminants and promote plant growth. In this study, heavy metal-resistant rhizobacteria, which had been cultivated in soils contaminated with heavy metals (copper, cadmium, and lead) and diesel were isolated from rhizospheres of maize and tall fescue. After that, the isolates were qualitatively evaluated for plant growth promoting (PGP) activities, heavy metal tolerance, and diesel degradability. As a result, six strains with heavy metal tolerance, PGP activities, and diesel degradability were isolated. Strains CuM5 and CdM2 were isolated from the rhizosphere soils of maize, and were identified as belonging to the genus Cupriavidus. From the rhizosphere soils of tall fescue, strains CuT6, CdT2, CdT5, and PbT3 were isolated and were identified as Fulvimonas soli, Cupriavidus sp., Novosphingobium sp., and Bacillus sp., respectively. Cupriavidus sp. CuM5 and CdM2 showed a low heavy metal tolerance and diesel degradability, but exhibited an excellent PGP ability. Among the six isolates, Cupriavidus sp. CdT2 and Bacillus sp. PbT3 showed the best diesel degradability. Additionally, Bacillus sp. PbT3 also exhibited excellent heavy metal tolerance and PGP abilities. These results indicate that the isolates can be used as promising microbial resources to promote plant growth and restore soils with contaminated heavy metals and diesel.

Metal-tolerant and siderophore producing Pseudomonas fluorescence and Trichoderma spp. improved the growth, biochemical features and yield attributes of chickpea by lowering Cd uptake

“…Like the current observation, soil isolates recovered from metal polluted soil have been reported to displayed a dissimilar heavy metal tolerance profile 24 . Similarly, PGPR strain like Bacillus sp., Cupriavidus sp., Cupriavidus sp., Fulvimonas soli and Novosphingobium sp., isolated from rhizosphere soil tolerated heavy metal concentrations 43 . In yet another study, Fahsi and co-workers 44 reported that Enterobacter hormaechei J-146 could withstand up to 1.5 mg L −1 of Cu/Cd, while B. halotolerans J-143 could tolerated up to 1.5 mg L −1 of Ni.…”

Effect of Novosphingobium sp. CuT1 inoculation on the rhizoremediation of heavy metal- and diesel-contaminated soil planted with tall fescue

“…To evaluate the PGP properties of strain CuT1, indole-3-acetic acid (IAA), siderophore, and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase production were investigated as described by Lee et al (2021a).…”

“…The diesel concentration extracted from the supernatant was measured via a gas chromatography (GC 6980N system, Agilent Technologies, CA, USA) equipped with a ame ionization detector (FID; Agilent Technologies) and an HP-5 capillary column (30 m × 0.320 mm × 0.25 µm, Agilent Technologies). All procedures were performed as described in our previous report (Lee et al, 2021a). The diesel removal e ciency was calculated as a percentage by comparing the initial diesel concentration with the residual diesel concentration after two weeks.…”

Diversity of prokaryotic communities associated with sponges in Vietnam and their secondary metabolite biosynthetic potential

“…The structures of these compounds were elucidated by the examination of their ESI-MS and NMR ( 1 H NMR, 13 C NMR, HMBC, HSQC) spectra (Figures S1-S20) and comparison with reported data. The compounds were identified as cyclo(L-Pro-L-Tyr) (1) (Wattana-Amorn et al, 2016), macrolactin A (2) (Lee et al, 2004;Romero-Tabarez et al, 2006), macrolactin H (3) (Nagao et al, 2001), and 15,17-epoxy-16-hydroxy macrolactin A (4) (Mondol et al, 2011).…”

“…Although numerous macrolide compounds have been isolated and identified from sponges and their symbionts (Karpiński, 2019), this is the first study to report the isolation of macrolactins from sponge-associated bacteria. Macrolactin A (2) has been frequently isolated from different bacteria (Nagao et al, 2001;Lee et al, 2004;Romero-Tabarez et al, 2006;Lu et al, 2008;Kim et al, 2011;Tareq et al, 2013;Li et al, 2016a), whereas macrolactin H (3) and 15, 17-epoxy-16-hydroxy macrolactin A (4) have been rarely isolated (Nagao et al, 2001;Mondol et al, 2011). Previous bioassays revealed that macrolactin A exhibited antimicrobial activity against Gram-negative bacteria (i.e., E. coli), Gram-positive bacteria (i.e., S. (Nagao et al, 2001;Lee et al, 2004;Romero-Tabarez et al, 2006;Lu et al, 2008;Kim et al, 2011;Tareq et al, 2013;Li et al, 2016a).…”