Isolation and characterization of a biosurfactant-producing heavy metal resistant Rahnella sp. RM isolated from chromium-contaminated soil

Abstract

Objective of the study was to isolate heavy metal resistant bacteria from chromiumcontaminated subsurface soil and investigate biosurfactant production and heavy metal bioremediation. Based on 16S rRNA gene sequence and phylogenetic analysis, the isolate was identified as Rahnella sp. RM. The biosurfactant production by heavy metal resistant Rahnella sp. RM was optimized using Box-Behnken design (BBD). The maximum emulsification activity was obtained 66 % at 6 % soybean meal in pH 7.0 and 33.5 °C. The biosurfactant was characterized using Field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FT-IR) and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF). The highest metal removal rates using the biosurfactant were found 74.3, 72.5, and 70.1 %, respectively, at the 100 mg/L amended flasks at 48 h. This study indicated the biosurfactant from heavy metal resistant Rahnella sp. RM could be used as a potential tool to remediate the metals in contaminated environments.

Isolation and Identification of Biosurfactant Producing Chromate Resistant Bacteria Isolated From Chromium Contaminated Site.

“…The inability of TB5 to emulsify the oil indicated its failure to produce biosurfactant and hence, the hemolytic activity could be attributed to extracellular secretions. Similar findings were reported by Adamu et al, (2015) and Govarthanan et al, (2017). Results for oil spreading test (Table 1) of the kerosene oil revealed that strain TB9 and TB10 caused the spreading of the oil at the rate of 6 and 5 minutes with a diameter of 2.7 cm and 3.3 cm, respectively.…”

Characterization of hydrocarbon degrading bacteria at EPEA Station (38º 28’ S – 57º 41’ O) Atlantic coast

“…Although among halophilic bacteria, Halomonas sp. has been shown to utilize a wide range of readily available substrates as energy sources for its fast growth (Ali et al 2016) and is multi-metal resistant (Govarthanan et al 2017), to our knowledge there are few studies on PAH degrading Halomonas isolated from marine waters (Gasperotti et al 2015;Corti Monzón et al 2018;Izzo et al 2019;Govarthanan et al 2020). It is worth noting that H. meridiana and H. sulfidaeris strains retrieved from deep sea sediments were also previously reported as PAH degraders (Cui et al 2008;Yuan et al 2015).…”

Tailoring Next Generation Plant Growth Promoting Microorganisms as Versatile Tools beyond Soil Desalinization: A Road Map towards Field Application

“…Khan et al [110] report the potential of four bacterial strains Pseudomonas poae BA1, Acinetobacter bouvetii BP18, Bacillus thuringiensis BG3, and Stenotrophomonas rhizophila BG32 for the degradation of hydrocarbons by biosurfactants. Biosurfactants have been widely studied in the bioremediation of pollutants [111]. They are amphiphilic molecules containing polar (hydrophilic groups) and nonpolar (hydrophobic groups) groups and have surface or interface related properties [111].…”

“…Biosurfactants have been widely studied in the bioremediation of pollutants [111]. They are amphiphilic molecules containing polar (hydrophilic groups) and nonpolar (hydrophobic groups) groups and have surface or interface related properties [111]. They have several advantages: biodegradability, low toxicity, high surface activity, and high yield even under extreme environmental conditions [112].…”