Assessment of in vitro Multiplication of Lemna minor in the Presence of Phenol: Plant/Bacteria System for Potential Bioremediation – Part I

Abstract

The aim of this work was to examine the multiplication of the common duckweed (Lemna minor), an aquatic plant species widespread in European stagnant waters, in two different media (Murashige -Skoog and Hoagland) with and without phenol supplementation. In order to quantify plant multiplication we have used relative growth rate and tolerance indices on both tested media and at five phenol concentrations (10, 15, 20, 30 and 100 mg/L). Furthermore, we examined the possibility of phenol removal from aqueous media containing different phenol concentrations, by using plant/bacteria system consisting of the duckweed and its naturally occurring microbial populations. After 7 days, number of newly formed fronds was approximately four times higher than at the beginning of the experiment on both tested media. The most important result in this study was removal of 70% of phenol from the highest initial concentration of 100 mg/L, in mixed cultures of duckweed and bacteria. By comparison, aseptic duckweed cultures removed approximately 50% of phenol at the same initial concentration. Our duckweed specimen showed a fast reproduction rate, high tolerance to phenol and a possible cooperation with rhizosphere-associated bacteria. All of these traits can be ultimately utilized for bioremediation purposes.

Phenol Removal Capacity of the Common Duckweed (Lemna minor L.) and Six Phenol-Resistant Bacterial Strains From Its Rhizosphere: In Vitro Evaluation at High Phenol Concentrations

“…Therefore, this study expands the list of phenol-degrading bacteria from the duckweed rhizosphere. Although the 4-AAP method applied in this study does not discriminate between phenolic compounds, exogenous and endogenous, according to our previous results, the amount of phenols synthesized by the plants and the microbial community under similar experimental conditions was negligible [49]. Therefore, it is our belief that the interference with the measurement is minimal.…”

“…The excess bleach was washed off with sterile distilled water three times. Plants (2-4 fronds) were placed on a Murashige-Skoog (MS) medium without agar (liquid medium) according to the previously applied protocol [49]. Plants were grown at 24 ± 2 • C (under fluorescent light of 40 µmoL m −2 s −1 with 16 h light/8 h dark photoperiod).…”

“…Bacterial cultures were grown and maintained on a Luria-Bertani (LB) medium, prepared according to the previously applied protocol [49,51]. Bacterial strains used in this experiment were as follows: strain 9-Klebsiella oxytoca A6-104/2, MF526910; strain 11-Lelliottia sp.…”

A Review: Disinfectant, Antiseptic, and Its Use for Infection

“…Corrosive to metal, activity decreases when there is an organic material (Russell, 1990) lammable, pungent, toxic (absorbed by the entire route), (Radulovic et al, 2018) leaving residue on the surface, inactivated by hard water, reduced activity by nonionic detergents. (Mcdonnell, 2007).…”

Antioxidative Responses of Duckweed (Lemna minor L.) to Phenol and Rhizosphere-Associated Bacterial Strain Hafnia paralvei C32-106/3

“…In duckweeds, favorable modulation of antioxidative response is reported to be correlated with plant-growth-promoting abilities of bacteria [ 15 , 16 ]. Our previous studies on duckweeds also showed a promotive effect of the natural bacterial community in rhizosphere, most prominently on the plants’ multiplication [ 17 , 18 , 19 ]. However, information regarding the effect of rhizosphere-associated bacteria on the oxidative stress response of aquatic plants, especially under the conditions of abiotic stress such as phenol pollution, is still lacking [ 15 , 16 ].…”