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Phytotechnology with Biomass Production
stimulated the phytoremediation of soil contaminated by trace elements and
organics: oil, polyaromatic hydrocarbons, polychlorinated biphenyls, organochlorine, nitroaromatic, and organophosphate compounds (Guo & Chi, 2014;
Kidd et al., 2017; Muratova et al., 2003b). Through the inoculation of Populus
euphratica by PGPR strain Phyllobacterium sp. C65, which produced auxin,
assisted Populus euphratica to extract Zn more efficiently (Zhu et al., 2015).
7.2 Impact of PGPB Isolated from Contaminated
Soil to Phytoremediation with Miscanthus
In order to increase the biomass harvest of Miscanthus while growing in contaminated soils (Ben Fradj et al., 2020; Nsanganwimana et al., 2014; PachecoTorgal & Jalali, 2011), two main approaches can be used:
• soil treatment by different amendments such as fertilizers, sludge,
biosolids, citric acid, Ethylenediamine tetraacedic acid (EDTA), and
fungi (Antonkiewicz et al., 2019; Damodaran et al., 2013; Han et al.,
2018; Hu et al., 2018; Alasmary, 2020);
• plant rhizome treatment by co-composting, plant growth regulators,
and microorganisms (Khan et al., 2017; Leech et al., 2020; Nebeská
et al., 2019).
The effectiveness of PGPB in the phytoremediation of metal contaminated
soils can be explained by their ability to facilitate the adaptation of host plants
to suboptimal soil conditions during stress state; promote plant growth; vary
the bioavailability; relieve phytotoxicity in soil by producing amino acids,
proteins, and antibiotics; and increase contaminant translocation within the
plant (Oves et al., 2013). Also, PGPB can reduce the metals harmful effect by
reduction, oxidation, methylation or de-methylation, compartmentalization,
and conversion to a less toxic state (Hassan et al., 2017). Zeng et al. (2020)
investigated the positive role of extracellular polymeric substances produced
by Bacillus sp. S3 to detoxify different metals. Ndeddy Aka and Babalola (2016)
showed that inoculation of soil by PGPB: Pseudomonas aeruginosa KP717554,
Alcaligenes faecalis KP717561, and Bacillus subtilis KP717559 increased the
amount of soluble Ni, Cd, and Cr in the soil by 51%, 50%, and 44%, respectively. Ma et al. (2015) researched the phytostabilization potential of PGPB in
relation to metal contaminated soils: inoculation by Pseudomonas sp. A3R3
improved plant biomass production while Psychrobacter sp. SRS8 inoculation increased the accumulation of metals by plants. PGPB and Miscanthus sp.
association in the metal contaminated soil was researched by Babu et al.
(2015) and Schmidt et al. (2018). An endophytic PGPB Pseudomonas koreensis
was explored for enhancing the production of Miscanthus sinensis growing in
soil contaminated by As, Cd, Cu, Pb, and Zn (Babu et al., 2015).