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Potential of Napier grass with cadmium-resistant bacterial inoculation on cadmium phytoremediation and its possibility to use as biomass fuel

Wiangkham, Nongnuch, Prapagdee, Benjaphorn
Chemosphere 2018 v.201 pp. 511-518
Arthrobacter, Cenchrus purpureus, Micrococcus, air, bacteria, bioaccumulation factor, biofuels, biomass, cadmium, combustion, phytoremediation, soil
This work mainly aims to explore the potential of synergistic use of cadmium-resistant bacteria and Napier grass to promote cadmium phytoremediation and the possibility of using the harvested Napier grass for biomass fuel. A pot experiment was carried out by transplanting Napier grass with and without bacterial inoculation in cadmium contaminated soil for 6 months. The results found that Micrococcus sp. significantly promoted the shoot biomass of Napier grass but not the root biomass. Micrococcus sp. and Arthrobacter sp. stimulated cadmium accumulation in the root and the shoot. Cadmium was retained more in the root than the shoot at all plantation periods. The maximum cadmium content in a whole plant was found in plants inoculated with Micrococcus sp. at six months. The values of phytoextraction coefficient and bioaccumulation factor in plants with bacterial inoculation were higher than those in the uninoculated control. Translocation factor was very low. Napier grass could be considered as a candidate plant for cadmium phytostabilization. The calorific value of Napier grass transplanted in cadmium-contaminated soil was similar to that in uncontaminated soil, but cadmium was still retained in the ash and some was emitted into the air. In conclusion, these cadmium-resistant bacteria enhanced the performance of Napier grass on cadmium phytoremediation. The harvested Napier grass can be used for biomass fuel under controlled ash and air emission from the combustion process.