PHYTOENERGY: energetic valorisation of phytoremediation derived biomass

There are presently more than 3 million contaminated sites all over EU, according to the EEA (report 25186 EN), with the contamination with heavy metals being of particular concern, as they are not degradable. Soil recovery is thus becoming an urgency and diverse approaches can be applied. From these, phytoremediation has shown to be an attractive low cost alternative as it promotes the establishment of a vegetation cover, stabilizing these degraded sites and allowing for the slow extraction of the contaminants. In spite that the fate of the harvested plants is a common complication for its implementation, it can also represent an opportunity for producing added value. This work intends to assess the possibility of the production of biodiesel resulting from the transterification of sunflower seed oil with bioethanol resulting from the processing of sunflower stems. Sunflower plants growing either in agricultural and metal contaminated soils were assessed and the quality of the successive energetic products was evaluated. Sunflower seeds were used for oil extraction, with observable extraction efficiencies of up to 20 ml oil/m 2 ; plant stems were used for bioethanol production with yields of up to 280 ml/m 2 ; finally, biodiesel was generated via transterification. The final biodiesel as well as the obtained oil and bioethanol were characterized and it was possible to observe that the contamination of the soils with metals did not affect significantly the quality of the products, namely in concerning metal levels. This study reports thus the successful energetic valorisation of plants grown in degraded soils.info:eu-repo/semantics/publishedVersio

Microbiota-assisted phytoremediation of metal contaminated soils by sunflower

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Biomethane production from phytoremediation derived maize biomass via anaerobic digestion

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Biomethane production from phytoremediation derived maize biomass via anaerobic digestion

info:eu-repo/semantics/publishedVersio

The potential of phytoremediation derived maize biomass for the production of biomethane via anaerobic digestion

Maize is an energetic plant with ability for heavy metals removal from contaminated soil. The growth and ability for heavy metals removal by this energetic culture was tested using an industrialised soil contaminated with zinc (Zn) and cadmium (Cd) vs. an agricultural soil. Plants biomass production and metal accumulation was monitored and resulting biomass (roots, stems and cobs) was used for biogas production in several biomethane assays (BMP) in a factorial design with different inoculum to substrate ratios being tested. The biogas produced during the anaerobic digestion was monitored until stable production and its composition was analysed through gas-chromatography. It was possible to observe that maximum methane production seems to be proportional to the amount of anaerobically degradable substrate and is quickly obtained (ca. 8 days after incubation). It was also noticeable that the metals present in the industrial soil were not damaging to the anaerobic biodegradation of the biomass. The production of biomethane from metal contaminated soils’ phytoremediation derived maize biomass appears thus as a possibility to counterpart biogas production in an increasingly demanding status of renewable energy requirementsinfo:eu-repo/semantics/publishedVersio

Microbiota-assisted phytoremediation of metal contaminated soils by sunflower

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Soil microbiota benefits from phytoremediation coupled to metal-resistant rhizobacteria

Phytoremediation is used for requalifying soils contaminated with heavy metals (HM). Sunflower (Helianthus annuus L.) is one of the most studied species for the remediation of HM-contaminated soils. To increase the bioavailability of nutrients and of metals in soils, metal-resistant plant growth promoting rhizobacteria (PGPR), can be associated to phytoremediation strategies. Soil microbiota can benefit from this association, due to the reduced exposure to HMs toxic effect. In this study, next-generation sequencing (NGS) was applied for investigating shifts in soil microbial community after HMs remediation by sunflowers from a soil amended with Cupriavidus sp. strain 1C2. Sunflower was also grown in a non-contaminated soil (control). Actinobacteria were dominant while Proteobacteria was the second most abundant phylum in both soils. Acidobacteria and Nitrospirae were present in higher relative abundance in the control soil. Results have shown that phytoremediation associated to PGPR induced changes in the contaminated soil microbial community: Acidobacterium (Acidobacteria phylum) and Nitrospira (Nitrospirae phylum) bacterial genera increased their abundance at the end of plant growth. These changes did not occur in the control soil, which presented a more stable bacterial community throughout the experiment. This research increases our knowledge on the relationship between soil microbiota and phytoremediation strategies achievements.info:eu-repo/semantics/publishedVersio

Treatment of wastewaters contaminated with heavy metals using aerobic granules in a sequencing batch reactor

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The potential for energetic valorization of energetic crops derived from phytoremediation

There are presently more than 3 million contaminated sites all over EU, according to the EEA (report 25186 EN). Heavy metal contamination is of particular concern, as metals are not degradable. Soil remediation is becoming a priority and several methods are constantly being tested an implemented. From these, phytoremediation has proven to be an attractive low cost alternative as it acts by establishing a vegetation cover which will stabilize the target sites. However, the fate of harvested biomass is a common obstacle for its implementation. Nonetheless, it can also represent an opportunity for producing added value products. This work presents a novel integrated strategy comprising the utilization of all plant parts for the generation of energy products. Combinations of sunflower and plant growth promoting microbiota were assessed growing in agricultural and metal contaminated soils. Sunflower seeds were then used for oil extraction, with observable extraction efficiencies of up to 20 ml oil/m 2 ; plant stems were used for bioethanol fermentation with yields of up to 280 ml/m 2 ; finally, biodiesel was then produced via transterification of the extracted oil with the produced ethanol, allowing the complete production of a biofuel from this phytoremediation derived biomass. All the products were characterized and it was possible to observe that the presence of metals in the soils did not affect significantly the metal levels on either the oil, the bioethanol or the biodiesel. Additionally, plant roots were used as carbon and energy source for biomethane assays (BMP) for the production of biogas via anaerobic digestion. Overall, it was possible to conclude that soil contaminated with metals was not found to have an important effect on the anaerobic biodegradability of the sunflower roots. This study reports thus the successful energetic valorisation of plants grown in degraded soils as a whole.info:eu-repo/semantics/publishedVersio