Bioaccumulation of toxic metals by fungi of the genus Aspergillus isolated from the contaminated area of Ostramo Lagoons

The study compares the ability to bioaccumulate toxic metal ions using microscopic filamentous fungi of the genus Aspergillus isolated from the anthropogenically contaminated site of the Ostramo Lagoons (Ostrava, Czech Republic). The experiment comprised six species of indigenous fungal isolates: A. niger, A. candidus, A. iizukae, A. westerdijkiae, A. ochraceus and A. clavatus. Nutrient liquid media enriched with Cu(II), Zn(II), Ni(II) and Cr(III) were individually inoculated with spores of these fungi. After thirty days of incubation, the content of metal ions in the dried fungal biomass and medium was measured by the AAS. It was found that the average bioaccumulation capacity of selected toxic metal within the tested strains decreases in the following order: A. ochraceus > A. candidus > A. clavatus > A. westerdijkiae > A. iizukae > A. niger. The highest bioaccumulation efficiency was achieved by the A. ochraceus strain which accumulated Cu(II) with an efficiency of 57.42 %, Zn(II) with 56.88 %, Cr(III) with 37.73 %. When comparing the ability of bioaccumulation of the toxic metals, the following was found: Zn(II) > Cu(II) > Cr(III) > Ni(II). Understanding of bioaccumulation processes that take place in fungal cells at the molecular level may lead to better strategies for the application of these interesting microorganisms in bioremediation processes.

Cascading Recycling of Wood Waste: A Review

Wood is an increasingly demanded renewable resource and an important raw material for construction and materials. In addition, new consumption habits are leading to the production of ever greater volumes of waste wood, which constitutes a feedstock that can be mobilized for the cascade production of new materials such as particleboard. However, current legislation and wood waste recycling processes need to be improved in order to maximize the volumes that can be reused and to upgrade the properties of the recycled wood. This review describes wood waste flows and volumes available in Europe, the current French and European legislation, and the innovations under development in this field: innovative automated sorting techniques, physical-chemical processes for cleaning residual glue from the surface of wood particles, cleaning of MDF, and bioremediation processes for cleaning hazardous wood contaminated by heavy metals or creosote.

Tolerance of Microorganisms to Heavy Metals

Heavy metal pollution is a growing environmental concern due to the increase in anthropogenic-based sources. Microorganisms have high adsorptive capacities and surface-area-to-volume ratio that enable the uptake of these contaminants and their conversion to innocuous complexes in the process of bioremediation. This chapter explores the mechanisms and specific microorganisms that are resistant to metal toxicity. A wide range of bacterial, algae, and fungal species used as biosorbents are highlighted. Mechanisms such as reduction of metal cations, their sequestration, and binding on cell barriers are discussed. To optimise the efficacy of microorganisms in bioremediation processes, adoption of genetic and nano-technologies is recommended.

Safe Use of Wastewater in Agriculture Through Bioremediation Processes

Population growth, industrialisation, urbanisation, and climate change have created huge pressure on freshwater resources to fulfil the demand. Approx. 70-80% of the freshwater supply returns as wastewater, which is difficult to tackle and manage. We need to tackle the freshwater demand from different sectors like domestic, industrial, and agriculture. Most important is how to use the wastewater safely in agriculture. Therefore, it is an apt time to refocus on ways to recycle water especially in sectors like agriculture and for ecosystem services. The major concern in using wastewater in agriculture is its quality as the wastewater may carry pathogens, heavy metals, and many other pollutants, which might reach to human beings and animals via food chain. A solution to wastewater reuse is through bioremediation techniques. Bioremediation should be considered as a feasible and futuristic technology for safe use of wastewater in agriculture as it will reduce the burden on centralised water treatment system as well as it being economic and eco-friendly.

Biodegradation of the Polycyclic Aromatic Hydrocarbon Fluoranthene by Fungi Strains from a Brazilian Tropical Peat

Polycyclic aromatic hydrocarbons (PAHs) are an important environmental issue and the identification of new biocatalysts for an efficient biodegradation of these compounds is essential for bioremediation. Therefore, fungi strains isolated for the first time from a tropical peat at Santo Amaro das Brotas (Brazil) were studied for fluoranthene biodegradation. Fusarium sp. AC-7, Penicillium sp. AC-1 and Penicillium sp. AC-6 were isolated using fluoranthene as sole carbon source. All strains were tested for biodegradation of 100 mg L-1 fluoranthene during 14 and 28 days. After 28 days of biodegradation, 64 ± 3, 60 ± 4 and 51 ± 2% biodegradation was observed for Penicillium sp. AC-1, Penicillium sp. AC-6 and Fusarium sp. AC-7, respectively. Analysis of the obtained compounds enabled the identification of four metabolites, which were common to the three employed strains: anthrone, anthraquinone, 9-methoxyanthracene and cyclopropa[1]phenanthrene. It is important to note that control experiments were performed. The obtained results clearly demonstrated the efficiency of tropical peat fungi in the transformation of fluoranthene. These findings showed the potential of tropical peats for isolation of fungi and indicated that these strains can be applied for bioremediation processes of areas contaminated with fluoranthene and other PAHs.