Sorption Change in Electric Resistance of a Varnished Cambric Insulation by Exposure to the Microscopic Fungus Aspergillus niger

Abstract The paper presents an inhibition effect of clay mineral – montmorillonite – on the growth of microscopic filamentous fungus Aspergillus niger in the aqueous solution. The significant reduction in growth of the final size of spherical fungal pellets as well as total amount of produced microbial biomass was found out. Within the observed range of additions of clay mineral of 1, 5, 10, 15 and 20 g in the total volume of the 80 ml suspension, this size was in indirect relation to the weight of montmorillonite. However, the most significant inhibition effect was observed at the lowest concentration of the sorbent (1 g). Microscopic analysis of pellets referred to the presence of mineral particles in their pore structure and the distribution of particles in the spatial structure of fungal hyphae was variable. The experiment clearly demonstrated an inhibition effect of montmorillonite. This inhibition could be answered by the experiments focused on the detection of the influence of size and shape of inorganic sorption particles together with the influence of the physicochemical properties of its surface. It could be stated that the simultaneous application of the microscopic fungus Aspergillus niger and the clay mineral montmorillonite for decontamination of waste waters should be disadvantage due to their interaction if compared with the decontamination based on bioaccumulation and sorption separately.

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Simultaneous lithium bioleaching and bioaccumulation from lepidolite using microscopic fungus Aspergillus niger

Nova Biotechnologica et Chimica ◽

10.36547/nbc.v19i2.771 ◽

2020 ◽

Vol 19 (2) ◽

pp. 175-182

Author(s):

Renáta Marcinčáková ◽

Alena Luptáková ◽

Marek Vojtko ◽

Martin Fujda ◽

Jana Sedláková-Kaduková

Keyword(s):

Citric Acid ◽

Aspergillus Niger ◽

Filamentous Fungus ◽

Glucose Concentration ◽

Fungal Biomass ◽

Hard Rock ◽

Silicate Phase ◽

Microscopic Fungus ◽

Sem Analyses

The leaching of lithium from lepidolite using the filamentous fungus Aspergilluss niger was examined. Two mechanisms were suggested – biochemical using citric acid as the main bioleaching agent and biomechanical through hyphae penetration confirmed by XRD and SEM analyses. The bioleaching processes were conducted at various glucose concentrations (5 – 20 g.L-1). The higher glucose concentration was, the higher Li bioleaching was observed. Li accumulation by fungal biomass played an important role in Li solubilisation from lepidolite. Totally, 11.5 mg of lithium were recovered from 1 kg of lepidolite by combination of bioleaching and bioaccumulation processes. As a result of bioleaching, the formation of new silicate phase of SiO2 was detected. According to the results, fungal bioleaching of Li from lepidolite can be a perspective way of Li recovery from hard-rock ores.

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Iron Oxalate Humboldtine Crystallization by Fungus Aspergillus niger

Crystals ◽

10.3390/cryst11121591 ◽

2021 ◽

Vol 11 (12) ◽

pp. 1591

Author(s):

Marina S. Zelenskaya ◽

Alina R. Izatulina ◽

Olga V. Frank-Kamenetskaya ◽

Dmitry Y. Vlasov

Keyword(s):

Aspergillus Niger ◽

Solid Substrate ◽

Oxidation States ◽

Calcium Oxalate Crystals ◽

X Ray Diffraction ◽

Microscopic Fungus ◽

X Ray ◽

Iron Oxalate ◽

Iron Bearing

Microfungi were able to alternate solid substrate in various environments and play a noticeable role in the formation of insoluble calcium oxalate crystals in subaerial biofilms on rock surfaces. The present work describes how iron oxalate dihydrate humboldtine is acquired under the influence of the acid-producing microscopic fungus Aspergillus niger on the surface of two iron- bearing mineral substrates in vitro. Pyrrhotite and siderite rocks, as well as the products of their alteration, were investigated using a complex of analytical methods, including powder X-ray diffraction, optical microscopy, scanning electron microscopy and EDX spectroscopy. The effect of the underlying rocks with different composition and solubility and different oxidation states of iron on Fe-oxalate crystallization and on the morphology of humboldtine crystals was shown. The mechanisms of humboldtine formation were discussed. The results obtained in vitro seem promising for using fungi in bioleaching iron and other metals from processed ores and for the development of environmentally friendly biotechnologies.

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