Mineralization and Kinetics of Reactive Brilliant Red X-3B by a Combined Anaerobic–Aerobic Bioprocess Inoculated with the Coculture of Fungus and Bacterium

Potential use of fungal-bacterial co-cultures for the removal of organic pollutants

Fungi and bacteria coexist in a wide variety of natural and artificial environments which can lead to their association and interaction - ranging from antagonism to cooperation - that can affect the survival, colonization, spatial distribution and stress resistance of the interacting partners. The use of polymicrobial cultivation approaches has facilitated a more thorough understanding of microbial dynamics in mixed microbial communities, such as those composed of fungi and bacteria, and their influence on ecosystem functions. Mixed (multi-domain) microbial communities exhibit unique associations and interactions that could result in more efficient systems for the degradation and removal of organic pollutants. Several previous studies have reported enhanced biodegradation of certain pollutants when using combined fungal-bacterial treatments compared to pure cultures or communities of either fungi or bacteria (single domain systems). This article reviews: (i) the mechanisms of pollutant degradation that can occur in fungal-bacterial systems (e.g.: co-degradation, production of secondary metabolites, enhancement of degradative enzyme production, and transport of bacteria by fungal mycelia); (ii) case studies using fungal-bacterial co-cultures for the removal of various organic pollutants (synthetic dyes, polycyclic aromatic hydrocarbons, pesticides, and other trace or volatile organic compounds) in different environmental matrices (e.g. water, gas/vapors, soil); (iii) the key aspects of engineering artificial fungal-bacterial co-cultures, and (iv) the current challenges and future perspectives of using fungal-bacterial co-cultures for environmental remediation.

Preparation and characterization of a novel Fe3O4-graphene-biochar composite for crystal violet adsorption

A novel Fe₃O₄-graphene-biochar composite (GBC-Fe₃O₄) was prepared to enhance the adsorption capacity and recollection efficiency of graphene-biochar composites (GBCs). The adsorption characteristics were tested to remove crystal violet (CV), which is a refractory compound in industrial wastewater. Structural and morphological analysis exhibited that a larger surface area, greater thermal stability, and more functional groups were present after Fe₃O₄ nanoparticles coated the GBC surface. This improved the CV adsorption versus uncoated GBC. The introduction of G and Fe₃O₄ nanoparticles collectively reduced the zeta potentials of GBC-Fe₃O₄ to -38.1 ± 1.1 mV versus -24.3 ± 2.2 mV for GBC and -20.7 ± 1.2 mV for BC. The maximum Q_max values were obtained 436.68 mg/g at 40 °C. Fourier transform infrared analysis suggested that the interactions of functional groups, such as aromatic C = C and C = O, -OH, C-C, and π-π played an important role in CV adsorption. The thermodynamic analysis of Langmuir and Freundlich isotherms indicated that the adsorption improved as a spontaneous endothermic process. The saturation magnetization of GBC-Fe₃O₄ reached 61.48 emu/g, allowing efficient recollection of the material with a magnet. The CV adsorbability of the re-collected GBC-Fe₃O₄ was 157.31 mg/g, which was slightly lower than freshly prepared GBC-Fe₃O₄ (199 mg/g). These findings demonstrated that GBC-Fe₃O₄ was an efficient and reusable multifunctional biochar.