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Microbial Intervention for Degradation of Agricultural Wastes
Published in Rouf Ahmad Bhat, Moonisa Aslam Dervash, Khalid Rehman Hakeem, Khalid Zaffar Masoodi, Environmental Biotechnology, 2022
Tawseef Ahmad Mir, Muatasim Jan, Mir Sajad Rabani
White rot, biological pretreatment process in wood is generally carried out by a group of different fungi called lignolytic basidiomycetes, generally referred to as white-rot fungi. For the process of degradation of lignin, white-rot fungi are being used over many years (Vicuna, 2000). Species such as Pycnoporus cinnabarinus, Pycnoporus sanguineus, and Phanerochaete chrysosporium have been reported to degrade lignin to a greater extent, similarly Ceriporiopsis subvermispora, phlebia floridensis, p. radiate, and Trichoderma reesei have shown the capability to degrade carbohydrate content with a decrease of 40–60% in lignin content (Lu et al., 2010). When before chemical treatment bio-delignification was used, it showed lignin degradation up to 80% (Yu et al., 2010a, 2010b).
Wood and Wood Modification
Published in Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones, Wood Modification Technologies, 2021
Dick Sandberg, Andreja Kutnar, Olov Karlsson, Dennis Jones
The decomposition of wood by fungi is of two main types, often referred to as brown rot and white rot, together with the less common soft rot (Eriksson et al., 1990; Zabel and Morrell, 1992; Schmidt et al., 1996; Mohebby, 2003; Srivastava et al., 2013). There are also non-destructive fungi that result only in a discolouration of the timber, with no loss of mechanical strength. It has bed been suggested that these staining fungi help to provide channels of attack for wood-destroying fungal. In brown rot, the cellulose and its related pentosans are attacked while the lignin is more or less unchanged. This causes the attacked wood to darken in colour, undergoing shrinkage and cross-cracking into cubical or oblong pieces that can be readily broken and crumbled between the fingers into a brown powder. In white rot, all the components of the wood, including the lignin, may be decomposed and used by the growing fungus. White rot does not produce cross-cracking, but the wood becomes paler in colour, sometimes in pockets or streaks of various sizes and may eventually become a fibrous whitish mass With some white rots, however, the cellulose may remain intact, while the lignin in the secondary wall and middle lamella is almost entirely removed. A graphical view of different rot-type fungi as well as moulds is shown in Figure 1.65 (Teacă et al., 2019).
Soil Remediation
Published in Kathleen Sellers, Fundamentals of Hazardous Waste Site Remediation, 2018
A second enhancement is the addition of white rot fungus to soil. White rot fungi can degrade lignin, a polymeric component of wood which otherwise resists biodegradation. Lignin is structurally similar to certain contaminants. As a result, white rot fungi can degrade organic contaminants such as PAHs, phenolic compounds such as pentachlorophenol, and certain herbicides and pesticides.151,153 By mid-1996, fungal bioremediation had only been applied in the field to wood treating wastes (pentachlorophenol and creosote).154
Production of bioethanol from Saccharum spontaneum by simultaneous saccharification and electro-fermentation using mixed culture of microbes
Published in Biofuels, 2023
Pradip Dhungana, Bikram Prajapati, Puja Bhatt, Dikshya Regmi, Mukesh Yadav, Sujeeta Maharjan, Usha Lamsal, Sanoj Kathariya, Pradip Chaudhary, Jarina Joshi
Certain fungi produce enzymes such as laccases and peroxidases that involved in lignin degradation and other accessory oxidases that generate the hydrogen peroxide required by the peroxidases [23]. Laccase, can detoxify wood hydrolysate, by the removal of monoaromatic phenolic compounds present in the hydrolysate [24], also polymerize phenolic substrates [25]. White rot fungi can break down both cellulose and lignin, the structural components of wood [26].
Endocrine disrupting chemicals (EDCs): chemical fate, distribution, analytical methods and promising remediation strategies – a critical review
Published in Environmental Technology Reviews, 2023
Mridula Chaturvedi, Sam Joy, Rinkoo Devi Gupta, Sangeeta Pandey, Shashi Sharma
White rot fungi are filamentous wood-decay fungi capable of degrading lignin in wood. These belong to basidiomycetes and a few ascomycetes from the order Sphaeriales. The term ‘white-rot’ is derived because of the white appearance of the wood attacked by these fungi. White rot fungi are more commonly found on angiosperm than on gymnosperm wood species in nature [147]. Two decay patterns are produced by white rot fungi (i) Simultaneous decay – in this type of decay, all cell wall components, i.e. cellulose, hemicelluloses and lignin are degraded simultaneously. (ii) Selective decay – in this type of decay pattern, lignin is degraded more or prior to hemicelluloses and cellulose [148]. White rot fungi have high tolerance to an ample range of environmental conditions, involving pH, nutrients and moisture content, and they can use lignocelluloses for growth, making them suitable for inoculation into contaminated soils. In addition, WRF also have advantages over autochthonous micro-organisms for improving the porosity and water-holding capacity of the soil and thus enabling total degradation of recalcitrant compounds. There are several processes involved in bioremediation of EDCs by WRF which are initiated either by ligninolytic enzymes or mycelial-bound redox systems, generating products such as free radicals in terms of proton gradient, which can further undergo enzyme-catalyzed oxidation or non-enzymatic transformations via the process of enzymatic combustion [149]. The ligninolytic enzyme system of white rot fungi is nonspecific with low-molecular-mass mediators that enhance the bioavailability of contaminants to WRF, whereas the intracellular mechanism of bacteria is poorly available to the pollutants, and their uptake may inhibit the bacterial growth [142]. White rot fungi can be grown on inexpensive agro-residues such as wheat straw, corncob, woodchips, sawdust, etc. and the fungus can eliminate EDCs by their adsorption on its biomass itself. There are also other mechanisms that contribute to biotransformation of EDCs, such as Fenton reactions and bio-surfactants produced by fungi. Some relevant species include Pleurotus ostreatus, Phanerochaete chrysosporium, Trametes versicolor, Ganoderma lucidum and Irpex lacteus [150]. The most efficient free and immobilized WRF whole-cell systems are highlighted in Table 4 and Table 5 to indicate their potential in EDCs degradation.