Changes in brown coal structure caused by coal-solubilizing microorganisms

摘要

The phenomenon of coal solubilization caused by microorganisms has been explained by various mechanisms: extraction of non-covalently bonded polar components of the coal substance by biogenic agents (chelating agents [1], alkaline substances [2] ) and enzyme-catalyzed cleavage of covalent bonds by extracellular enzyme systems [3, 4, 5]. For this it is assumed that bond cleavage occurs on the aliphatic carbon (methylene groups [6], aliphatic bridges [7]) or on ester groups [5]. As the coal has usually been treated with oxidizing agents such as H_2O_2 or HNO_3 before bioconversion, there is a possibility that the result of bioconversion is overlaid with the effect of the chemical treatment. We therefore studied the structural changes in the organic coal substance during pre-oxidation with H_2O_2, treatment with MnP and conversion using the fungal strains of Trichoderma and Fusarium oxysporum.