Approach to a High-Level Production of the Basidiomycetous Ligninolytic Enzymes in Secretory Expression Systems of Genetically Modified Yeast

点击翻译按钮获取中文摘要

White-rot basidiomycetous fungi degrade xenobiotic lignin that is the most complex polymer among naturally occurring high-molecular weight materials. Lignin contains large quantities of potentially useful raw materials, and hence the work on the basidiomycetous ligninolytic enzymes is encouraged. Recent studies have shown that fungi also effectively degrade artificial xenobiotics, such as 2,4,6-trichlorophenol, polychlorinated biphenyls (PCBs), and chlorinated dibenzo-p-dioxin, Degradation of these xenobiotics by white-rot fungi is largely dependant on the reaction of secreted enzymes, major of which are ligin peroxidase (LiP), manganese peroxidase(MnP) and laccase.High production of ligninolytic enzymes in fungi is difficult because of their low growth activity. Recent studies prefer to overcome the limitation with the use of yeast Pichia pastor is that is one of the best characterized eukaryotic expression systems. Thus the present study was undertaken to presernt data for a formulation of a high-level production of the basidiomycetous ligninolytic enzymes in secretory expression systems of genetically modified P.pastoris.Large amount of EcoRI was obtained from the supernatant of the culture of P.pastoris GS115 that was transformed with the the EcoRIr^+ gene. This experiment corroborates the usefulness of P.pastoris for foreign protein productions.Lignin and bisphenol A, which is used as an artificial xenobiotics, were then treated by white-rot basidiomycetousfungi, Coriolus hirstus IFO4917 and Elfvingia applanata SMC700. Both were effectively degraded. Degradation of lignin was almost concurrent with MnP activity. Thus a gene encoding a MnP was cloned from E.applanata. TheMnP gene was consisted of 1,095 bp ORF coding for 364 amino acid residues.