白腐真菌东方栓孔菌在两种液体培养基中产漆酶过程的生理学研究

摘要

本研究采用液体培养的方法分析了白腐真菌东方栓孔菌Trametes orientalis在产漆酶过程中生理学指标的变化,即对菌丝体生物量、漆酶活性、还原糖含量、多酚含量、丙二醛(malonaldehyde,MDA)含量、总抗氧化能力(total antioxidant capacity,T-AOC)、超氧化物歧化酶(superoxide dismutase,SOD)活性、过氧化氢酶(catalase,CAT)活性、过氧化氢(hydrogen peroxide,H2O2)水平、抗环血酸(ascorbic Acid,AA)含量、抑制羟自由基能力(restraining ability to hydroxyl free radicals, RAHFR)和1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除能力12项指标进行了测定.结果表明,漆酶能够直接影响白腐真菌对于营养物质的利用情况,其活性大小与菌株的生长状况及次级代谢密切相关;且漆酶活性与多酚含量、MDA含量、CAT活性和AA含量呈正相关,与H2O2水平和RAHFR呈负相关;最终,这些指标可在机体内维持一个稳定的动态、平衡.此外,本文对比了两种培养基Ⅰ和Ⅱ条件下测得的生理学指标,发现在液体培养基Ⅱ中东方栓孔菌具有较高的菌丝体生物量、SOD活性、RAHFR和DPPH自由基清除能力及较低的H2O2水平,说明液体培养基Ⅱ这种缺营养条件可以在一定程度上激发菌株的抗氧化能力以保护机体免受氧化损伤.本研究为进一步加深了解白腐真菌东方栓孔菌的产漆酶特性和大批量液体培养提供了理论指导.%The variations of physiological indexes,viz.mycelial biomass,laccase activity,reducing sugar content,polyphenol content,MDA content,T-AOC,SOD activity,CAT activity,H2O2 level,AA content,RAHFR,and DPPH radicals scavenging ability,of white rot fungus Trametes orientalis were investigated during laccase-producing process under liquid cultivation.The results demonstrated that laccase could directly affect the nutrient utilization of white rot fungus,and its activity was closely related to the fungal growth and secondary metabolism.Laccase activity was positively correlated with polyphenol content,MDA content,CAT activity,and AA content.However,higher RAHFR and H2O2 level had a negative influence on laccase activity.It was concluded that a stable dynamic balance dependent on the above-mentioned indexes was maintained in fungal cells.When compared with the physiological indicators obtained from liquid medium Ⅰ,T.orientalis in liquid medium Ⅱ was shown to exert higher mycelial biomass,SOD activity,RAHFR,and DPPH radicals scavenging activity,as well as lower H2O2 level,suggesting that the liquid medium Ⅱ with absence of nutrition at a certain degree could stimulate the antioxidant activity to protect the fungus from oxidative damage.This study could be used as a theoretical guidance for exploring the laccase-producing characteristics and batch liquid cultivation of white rot fungus T.orientalis.