Research Of Phenol Degradation Perfromance By Phanerochaete Chrysosporium Chlamydospores Packed Bed Reactor And The Transcriptome Sequencing Analusis Of Degradation Mechanism

Phenol is the raw material in industrial production and by-product of many reactions,which has been increased constantly alongside with the development of global industrial development.Because phenol is harmful to environment,plants and animals,the treatment of wastewater containing phenol needs to be solved urgently,therefore,many countries has established the strict standard for the treatment of phenol in wastewater.Phanerochaete chrysosporium is a typical kind of white-rot fungi,which possesses phenol-degrading abilities,and can produce stress-resistant chlamydospores as well as tolerance of high concentration of toxic wastewater,all these characteristics of P.chrysosporium can promise this strain can be used in wastewater treatment frequently.In this research,the degradation conditions of phenol by P.chrysosporium in shake-flask level were optimized firstly,and fitted the degradation kinetic equation.And then,the chlamydospore mycelial pellets of P.chrysosporium are used as the filler of packed bed reactor,and studied the ability of continuous treatment of phenol wastewater as well as the stability and reaction kinetics under different hydraulic retention time.Finally,transcriptome sequencing of P.chrysosporium mycelium and chlamydospore was carried out,and the sequencing data were performed based on bioinformatics analysis.Meanwhile,the composition difference between mycelium and chlamydospore was investigated by infrared spectroscopy.The main research results are as follows:(1)The optimum condition of phenol degradation by P.chrysosporium is initial concentration 701 mg/L,initial pH 6.1,filling mycelial pellets amount 1.98 g,temperature 33?,shaking speed 150 r/min,and the degradation efficiency reach to maximum value at 48 h.(2)The phenol degradation fits First-order Kinetics when the concentration of phenol is lower than 200 mg/L,and the degradation process fits Zero-order Kinetics when the concentration of phenol is 300~1000 mg/L.(3)When the chlamydospore mycelial pellets of P.chrysosporium are chosed as the filler of packed bed reactor,the optimum condition is filling mycelial pellets amount 40 g,retention time 2h,influent concentration is lower than 1000 mg/L.(4)Under the optimal conditions,the degradation rate of the reactor was stable at about 60% for 10 days and dropped significantly during two weeks.(5)Under the optimal conditions,the degradation of this reactor fits First-order Kinetics when the retention time is 1h,2h or 3h and influent concentration is 1000 mg/L.(6)Ten samples acquired from different periods of mycelium and chlamydospore were carried out by transcriptome sequenced using Illumina Hiseq platform.A total of 40 G sequencing data were obtained,while each simple obtained around 30000000 raw reads and clear reads.(7)The number of differential expression genes between mycelium and chlamydospore were less than the number of differential gene during the growth and in the process of metabolism between mycelium and chlamydospore.And 50 specific differential expression genes between mycelium and chlamydospore was the key gene to its biological functions and properties.(8)Based on the comparison of KEGG pathway,biosynthesis of secondary metabolism,tyrosine metabolism,RNA transport,Ribosome,Histidine metabolism and MAPK signaling pathway are significant difference between mycelium and chlamydospore,which could directly or indirectly affect the degradation ability of phenol through influenced the chlamydospores and hyphal cell structure.(9)The component analysis of chlamydospore and mycelium were determined with using infrared spectroscopy,the chlamydospore contained more protein and lipoid,while mycelium contained more saccharide.