Dissolution Of Antibiotics Mycelium In Ionic Liquids And Its Utilization

The vast majority of antibiotics was produced in China.While,about 2 million tons of antibiotics mycelium residue generated and urgently need to disposal every year in domestic.The mycelium are rich in proteins,chitin and glucan,it can be as a kind of useful and renewable raw material of biopolymers.But,it is hard for mycelium dissolving in conventional solvents,such as water,dilute acids,dilute alkalis,and traditional organic solvents,limits the extraction and utilization of these biopolymers.In this work,a novel dissolution of penicillin G fermentation mycelium using ionic liquids(ILs)as solvent was proposed and investigated.The key influences of ILs' structures on mycelium dissolution performance were determined.The dissolution and regeneration mechanism were also explored.The recovery process of biopolymer was accomplished.This work provides a novel method for utilization of antibiotics mycelium.The main innovative work and results are as follows:(1)The dissolution of mycelium in different ILs and oganic solvent-IL complex solvent were investigated.The effects of key factors on dissolution capacity were investigated,and the optimal solvent and conditions were obtained.The results showed that mycelium could be dissolved in some hydrophilic ILs at room temperature,and the solubility of mycelium increased with increasing temperature.[Bmim]Ac was the most effective IL and the optimal temperature,mass ratio of mycelium to[Bmim]Ac and dissolution time were 90?,3.90:1 and 60min,respectively.At the optimal conditions,the dissolution percentage and solubility were 84.70%(wt)and 43.08 g·mol-1.Synergistic effect of[Bmim]Ac and co-solvent DMSO was confirmed and the dissolution of penicillin mycelium increased by 35.50%.(2)The quantitative correlation of solubility and structures of ILs was studied using solvatochromic probes.The mycelium dissolution mechanism and active sites of IL were studied using NMR and FT-IR spectroscopy.The results showed that both the anion and cation of ILs are crucial for the dissolution performance of mycelium.There was a linearly positive correlation between Kamlet-Taft parameters ? and ? of the ILs and mycelium solubility.NMR and FT-IR spectra showed that hydrogen bond was the driving force of dissolution.Oxygen atoms of both C=O and C-O in Ac and aromatic protons H2,H4 and H5 of cation were the active sites of[Bmim]Ac.(3)Based on the efficient dissolution of mycelium,the recovery process of biopolymer was investigated.The effect of precipitant on recovery rate was studied and biopolymer film was prepared.The component of recovered biopolymer were characterized and the regeneration mechanism was studied by FT-IR spectra.The results showed that hydrogen bond donating ability of precipitant was crucial for recovery.By the two step of precipitation and evaporation,the total recovery rate of biopolymer reached 73.93%.The biopolymer prepared by precipitation contained protein and sugar,the contents of them were 44.59%and 48.47%.After extraction of ILs by acetone,the biopolymer was prepared by evaporation,the main component was water-soluble sugar.The regeneration of biopolymer was attributed to the rebuilt of hydrogen bond of biopolymer in mycelium.