Experimental Study Of Biodegradation Of Furan Aldehydes And Aromatic Aldehydes Derived From Lignocellulose By Amorphotheca Resinae ZN1

Furan aldehydes and aromatic aldehydes are degradation products of lignocellulose during pretreatment operations. The two aldehydes compounds significantly inhibit the consequent enzymatic hydrolysis and fermentation processes. The biodetoxification fungus Amorphotheca resinae ZN1had demonstrated its excellent capacity on degrading lignocellulose derived inhibitors and helped the fermentation processes to achieve high yield of ethanol and biochemicals. The degradation pathways and performance of furan aldehydes (furfural and5-hydroxymethylfurfural) and aromatic aldehydes (vanillin, coniferyl aldehyde, syringaldehyde and4-hydroxybenzaldehyde) by A. resinae ZNlwere investigated by changing various culture conditions. In this thesis, the phenomenons of furan aldehydes degradation was investigated. The results include:(1) A. resinae ZN1converts furfural/5-HMF into furfuryl/5-HMF alcohols and furoic/5-HMF acids simultaneously at aerobic condition, and only the corresponding furfuryl/5-HMF alcohols are obtained at anaerobic condition;(2) the existence of glucose accelerates the degradation rate of furfural and HMF by A. resinae ZN1and the cell mass growth rate at aerobic culture;(3) glucose is not consumed before furfural or5-HMF is degraded to a low threshold concentration when oxygen exist in tne culture. For degradation of aromatic aldehydes (vanillin, coniferyl aldehyde, syringaldehyde and4-hydroxybenzaldehyde), the reults include:(1) A. resinae ZN1converts aromatic aldehydes into aromatic alcohol and aromatic acid simultaneously at aerobic condition, and aromatic aldehydes was not to be degraded without oxygen;(2) glucose inhibits the degradation of vanillin, coniferyl aldehyde,4-hydroxybenzaldehyde, but improves the degradation rate of syringaldehyde at aerobic condition;(3) the high concentration of vanillin and coniferyl aldehyde inhibit the conversion of glucose, but the high level of4-hydroxybenzaldehyde and syringaldehyde are degraded with glucose at the same time. The pathways of furan aldehydes and aromatic aldehydes were proposed based on the experimental reults. This work provides important information for detoxification enhancement and strain modification.