Limits...
Transcriptional analysis of Amorphotheca resinae ZN1 on biological degradation of furfural and 5-hydroxymethylfurfural derived from lignocellulose pretreatment.

Wang X, Gao Q, Bao J - Biotechnol Biofuels (2015)

Bottom Line: During the detoxification process, A. resinae ZN1 firstly reduced furfural or HMF into furfuryl alcohol or HMF alcohol, and then oxidized into furoic acid or HMF acid through furan aldehyde as the intermediate at low concentration level.Two Zn-dependent alcohol dehydrogenase genes and five AKR/ARI genes were found to be responsible for the furfural and HMF conversion to their corresponding alcohols.The genes responsible for the furfural and HMF degradation to the corresponding alcohols and acids in A. resinae ZN1 were identified based on the analysis of the genome annotation, the gene transcription data and the inhibitor conversion results.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China.

ABSTRACT

Background: Furfural and 5-hydroxymethylfurfural (HMF) are the two major inhibitor compounds generated from lignocellulose pretreatment, especially for dilute acid, steam explosion, neutral hot water pretreatment methods. The two inhibitors severely inhibit the cell growth and metabolism of fermenting strains in the consequent bioconversion step. The biodetoxification strain Amorphotheca resinae ZN1 has demonstrated its extraordinary capacity of fast and complete degradation of furfural and HMF into corresponding alcohol and acid forms. The elucidation of degradation metabolism of A. resinae ZN1 at molecular level will facilitate the detoxification of the pretreated lignocellulose biomass and provide the metabolic pathway information for more powerful biodetoxification strain development.

Results: Amorphotheca resinae ZN1 was able to use furfural or HMF as the sole carbon source for cell growth. During the detoxification process, A. resinae ZN1 firstly reduced furfural or HMF into furfuryl alcohol or HMF alcohol, and then oxidized into furoic acid or HMF acid through furan aldehyde as the intermediate at low concentration level. The cell mass measurement suggested that furfural was more toxic to A. resinae ZN1 than HMF. In order to identify the degradation mechanism of A. resinae ZN1, transcription levels of 137 putative genes involved in the degradation of furfural and HMF in A. resinae ZN1 were investigated using the real-time quantitative PCR (qRT-PCR) method under the stress of furfural and HMF, as well as the stress of their secondary metabolites, furfuryl alcohol and HMF alcohol. Two Zn-dependent alcohol dehydrogenase genes and five AKR/ARI genes were found to be responsible for the furfural and HMF conversion to their corresponding alcohols. For the conversion of the two furan alcohols to the corresponding acids, three propanol-preferring alcohol dehydrogenase genes, one NAD(P)(+)-depending aldehyde dehydrogenase gene, or two oxidase genes with free oxygen as the substrate were identified under aerobic condition.

Conclusions: The genes responsible for the furfural and HMF degradation to the corresponding alcohols and acids in A. resinae ZN1 were identified based on the analysis of the genome annotation, the gene transcription data and the inhibitor conversion results. These genetic resources provided the important information for understanding the mechanism of furfural and HMF degradation and modification of high tolerant strains used for biorefinery processing.

No MeSH data available.


Related in: MedlinePlus

Degradation of furfural (a) or HMF (b) without glucose by A. resinae ZN1. Conditions: inoculum 10 % (v/v), 28 °C, natural pH in static state culture. Mean values are presented with error bars representing two standard deviations
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4559888&req=5

Fig2: Degradation of furfural (a) or HMF (b) without glucose by A. resinae ZN1. Conditions: inoculum 10 % (v/v), 28 °C, natural pH in static state culture. Mean values are presented with error bars representing two standard deviations

Mentions: The cell growth and degradation metabolic performance of A. resinae ZN1 were investigated when furfural or HMF was used as the sole carbon source (Fig. 2). Figure 2a shows that furfural was completely utilized within 96 h, and then the cell mass growth started to quickly increase. Furfuryl alcohol and furoic acid increased with the decrease of furfural, then decreased from their maxima and were completely utilized after 144 h. Figure 2b shows that HMF was degraded in a similar way to furfural when HMF was used as the sole carbon source but with a much lower rate. The cell mass quickly increased when only half of the initial HMF was consumed, comparing to the cell mass increasing from almost zero furfural existence. Figure 2 suggests that both furfural and HMF were able to be used as the sole carbon source for the cell growth of A. resinae ZN1, and furfural was more toxic to A. resinae ZN1 than HMF.Fig. 2


Transcriptional analysis of Amorphotheca resinae ZN1 on biological degradation of furfural and 5-hydroxymethylfurfural derived from lignocellulose pretreatment.

Wang X, Gao Q, Bao J - Biotechnol Biofuels (2015)

Degradation of furfural (a) or HMF (b) without glucose by A. resinae ZN1. Conditions: inoculum 10 % (v/v), 28 °C, natural pH in static state culture. Mean values are presented with error bars representing two standard deviations
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4559888&req=5

Fig2: Degradation of furfural (a) or HMF (b) without glucose by A. resinae ZN1. Conditions: inoculum 10 % (v/v), 28 °C, natural pH in static state culture. Mean values are presented with error bars representing two standard deviations
Mentions: The cell growth and degradation metabolic performance of A. resinae ZN1 were investigated when furfural or HMF was used as the sole carbon source (Fig. 2). Figure 2a shows that furfural was completely utilized within 96 h, and then the cell mass growth started to quickly increase. Furfuryl alcohol and furoic acid increased with the decrease of furfural, then decreased from their maxima and were completely utilized after 144 h. Figure 2b shows that HMF was degraded in a similar way to furfural when HMF was used as the sole carbon source but with a much lower rate. The cell mass quickly increased when only half of the initial HMF was consumed, comparing to the cell mass increasing from almost zero furfural existence. Figure 2 suggests that both furfural and HMF were able to be used as the sole carbon source for the cell growth of A. resinae ZN1, and furfural was more toxic to A. resinae ZN1 than HMF.Fig. 2

Bottom Line: During the detoxification process, A. resinae ZN1 firstly reduced furfural or HMF into furfuryl alcohol or HMF alcohol, and then oxidized into furoic acid or HMF acid through furan aldehyde as the intermediate at low concentration level.Two Zn-dependent alcohol dehydrogenase genes and five AKR/ARI genes were found to be responsible for the furfural and HMF conversion to their corresponding alcohols.The genes responsible for the furfural and HMF degradation to the corresponding alcohols and acids in A. resinae ZN1 were identified based on the analysis of the genome annotation, the gene transcription data and the inhibitor conversion results.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237 China.

ABSTRACT

Background: Furfural and 5-hydroxymethylfurfural (HMF) are the two major inhibitor compounds generated from lignocellulose pretreatment, especially for dilute acid, steam explosion, neutral hot water pretreatment methods. The two inhibitors severely inhibit the cell growth and metabolism of fermenting strains in the consequent bioconversion step. The biodetoxification strain Amorphotheca resinae ZN1 has demonstrated its extraordinary capacity of fast and complete degradation of furfural and HMF into corresponding alcohol and acid forms. The elucidation of degradation metabolism of A. resinae ZN1 at molecular level will facilitate the detoxification of the pretreated lignocellulose biomass and provide the metabolic pathway information for more powerful biodetoxification strain development.

Results: Amorphotheca resinae ZN1 was able to use furfural or HMF as the sole carbon source for cell growth. During the detoxification process, A. resinae ZN1 firstly reduced furfural or HMF into furfuryl alcohol or HMF alcohol, and then oxidized into furoic acid or HMF acid through furan aldehyde as the intermediate at low concentration level. The cell mass measurement suggested that furfural was more toxic to A. resinae ZN1 than HMF. In order to identify the degradation mechanism of A. resinae ZN1, transcription levels of 137 putative genes involved in the degradation of furfural and HMF in A. resinae ZN1 were investigated using the real-time quantitative PCR (qRT-PCR) method under the stress of furfural and HMF, as well as the stress of their secondary metabolites, furfuryl alcohol and HMF alcohol. Two Zn-dependent alcohol dehydrogenase genes and five AKR/ARI genes were found to be responsible for the furfural and HMF conversion to their corresponding alcohols. For the conversion of the two furan alcohols to the corresponding acids, three propanol-preferring alcohol dehydrogenase genes, one NAD(P)(+)-depending aldehyde dehydrogenase gene, or two oxidase genes with free oxygen as the substrate were identified under aerobic condition.

Conclusions: The genes responsible for the furfural and HMF degradation to the corresponding alcohols and acids in A. resinae ZN1 were identified based on the analysis of the genome annotation, the gene transcription data and the inhibitor conversion results. These genetic resources provided the important information for understanding the mechanism of furfural and HMF degradation and modification of high tolerant strains used for biorefinery processing.

No MeSH data available.


Related in: MedlinePlus