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Production of cellobionate from cellulose using an engineered Neurospora crassa strain with laccase and redox mediator addition.

Hildebrand A, Kasuga T, Fan Z - PLoS ONE (2015)

Bottom Line: By adding low concentrations of laccase and a redox mediator to the fermentation, CDH can be efficiently oxidized by the redox mediator, with in-situ re-oxidation of the redox mediator by laccase.The conversion of cellulose to cellobionate was optimized by evaluating pH, buffer, and laccase and redox mediator addition time on the yield of cellobionate.This paper describes a working concept of cellobionate production from cellulose using the CDH-ATBS-laccase system in a fermentation system.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Avenue, Davis, CA, 95616, United States of America.

ABSTRACT
We report a novel production process for cellobionic acid from cellulose using an engineered fungal strain with the exogenous addition of laccase and a redox mediator. A previously engineered strain of Neurospora crassa (F5∆ace-1∆cre-1∆ndvB) was shown to produce cellobionate directly from cellulose without the addition of exogenous cellulases. Specifically, N. crassa produces cellulases, which hydrolyze cellulose to cellobiose, and cellobiose dehydrogenase (CDH), which oxidizes cellobiose to cellobionate. However, the conversion of cellobiose to cellobionate is limited by the slow re-oxidation of CDH by molecular oxygen. By adding low concentrations of laccase and a redox mediator to the fermentation, CDH can be efficiently oxidized by the redox mediator, with in-situ re-oxidation of the redox mediator by laccase. The conversion of cellulose to cellobionate was optimized by evaluating pH, buffer, and laccase and redox mediator addition time on the yield of cellobionate. Mass and material balances were performed, and the use of the native N. crassa laccase in such a conversion system was evaluated against the exogenous Pleurotus ostreatus laccase. This paper describes a working concept of cellobionate production from cellulose using the CDH-ATBS-laccase system in a fermentation system.

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Related in: MedlinePlus

Comparison of the N. crassa laccase to the P. ostreatus laccase in the conversion of cellobiose to CBA using the CDH-ABTS-laccase conversion system.The data shown are the means of biological duplicates with the error bars representing the standard deviations.
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pone.0123006.g006: Comparison of the N. crassa laccase to the P. ostreatus laccase in the conversion of cellobiose to CBA using the CDH-ABTS-laccase conversion system.The data shown are the means of biological duplicates with the error bars representing the standard deviations.

Mentions: The produced laccase was tested against the P. ostreatus laccase in a falcon tube experiment (no cells), where cellobiose, CDH, and ABTS were added and the conversion of cellobiose to CBA monitored as shown in Fig 6. The results indicate that the two laccases have comparable activities, both allowing for efficient conversion of cellobiose to CBA in the CDH-ABTS-laccase conversion system.


Production of cellobionate from cellulose using an engineered Neurospora crassa strain with laccase and redox mediator addition.

Hildebrand A, Kasuga T, Fan Z - PLoS ONE (2015)

Comparison of the N. crassa laccase to the P. ostreatus laccase in the conversion of cellobiose to CBA using the CDH-ABTS-laccase conversion system.The data shown are the means of biological duplicates with the error bars representing the standard deviations.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4388835&req=5

pone.0123006.g006: Comparison of the N. crassa laccase to the P. ostreatus laccase in the conversion of cellobiose to CBA using the CDH-ABTS-laccase conversion system.The data shown are the means of biological duplicates with the error bars representing the standard deviations.
Mentions: The produced laccase was tested against the P. ostreatus laccase in a falcon tube experiment (no cells), where cellobiose, CDH, and ABTS were added and the conversion of cellobiose to CBA monitored as shown in Fig 6. The results indicate that the two laccases have comparable activities, both allowing for efficient conversion of cellobiose to CBA in the CDH-ABTS-laccase conversion system.

Bottom Line: By adding low concentrations of laccase and a redox mediator to the fermentation, CDH can be efficiently oxidized by the redox mediator, with in-situ re-oxidation of the redox mediator by laccase.The conversion of cellulose to cellobionate was optimized by evaluating pH, buffer, and laccase and redox mediator addition time on the yield of cellobionate.This paper describes a working concept of cellobionate production from cellulose using the CDH-ATBS-laccase system in a fermentation system.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Avenue, Davis, CA, 95616, United States of America.

ABSTRACT
We report a novel production process for cellobionic acid from cellulose using an engineered fungal strain with the exogenous addition of laccase and a redox mediator. A previously engineered strain of Neurospora crassa (F5∆ace-1∆cre-1∆ndvB) was shown to produce cellobionate directly from cellulose without the addition of exogenous cellulases. Specifically, N. crassa produces cellulases, which hydrolyze cellulose to cellobiose, and cellobiose dehydrogenase (CDH), which oxidizes cellobiose to cellobionate. However, the conversion of cellobiose to cellobionate is limited by the slow re-oxidation of CDH by molecular oxygen. By adding low concentrations of laccase and a redox mediator to the fermentation, CDH can be efficiently oxidized by the redox mediator, with in-situ re-oxidation of the redox mediator by laccase. The conversion of cellulose to cellobionate was optimized by evaluating pH, buffer, and laccase and redox mediator addition time on the yield of cellobionate. Mass and material balances were performed, and the use of the native N. crassa laccase in such a conversion system was evaluated against the exogenous Pleurotus ostreatus laccase. This paper describes a working concept of cellobionate production from cellulose using the CDH-ATBS-laccase system in a fermentation system.

No MeSH data available.


Related in: MedlinePlus