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Title: Impacts of cellulase deactivation at the moving air–liquid interface on cellulose conversions at low enzyme loadings

Abstract

Background: We recently confirmed that the deactivation of T. reesei cellulases at the air–liquid interface reduces microcrystalline cellulose conversion at low enzyme loadings in shaken flasks. It is one of the main causes for lowering of cellulose conversions at low enzyme loadings. However, supplementing cellulases with small quantities of surface-active additives in shaken flasks can increase cellulose conversions at low enzyme loadings. It was also shown that cellulose conversions at low enzyme loadings can be increased in unshaken flasks if the reactions are carried for a longer time. This study further explores these recent findings to better understand the impact of air–liquid interfacial phenomena on enzymatic hydrolysis of cellulose contained in Avicel, Sigmacell, α-cellulose, cotton linters, and filter paper. The impacts of solids and enzyme loadings, supplementation with nonionic surfactant Tween 20 and xylanases, and application of different types of mixing and reactor designs on cellulose hydrolysis were also evaluated.Results: Avicel cellulose conversions at high solid loading were more than doubled by minimizing loss of cellulases to the air–liquid interface. Maximum cellulose conversions were high for surface-active supplemented shaken flasks or unshaken flasks because of low cellulase deactivation at the air–liquid interface. The nonionic surfactant Tween 20 was unable tomore » completely prevent cellulase deactivation in shaken flasks and only reduced cellulose conversions at unreasonably high concentrations.Conclusions: High dynamic interfacial areas created through baffles in reactor vessels, low volumes in high-capacity vessels, or high shaking speeds severely limited cellulose conversions at low enzyme loadings. Precipitation of cellulases due to aggregation at the air–liquid interface caused their continuous deactivation in shaken flasks and severely limited solubilization of cellulose.« less

Authors:
 [1]; ORCiD logo [2];  [3]
  1. Univ. of California, Riverside, CA (United States). Bourns College of Engineering, Center for Environmental Research and Technology (CE‑CERT) and Center for Environmental Research and Technology (CE‑CERT); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC)
  2. Univ. of California, Riverside, CA (United States). Bourns College of Engineering, Center for Environmental Research and Technology (CE‑CERT) and Center for Environmental Research and Technology (CE‑CERT); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC) and Center for Bioenergy Innovation (CBI)
  3. Univ. of California, Riverside, CA (United States). Bourns College of Engineering, Center for Environmental Research and Technology (CE‑CERT); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). BioEnergy Science Center (BESC) and Center for Bioenergy Innovation (CBI)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1511911
Grant/Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Biotechnology for Biofuels
Additional Journal Information:
Journal Volume: 12; Journal Issue: 1; Journal ID: ISSN 1754-6834
Publisher:
BioMed Central
Country of Publication:
United States
Language:
English
Subject:
Cellulose; Cellulase; Deactivation; Hydrolysis; Air–liquid interface; Gas–liquid interface

Citation Formats

Bhagia, Samarthya, Wyman, Charles E., and Kumar, Rajeev. Impacts of cellulase deactivation at the moving air–liquid interface on cellulose conversions at low enzyme loadings. United States: N. p., 2019. Web. doi:10.1186/s13068-019-1439-2.
Bhagia, Samarthya, Wyman, Charles E., & Kumar, Rajeev. Impacts of cellulase deactivation at the moving air–liquid interface on cellulose conversions at low enzyme loadings. United States. doi:10.1186/s13068-019-1439-2.
Bhagia, Samarthya, Wyman, Charles E., and Kumar, Rajeev. Tue . "Impacts of cellulase deactivation at the moving air–liquid interface on cellulose conversions at low enzyme loadings". United States. doi:10.1186/s13068-019-1439-2. https://www.osti.gov/servlets/purl/1511911.
@article{osti_1511911,
title = {Impacts of cellulase deactivation at the moving air–liquid interface on cellulose conversions at low enzyme loadings},
author = {Bhagia, Samarthya and Wyman, Charles E. and Kumar, Rajeev},
abstractNote = {Background: We recently confirmed that the deactivation of T. reesei cellulases at the air–liquid interface reduces microcrystalline cellulose conversion at low enzyme loadings in shaken flasks. It is one of the main causes for lowering of cellulose conversions at low enzyme loadings. However, supplementing cellulases with small quantities of surface-active additives in shaken flasks can increase cellulose conversions at low enzyme loadings. It was also shown that cellulose conversions at low enzyme loadings can be increased in unshaken flasks if the reactions are carried for a longer time. This study further explores these recent findings to better understand the impact of air–liquid interfacial phenomena on enzymatic hydrolysis of cellulose contained in Avicel, Sigmacell, α-cellulose, cotton linters, and filter paper. The impacts of solids and enzyme loadings, supplementation with nonionic surfactant Tween 20 and xylanases, and application of different types of mixing and reactor designs on cellulose hydrolysis were also evaluated.Results: Avicel cellulose conversions at high solid loading were more than doubled by minimizing loss of cellulases to the air–liquid interface. Maximum cellulose conversions were high for surface-active supplemented shaken flasks or unshaken flasks because of low cellulase deactivation at the air–liquid interface. The nonionic surfactant Tween 20 was unable to completely prevent cellulase deactivation in shaken flasks and only reduced cellulose conversions at unreasonably high concentrations.Conclusions: High dynamic interfacial areas created through baffles in reactor vessels, low volumes in high-capacity vessels, or high shaking speeds severely limited cellulose conversions at low enzyme loadings. Precipitation of cellulases due to aggregation at the air–liquid interface caused their continuous deactivation in shaken flasks and severely limited solubilization of cellulose.},
doi = {10.1186/s13068-019-1439-2},
journal = {Biotechnology for Biofuels},
issn = {1754-6834},
number = 1,
volume = 12,
place = {United States},
year = {2019},
month = {4}
}

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Works referenced in this record:

Supplementation with xylanase and ?-xylosidase to reduce xylo-oligomer and xylan inhibition of enzymatic hydrolysis of cellulose and pretreated corn stover
journal, June 2011

  • Qing, Qing; Wyman, Charles E.
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Techno-economic comparison of process technologies for biochemical ethanol production from corn stover
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