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Effect of Organosolv Lignin and Extractable Lignin on Enzymatic Hydrolysis of Lignocelluloses

Tan, Xin
http://orcid.org/0000-0002-6880-326X
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613752000022518

Abstract Details

2020, PhD, University of Cincinnati, Engineering and Applied Science: Chemical Engineering.
Biofuels, derived from lignocelluloses, is an attractive supplement to fuel produced from non-renewable resources. Various pretreatment methods have been developed to overcome the recalcitrance of lignocelluloses to provide highly digestible substrates for enzymatic hydrolysis. Organosolv pretreatment with ethanol is a promising method for increasing cellulose accessibility, releasing sugars from hemicellulose, and recovering relatively pure lignin as a by-product. The use of other short-chain aliphatic alcohols in the organosolv pretreatment, such as methanol and propanol, was considered to have high-efficiency delignification. The following step of biochemical conversion is enzymatic hydrolysis, by which cellulose and hemicellulose are converted into fermentable sugars. The high cost of enzymes is one of the major bottlenecks in biochemical conversion. In this work, methanol, ethanol, and propanol organosolv lignins from poplar, eucalyptus, aspen, Loblolly pine, and kenaf have been evaluated for their effects on enzymatic hydrolysis of lignocelluloses. Two dimension heteronuclear single quantum coherence spectroscopy (2D-HSQC), heteronuclear single quantum coherence-total correlated spectroscopy (HSQC-TOCSY), and heteronuclear multiple bond correlation spectroscopy (HMBC) have been used to characterize the structure changes of lignins before and after organosolv pretreatment. The spectra of HSQC, HSQC-TOCSY, and HMBC revealed that the alkylation (e.g., methylation, ethylation and propylation) of hydroxyl groups took place not only at Ca, but also at Cß and C?, and potentially also at the phenolic hydroxyl group of lignin. These results showed that propanol organosolv lignins (POLs) from poplar and aspen had higher stimulatory effects than the ethanol and methanol organosolv lignins (EOLs and MOLs) on the enzymatic hydrolysis of Avicel. The alkylation degree will affect the hydrophobicity of resulting organosolv lignins, which in turn will control their positive or negative effect on the enzymatic hydrolysis. Methanol, ethanol and propanol organosolv lignins from poplar and aspen could increase the enzymatic hydrolysis of Avicel by 2-7% while organosolv lignin from eucalyptus and pine decreased the yield of the enzymatic hydrolysis of Avicel by 5-20%. The strong inhibition of eucalyptus and pine lignin on enzymatic hydrolysis might be controlled by their high hydrophobicity.
Maobing Tu, Ph.D. (Committee Chair)
Mingming Lu, Ph.D. (Committee Member)
Yoonjee Park, Ph.D. (Committee Member)
Jingjie Wu, Ph.D. (Committee Member)
Wei Yuan, Ph.D. (Committee Member)
194 p.
Agricultural Engineering
Biomass; Organosolv pretreatment; Enzymatic hydrolysis; Alkylation; Organosolv lignin; Extractable lignin

Recommended Citations

Citations

  • Tan, X. (2020). Effect of Organosolv Lignin and Extractable Lignin on Enzymatic Hydrolysis of Lignocelluloses [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613752000022518

    APA Style (7th edition)

  • Tan, Xin. Effect of Organosolv Lignin and Extractable Lignin on Enzymatic Hydrolysis of Lignocelluloses. 2020. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613752000022518.

    MLA Style (8th edition)

  • Tan, Xin. "Effect of Organosolv Lignin and Extractable Lignin on Enzymatic Hydrolysis of Lignocelluloses." Doctoral dissertation, University of Cincinnati, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613752000022518

    Chicago Manual of Style (17th edition)

ucin1613752000022518
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This open access ETD is published by University of Cincinnati and OhioLINK.