| Literature DB >> 24275024 |
James F Humpula1, Nirmal Uppugundla1, Ramin Vismeh2, Leonardo Sousa1, Shishir P S Chundawat3, A Daniel Jones2, Venkatesh Balan1, Bruce E Dale1, Albert M Cheh4.
Abstract
Sequential fractionation of AFEX-pretreated corn stover extracts was carried out using ultra-centrifugation, ultra-filtration, and solid phase extraction to isolate various classes of pretreatment products to evaluate their inhibitory effect on cellulases. Ultra-centrifugation removed dark brown precipitates that caused no appreciable enzyme inhibition. Ultra-filtration of ultra-centrifuged AFEX-pretreated corn stover extractives using a 10 kDa molecular weight cutoff (MWCO) membrane removed additional high molecular weight components that accounted for 24-28% of the total observed enzyme inhibition while a 3 kDa MWCO membrane removed 60-65%, suggesting significant inhibition is caused by oligomeric materials. Solid phase extraction (SPE) of AFEX-pretreated corn stover extractives after ultra-centrifugation removed 34-43% of the inhibition; ultra-filtration with a 5 kDa membrane removed 44-56% of the inhibition and when this ultra-filtrate was subjected to SPE a total of 69-70% of the inhibition were removed. Mass spectrometry found several phenolic compounds among the hydrophobic inhibition removed by SPE adsorption.Entities:
Keywords: AFEX; AFEX-CS; AFEX-CS-E; AFEX-treated corn stover; Cellulase; Fractionation; Inhibition; MP; MX; Multifect Pectinase; Multifect Xylanase; SPE; UC; UC-AFEX-CS-E; UF; UF-UC-AFEX-CS-E; Ultra-filtration; aqueous extract of AFEX-treated corn stover; solid phase extraction; ultra-centrifugation; ultra-centrifuged and ultra-filtered aqueous extract of AFEX-treated corn stover; ultra-centrifuged extract of AFEX treated corn stover; ultra-filtration
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Year: 2013 PMID： 24275024 DOI： 10.1016/j.biortech.2013.10.082
Source DB: PubMed Journal: Bioresour Technol ISSN： 0960-8524 Impact factor: 9.642