Authors: Wangxia Wang Michael D Mozuch Ronald C Sabo Phil Kersten J Y Zhu Yongcan Jin
Publish Date: 2014/10/12
Volume: 22, Issue: 1, Pages: 351-361
Abstract
A GH5 hyperthermostable endoglucanase from the archaeon Pyrococcus horikoshii PhGH5 and a commercial endoglucanase FR were used to treat bleached eucalyptus pulp BEP fibers to produce cellulose nanofibrils CNFs through subsequent microfluidization Enzymatic treatments facilitated CNF production due to the reduced degree of polymerization DP of the fibers SEM imaging indicated that FR reduced fiber DP drastically and resulted in much shorter fibers than with PhGH5 even at very low dosages 1 mg protein/g fiber of FR treatment compared with a high dosage 10 mg protein/g fiber of PhGH5 The fibers treated with FR were much more uniform in length perhaps due to the presence of exoglucanase and betaglucosidase saccharifying short microfibers into glucose TEM imaging indicated that PhGH5 produced longer and entangled CNFs than FR with the same number of microfluidization passes However the CNF diameters were approximately the same for all CNFs from enzymetreated fibers using both endoglucanases at two dosages 1 or 10 mg protein/g fiber CNFs produced from BEP fibers without enzymatic treatment showed larger diameters than those with enzymatic treatmentWe acknowledge the financial supports by a USDA Agriculture and Food Research Initiative AFRI Competitive Grant No 20116700920056 Chinese Scholarship Council CSC National Natural Science Foundation of China Grant Nos 31070512 and 31370571 The funding from these programs made the visiting appointment of Wang at the USDA Forest Products Laboratory FPL possible We also acknowledge Thomas Kuster of the Analytical Chemistry and Microscopy Lab of FPL for SEM imaging and Debra Sherman of DS imaging LLC West Lafayette IN for TEM imaging
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