Author(s):
Gomes, Daniel Gonçalves ; Domingues, Lucília ; Gama, F. M.
Date: 2016
Persistent ID: https://hdl.handle.net/1822/42052
Origin: RepositóriUM - Universidade do Minho
Project/scholarship:
info:eu-repo/grantAgreement/FCT/5876/147337/PT;
info:eu-repo/grantAgreement/FCT/5876-PPCDTI/126270/PT
;
info:eu-repo/grantAgreement/FCT/COMPETE/126270/PT;
info:eu-repo/grantAgreement/FCT/5876-PPCDTI/129208/PT
;
info:eu-repo/grantAgreement/FCT/COMPETE/129208/PT;
info:eu-repo/grantAgreement/FCT/SFRH/SFRH%2FBD%2F88623%2F2012/PT;
Subject(s): Recycled paper sludge; Cellulase recycling; Ultrafiltration; Alkaline wash; Cellulosic bioethanol; Science & Technology
Description
The feasibility of cellulase recycling in the scope of bioethanol production from recycled paper sludge (RPS), an inexpensive byproduct with around 39% of carbohydrates, is analyzed. RPS was easily converted and fermented by enzymes and cells, respectively. Final enzyme partition between solid and liquid phases was investigated, the solid-bound enzymes being efficiently recovered by alkaline washing. RPS hydrolysis and fermentation was conducted over four rounds, recycling the cellulases present in both fractions. A great overall enzyme stability was observed: 71, 64 and 100% of the initial Cel7A, Cel7B and -glucosidase activities, respectively, were recovered. Even with only 30% of fresh enzymes added on the subsequent rounds, solid conversions of 92, 83 and 71% were achieved for the round 2, 3 and 4, respectively. This strategy enabled an enzyme saving around 53-60%, while can equally contribute to a 40% reduction in RPS disposal costs.
The authors acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the Project RECI/BBB-EBI/0179/2012 (FCOMP-01-0124-FEDER-027462). The financial support of FCT through GlycoCBMs Project PTDC/AGR-FOR/3090/2012–FCOMP-01-0124-FEDER-027948 and the PhD grant to DG (SFRH/BD/88623/2012) is equally acknowledged. The authors also thank RENOVA (Portugal) for kindly providing the recycled paper sludge.
