Bioethanol production from the green alga ulva rigida and the brown algae macrocystis pyrifera

Ricardo Pezoa Conte, M. Cristina Ravanal, Päivi Mäki-Arvela, Stefan Willför, M. Elena Lienqueo, Jyri Pekka Mikkola

Research output: Chapter in Book/Conference proceedingConference contributionScientificpeer-review

Abstract

Macroalgae are suitable bioresources to be explored as raw material for bioethanol production, as about 40 wt.% of its mass is composed of carbohydrates and they completely lack lignin. In this work the simultaneous saccharification and fermentation (SSF) of the green alga Ulva rigida and the brown alga Macrocystis pyrifera was performed. The algae were initially pretreated in deionized water or diluted sulfuric acid at 125°C in an autoclave for 60 min, respectively. Commercial cellulolytic enzymes and yeast were used for ethanol production. The carbohydrate composition of the fresh alga, pretreated alga and glucose and ethanol concentrations in the SSF processing are given. The water pretreatment solubilized 82 wt.% of the ulvan (rhamno-glucuroxylan) contained in U. rigida and 73 wt.% of the glucan remained in the residue. The diluted acid treatment removed 93 wt.% of the carbohydrates contained in U. rigida. The SSF of U. rigida pretreated with water produced 0.47 g EtOH/g sugar, with a 92 wt.% theoretical yield. In turn, water and diluted acid pretreatment of M. pyrifera increased 8.4 and 14.8 fold the carbohydrate content in the pretreated alga compared to the SSF of the fresh alga. The SSF of M. pyrifera pretreated with dilute sulfuric acid produced 0.15 g EtOH/g sugar, 29 wt.% theoretical yield. The production of ethanol was demonstrated for U. rigida and M. pyrifera with mild pretreatments. Especially in case of U. rigida simple water treatment allows to isolate ulvan for other purposes and efficiently ferment the remaining fibers.

Original languageEnglish
Title of host publicationNWBC 2015 - 6th Nordic Wood Biorefinery Conference
PublisherVTT
Pages319-325
Number of pages7
ISBN (Electronic)9789513883539
Publication statusPublished - 2015
MoE publication typeA4 Article in a conference publication
Event6th Nordic Wood Biorefinery Conference, NWBC 2015 - Helsinki, Finland
Duration: 20 Oct 201522 Oct 2015

Publication series

NameNWBC 2015 - 6th Nordic Wood Biorefinery Conference

Conference

Conference6th Nordic Wood Biorefinery Conference, NWBC 2015
CountryFinland
CityHelsinki
Period20/10/1522/10/15

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