Recombinant alginate lyases and mannitol dehydrogenase enhance hydrolysis of macroalgal carbohydrates

IF 3.4 3区生物学 Q2 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Enzyme and Microbial Technology Pub Date : 2025-02-26 DOI:10.1016/j.enzmictec.2025.110618

Dominique F. Rocher, Marthinus W. Myburgh, Marinda Viljoen-Bloom, Rosemary A. Cripwell

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引用次数: 0

Abstract

Brown macroalgae are a promising source for bioethanol production, primarily due to their high carbohydrate, low lignin and high moisture content. Bioconversion of macroalgae to ethanol requires a yeast, such as Saccharomyces cerevisiae, that can hydrolyse the macroalgal carbohydrates, namely laminarin, mannitol and alginate. In this study, the mannitol dehydrogenase (MDH) genes from Aspergillus fumigatus (AfMDH) and Talaromyces islandicus (TiMDH), and the alginate lyase (AL) genes from Sphingomonas sp. (SpxAL and SpeAL) and Talaromyces emersonii (TeeAL) were expressed in the laboratory strain, S. cerevisiae Y294. Co-cultures of a laminarinase-producing yeast, Y294[Relam1/Tvlam1] and yeasts expressing mannitol dehydrogenases and alginate lyases were evaluated for the consolidated bioprocessing of the major carbohydrates in brown macroalgae. Laminarin and mannitol were targeted for ethanol production, while alginate was depolymerised to expose mannitol. A co-culture of S. cerevisiae Y294[Relam1/Tvlam1], [AfMDH] and [TeeAL/SpxAL] strains produced 10.30 g/L ethanol from Ecklonia maxima, representing a 98 % carbon conversion (based on the laminarin and mannitol content). A strain expressing both endo- and exo-alginate lyase improved the ethanol yield by 42.28 % compared to strains expressing only laminarinase- and mannitol dehydrogenase. Scanning electron microscopy further revealed that co-cultures containing laminarinase, MDH, and AL enzymes promoted significant physical degradation and increased porosity in macroalgal substrates, suggesting enhanced alginate hydrolysis and improved enzyme accessibility. This is the first report on the simultaneous hydrolysis of mannitol, alginate and laminarin with recombinant enzymes during macroalgal fermentation. The results demonstrate significant progress towards exploiting brown macroalgae for bioconversion to ethanol and high-value products.

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来源期刊

Enzyme and Microbial Technology 生物-生物工程与应用微生物

CiteScore

7.60

自引率

5.90%

发文量

142

审稿时长

38 days

期刊介绍： Enzyme and Microbial Technology is an international, peer-reviewed journal publishing original research and reviews, of biotechnological significance and novelty, on basic and applied aspects of the science and technology of processes involving the use of enzymes, micro-organisms, animal cells and plant cells. We especially encourage submissions on: Biocatalysis and the use of Directed Evolution in Synthetic Biology and Biotechnology Biotechnological Production of New Bioactive Molecules, Biomaterials, Biopharmaceuticals, and Biofuels New Imaging Techniques and Biosensors, especially as applicable to Healthcare and Systems Biology New Biotechnological Approaches in Genomics, Proteomics and Metabolomics Metabolic Engineering, Biomolecular Engineering and Nanobiotechnology Manuscripts which report isolation, purification, immobilization or utilization of organisms or enzymes which are already well-described in the literature are not suitable for publication in EMT, unless their primary purpose is to report significant new findings or approaches which are of broad biotechnological importance. Similarly, manuscripts which report optimization studies on well-established processes are inappropriate. EMT does not accept papers dealing with mathematical modeling unless they report significant, new experimental data.