Nano zero-valent iron (nZVI) has been shown to facilitate biofuel production, notably in hydrogen generation. However, its effect on bioethanol production is rarely studied, and even less so on its impact on hydrogen and ethanol co-production. This study therefore conducted ethanol-type hydrogen-producing fermentation with brown algae to explore the effect of nZVI. With the supplementation of nZVI, fermentation was accelerated and the production of hydrogen and ethanol were both significantly enhanced. At the optimal nZVI concentration of 100 mg/L, the production of hydrogen and ethanol increased by 71.44% and 65.11%, respectively. A high hydrogen yield of 2.32 mol/mol-mannitol was achieved. The ethanol yield (1.86 mol/mol-mannitol) reached 93% of the theoretical maximal yield with a high selectivity of 91.09%. Electron distribution analysis showed that nZVI increased the total electron amounts of fermentation, and directed more electrons to ethanol than hydrogen. The reduced redox potential (ORP) and increased NADH level further confirmed the role of nZVI. Moreover, nZVI fostered Fe2+ availability to hydrogen-producing bacteria, enhancing the enzymes hydrogenase and alcohol dehydrogenase, as well as cell biomass. The bioenergy conversion efficiency (BioECE) improved from 19.08% to 31.74% with 100 mg/L nZVI treatment. This study provided a first demonstration regarding the role of nZVI in hydrogen and ethanol co-production, highlighting the great potential of multiple bioenergy recovery from marine biomass.

中文翻译：

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通过补充纳米零价铁 （nZVI） 增强褐藻发酵中氢气和乙醇的共产


纳米零价铁 （nZVI） 已被证明可以促进生物燃料的生产，尤其是在制氢方面。然而，它对生物乙醇生产的影响很少被研究，对氢气和乙醇联合生产的影响更是如此。因此，本研究用褐藻进行了乙醇型产氢发酵，以探讨 nZVI 的效果。随着 nZVI 的添加，发酵加速，氢气和乙醇的产生都显着增强。在 100 mg/L 的 nZVI 最佳浓度下，氢气和乙醇的产量分别提高了 71.44% 和 65.11%。实现了 2.32 mol/mol-甘露醇的高氢气产率。乙醇产率 （1.86 mol/mol-甘露醇） 达到理论最大产率的 93%，选择性高达 91.09%。电子分布分析表明，nZVI 增加了发酵的总电子量，并且比氢更多地将电子引导到乙醇。氧化还原电位 （ORP） 降低和 NADH 水平升高进一步证实了 nZVI 的作用。此外，nZVI 促进了 Fe2+ 对产氢细菌的可用性，增强了氢化酶和醇脱氢酶以及细胞生物量。100 mg/L nZVI 处理后，生物能源转换效率 （BioECE） 从 19.08% 提高到 31.74%。这项研究首次证明了 nZVI 在氢和乙醇联合生产中的作用，突出了从海洋生物质中回收多种生物能的巨大潜力。