Oxygen radical based on non-thermal atmospheric pressure plasma alleviates lignin-derived phenolic toxicity in yeast
Oxygen radical based on non-thermal atmospheric pressure plasma alleviates lignin-derived phenolic toxicity in yeast
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DOI：
10.1186/s13068-020-1655-9
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发表时间：
2020-01-28
影响因子：
6.3
通讯作者：
Shimizu, Motoyuki
中科院分区：
文献类型：
--
作者：
Ito, Shou;Sakai, Kiyota;Shimizu, Motoyuki
研究背景香草醛是木质纤维素生物质经碱处理后生产发酵糖的主要副产物，是酵母发酵产乙醇的有效抑制剂。在从木质纤维素生物质工业生产生物乙醇的过程中，酵母细胞通常暴露于香草醛。因此，香草醛毒性是降低生物乙醇生产成本的主要障碍。结果分析了氧自由基处理对香草醛分子的影响。我们的研究结果表明，香草醛转化为香草酸，原儿茶醛，原儿茶酸，甲氧基对苯二酚，3，4-二羟基-5-甲氧基苯甲醛，三羟基-5-甲氧基苯，以及它们各自的开环产物，其显示相对于香草醛的毒性降低，并导致降低香草醛对酵母的毒性。此外，经过16小时的孵育，乙醇浓度在氧自由基处理的香草醛溶液是7.0倍大于从未处理的解决方案，观察到类似的结果，使用碱预处理的稻草浆与氧自由基处理。结论氧自由基处理对碱预处理稻草浆中香草醛分子的影响，可使香草醛转化为衍生物，从而降低乙醇发酵过程中香草醛对酵母的毒性。这些研究结果表明，化学和氧自由基处理的组合提高了使用酵母细胞的乙醇生产，并且植物生物质的氧自由基处理为进一步改进生物乙醇生产过程提供了很大的希望。
Background Vanillin is the main byproduct of alkaline-pretreated lignocellulosic biomass during the process of fermentable-sugar production and a potent inhibitor of ethanol production by yeast. Yeast cells are usually exposed to vanillin during the industrial production of bioethanol from lignocellulosic biomass. Therefore, vanillin toxicity represents a major barrier to reducing the cost of bioethanol production. Results In this study, we analysed the effects of oxygen-radical treatment on vanillin molecules. Our results showed that vanillin was converted to vanillic acid, protocatechuic aldehyde, protocatechuic acid, methoxyhydroquinone, 3,4-dihydroxy-5-methoxybenzaldehyde, trihydroxy-5-methoxybenzene, and their respective ring-cleaved products, which displayed decreased toxicity relative to vanillin and resulted in reduced vanillin-specific toxicity to yeast during ethanol fermentation. Additionally, after a 16-h incubation, the ethanol concentration in oxygen-radical-treated vanillin solution was 7.0-fold greater than that from non-treated solution, with similar results observed using alkaline-pretreated rice straw slurry with oxygen-radical treatment. Conclusions This study analysed the effects of oxygen-radical treatment on vanillin molecules in the alkaline-pretreated rice straw slurry, thereby finding that this treatment converted vanillin to its derivatives, resulting in reduced vanillin toxicity to yeast during ethanol fermentation. These findings suggest that a combination of chemical and oxygen-radical treatment improved ethanol production using yeast cells, and that oxygen-radical treatment of plant biomass offers great promise for further improvements in bioethanol-production processes.